^^11^^^^ United States Department of Commerce

i I^^S I National Institute of Standards and Technology

NIST

PUBLICATIONS

NIST Special Publication 807

U.S. Assessment of the New

Diamond Technology in Japan

Albert Feldman and Lyle H. Schwartz, Editors

NAT L INST. OF STAND & TECH fl.I.C.

QC -

100

.U57

#807

1991

NIST Special Publication 807

U.S. Assessment of the New

Diamond Technology in Japan

Edited by

Albert Feldman

Lyle H. Schwartz

Materials Science and Engineering Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899

U.S. Department of Commerce

Robert A. Mosbacher, Secretary

National Institute of Standards and Technology

John W. Lyons, Director

January 1991
National Institute of Standards U.S. Government Printing Office

and Technology Washington: 1991

Special Publication 807

Natl. Inst. Stand. Technol.

Spec. Publ. 807

96 pages (Jan. 1991)

CODEN: NSPUE2

For sale by the Superintendent

of Documents

U.S. Government Printing Office

Washington, DC 20402
CONTENTS

CONCLUSIONS 4

RECOMMENDATIONS 5

INTRODUCTION 7

GENERIC RESEARCH 11

DEPOSITION TECHNOLOGIES 11

NUCLEATION 16

CHEMICAL AND PHYSICAL PROPERTIES 17

ADHESION, BONDING AND HARDNESS 20

DOPING OF DIAMOND FILMS 21

DIAMOND EPITAXIAL GROWTH 22

POST DEPOSITION PROCESSING 23

APPLICATIONS 27

INTRODUCTION 27

MACHINE TOOLS AND ABRASIVES 27

THERMAL MANAGEMENT 30

ELECTRONIC AND OPTOELECTRONIC DEVICES 31

OPTICAL APPLICATIONS: COATINGS, LENSES, WINDOWS AND

X-RAY WINDOWS 32

MANUFACTURING TECHNOLOGY 36

COMMERCIALIZATION 38

THE GOVERNMENT ROLE 40

APPENDIX A - Planning and Implementation of the Assessment 43

APPENDIX B - Brief Assessment of the New Diamond Technology in

Europe and in Other Countries 45

APPENDIX C - Site Visit Reports 48

APPENDIX D - Admins tration of Science and Technology in Japan 75

APPENDIX E - Delegation Members 80

APPENDIX F - Biographies of Delegation Members 82

APPENDIX G - Itinerary 87

APPENDIX H - List of Companies, Universities, and

Government Agencies Visited 89

APPENDIX I - Alphabetical Listing of Abbreviations 92

iii
U.S. ASSESSMENT OF THE NEW DIAMOND TECHNOLOGY IN JAPAN

Contributing Authors

Lyle H. Schwartz, Chairman

National Institute of -Standards and Technology

John C. Angus

Case Western Reserve University

Jerome J . Cuomo

IBM Research Laboratory

Albert Feldman

National Institute of Standards and Technology

Jeffrey T. Glass

North Carolina State University

Sandor Holly

Rockwell International

James W. Mitchell

AT&T Bell Laboratories

Ronald A. Rudder

Research Triangle Institute

Keith A. Snail

Naval Research Laboratory

C. Martin Stickley

BDM International, Inc.

(Currently University of Central Florida)

Michael A. Tamor

Ford Motor Company

Walter A. Yarbrough

Pennsylvania State University

iv
U.S. ASSESSMENT OF THE NEW DIAMOND TECHNOLOGY IN JAPAN

ABSTRACT

This assessment of Japanese diamond technology was undertaken at the request

of the joint committees for implementation of the 1988 United States- Japan

Agreement on Cooperation in Research and Development in Science and Technology

under the auspices of the Committee on Materials, Office of Science and

Technology Policy. The purposes of the study were to assess the level of

scientific activity, areas of intended commercialization, progress in

commercialization, the role of the Japanese government in assisting industry

to exploit the new diamond technology, and the relative positions of Japan and

the U.S. in all aspects of synthesized diamond technology. Japanese efforts

were chosen for assessment because Japan is the apparent world leader in the

drive for commercialization of this technology. The principal focus of the

study was diamond produced by chemical vapor deposition, with a peripheral

investigation of cubic boron nitride and diamond- like carbon. Based on this

assessment, a set of Conclusions and Recommendations is presented. This

assessment is based on site visits in Japan between May 28 and June 5, 1990.

Key words: abrasives, adhesion, BN, bonding, boron nitride, chemical vapor

deposition, commmercialization, cubic boron nitride, cutting tools, CVD,

diamond, diamond films, diamond technology, diamond-like carbon, doping,

electronics, epitaxial growth, epitaxy, hard materials, heat conduction, heat

sinks, machine tools, nucleation, optics, physical properties, polishing,

thermal management

1
ACKNOWLEDGMENTS

We wish to thank Takayuki Shirao of the Science and Technology Agency, Office

of Materials Science and Technology for the invaluable assistance he provided

us in planning and implementing our visit. The visit was deemed to be very

worthwhile and his help assured the success of the trip.

We thank Dr. Asakura of the Rockwell International Overseas Corporation for

acting as translator and guide.

We wish to thank all of our Japanese hosts for the excellent hospitality and

courtesy extended to the members of our delegation.

The support of the National Science Foundation for the expenses of our university delegates was greatly appreciated.

We thank Ken Gordon of the NIST Office of International Affairs for his

assistance and advice, and Michael McCabe and R. Hyams of the State Department

for assistance with hotel arrangements in Japan.

We thank Verla Weaver of the National Technical Information Service for

organizing the debriefing seminar.

DISCLAIMER

The opinions expressed in this report are those of the authors of the report

and do not necessarily represent the views of the National Institute of

Standards and Technology, the Department of Commerce, or the Government of the

United States.

COVER DESCRIPTION

Microwave reactor for chemical vapor deposition (CVD) of diamond developed in

Japan at the National Institute for Research in Inorganic Materials (NIRIM)

.

2
FOREWARD

"Recent success in deposition of diamond and diamond- like coatings

on a variety of substrates at practical growth rates is one of the

most important technological developments of the last decade. It

places within the reach of science and industry an opportunity to

exploit many desirable extreme properties of these materials.

Indeed, the ultimate economic impact of this technology may

outstrip that of high temperature superconductors. Consequently

it is imperative that the United States take a leading role in the

commercialization of diamond technology."

Opening paragraph from STATUS AND APPLICATIONS OF DIAMOND AND DIAMOND -LIKE

MATERIALS: AN EMERGING TECHNOLOGY , published by the National Materials

Advisory Board of the National Research Council (NMAB-445, 1990)
CONCLUSIONS

1. Japanese companies have made a strategic commitment to support diamond

technology. They have committed to diamond technology without knowing exactly

what the markets will be. Small markets are seen at present, but larger

markets are expected to develop with the evolution of the technology. They

have faith that new applications will develop for a material with such

superior properties.

2. Diamond technology in Japan has grown beyond the need for governmental

incubation as evidenced by this industrial commitment. Many companies stated

that they do not receive and are not interested in government funding.

3. Japanese companies consider each other their main competition; however,

there is good communication among companies, except for information about

production technology.

4. The Japanese effort is directed predominantly to processing and

applications. In these areas the Japanese consider themselves to be ahead of

the United States. Most Japanese consider the United States stronger in basic

research; however, the results of basic research are rapidly disseminated and

serve all competitors equally, including companies in Japan.

5. It is probable that the United States trails Japan in production scale

capability with relatively few U.S. based manufacturers investing in this

technology. Several U.S. based companies appear ready to commit to an initial

product and it is likely that they have prototype systems with deposition

rates as high as those of Japanese companies. However, many more large

Japanese companies with a wider range of interests appear to have made such a commitment

.

6. Overall, the Japanese are leading in the new diamond technology. No

specific applications of diamond technology were identified in which the

Japanese have a dramatic advantage except high rate deposition of diamondlike carbon films. Announcements of commercial tool inserts made with

chemical vapor deposited (CVD) diamond suggest that they may lead in this

important application as well.

7. CVD diamond products are reaching the market sooner than high temperature

superconductor products and are likely to have a comparable ultimate economic

impact. In Japan, this has led to comparable investment in these two

developments by industry and government, while in the United States, a significant imbalance exists in R&D expenditures in favor of high temperature

superconductors

.

4
RECOMMENDATIONS

1. As part of its effort to support precompetitive research in support of

emerging technologies, government should significantly increase funding for

generic CVD diamond process development, for training facilities at

universities and national laboratories, and for internships for learning to use and apply the new diamond technology. This should include increases in

government funding for fundamental studies likely to be critical to future

technological development.

2. To be competitive, U.S. companies should significantly increase funding

for CVD diamond processing and applications. To facilitate these efforts, the

government should make companies aware of technology transfer opportunities

that exist at government and university laboratories, and should encourage

companies to take advantage of these opportunities.

3. An interagency committee to coordinate government funded R & D in CVD

diamond and related materials should be established by the Committee on Materials (COMAT) under the Office of Science and Technology Policy (OSTP)

.

Topics for immediate consideration by such a coordinating committee should

include

:

a. Support of several nationally recognized 'centers of excellence' in

CVD diamond and related materials research to ensure the development and

maintenance of a publicly accessible technology base in the United

States and identification of long term (>5 years) funding for these

centers

.

b. Exploration of mechanisms to enhance information transfer among

members of the U.S. diamond community.

c. Acceleration of translation of relevant Japanese journals and

patents

.

d. Encouragement and/or subsidization of closer United States -Japan

collaboration in diamond technology.

e. Development of calibration standards and standard measurement

methods for characterizing chemical and physical properties of CVD

diamond. Possible examples include standards for Raman spectroscopy,

optical quality, thermal conductivity, electrical conductivity, and

doping level (e.g., boron concentration).

4. The U.S. government should sponsor similar visits to assess Japanese

technology using the mechanism our delegation has established on the basis of

the 1988 United States -Japan Agreement on Cooperation in Research and

Development in Science and Technology.

5. While not specific to the current study, the committee recommends more broadly that the government should identify and eliminate those institutional

and structural impediments that make it unattractive for U.S. companies to

invest in longterm R&D.

5

U.S. ASSESSMENT OF THE NEW DIAMOND TECHNOLOGY IN JAPAN

INTRODUCTION

IMPORTANCE OF DIAMOND TECHNOLOGY

The properties of diamond make it desirable for numerous applications.

Diamond has several extreme properties, that is, properties with values

exceeding those of any other materials; these are hardness, thermal

conductivity at room temperature. Young's modulus, and free carrier saturation

velocity. Other important properties of diamond include low friction

coefficient, high chemical stability, low permeability to diffusion, high

x-ray transmission, high resistance to radiation damage, high electrical

resistivity, semiconducting properties with doping, high dielectric strength,

transparency to electromagnetic radiation from DC to the ultraviolet (except

for a small region in the infrared) , and high refractive index. It is the

combination of superior properties that make diamond such a desirable

material.

The areas of potential application are mechanical, thermal, electronic,

optical, optoelectronic, medical, and chemical. Within each of these areas specific applications include cutting tools, electronic substrates,

semiconductor devices, windows, ultraviolet detectors, prosthetics, and

chemically resistant containers. See the recent National Materials Advisory

Board report for a more detailed listing of potential applications .[ 1]

The development of chemical vapor deposition (CVD) methods to produce diamond

has now made it possible to consider diamond for all of those applications

that were previously inaccessable due to the limited sizes of previously

available diamond raw material or due to the high cost of the material. New

unforseen applications will arise with the expected wide availability of

diamond material in large sizes and at reasonable cost.

While projections for the sales of products made of diamond and other related

superhard materials [2] are very large (approximately $6B by the year 2000

[3]), these figures ultimately may underestimate the potential economic impact

that these materials can make. This is because the new diamond technology is an enabling technology which makes possible other technolgies. For example:

x-ray masks of CVD diamond may enable the production of larger scale

integrated circuits than would be possible without diamond; CVD diamond

substrates for integrated circuit packaging may enable a new generation of

high speed computers; and, inexpensive diamond tooling may enable new

production methods as well as new levels of production efficiency.

Although the scientific bases for CVD diamond deposition were discovered in

the U.S. and in the Soviet Union, it was in Japan at the National Institute

for Research in Inorganic Materials (NIRIM) that practical methods for

deposition of CVD diamond were developed. The hot filament [4] and the

microwave plasma [4] methods form the foundation of the new diamond technology

and it was the discovery of these diamond deposition methods that galvanized

the drive in Japan toward commercialization of CVD diamond. A sign of the

seriousness of the Japanese effort in CVD diamond technology was the formation

7
of the Japan New Diamond Forum (JNDF) in 1985, a consortium or trade

association of companies sharing a common interest in diamond technology. The

JNDF encourages active participation by government and university researchers.

It publishes New Diamond , a publication devoted entirely to the new CVD

diamond technology, and it sponsors technical conferences on this subject.

Belatedly, U.S. scientists and engineers recognized the significance of the

Japanese effort on CVD diamond. Some U.S. companies began efforts in CVD

diamond research and several new companies were formed to pursue CVD diamond

products. Sometimes the research occurred at the grassroots level, without

active management encouragement. In other cases, full scale development

projects were undertaken with full management support. At this stage it is

difficult to know whether U.S. industry has caught up to Japanese industry in

the drive toward commercialization. However, it appears that many more

Japanese companies are poised to exploit the technology.

Because of the potentially enormous economic impact the new diamond technology

is expected to make, it is important for the U.S. to seek a leadership

position in the commercialization of this technology. Technological

leadership in this arena will contribute significantly to the future economic

well being of this country.

BACKGROUND OF STUDY

This assessment was undertaken at the request of the joint committees for

implementation of the 1988 United States -Japan Agreement on Cooperation in

Research and Development in Science and Technology under the auspices of the

Committee on Materials, Office of Science and Technology Policy. The purposes

of the study were to assess the level of scientific activity, areas of

intended commercialization, progress in commercialization, the role of the

Japanese government in assisting industry to exploit the new diamond

technology, and the relative positions of Japan and the United States in all

aspects of synthesized diamond technology. Japanese efforts were chosen for

assessment because Japan is the apparent world leader in the drive for

commercialization of this technology. The principal focus of the study was

CVD diamond technology with a peripheral investigation of cubic boron nitride

(cBN) and diamond- like carbon.

The delegation, which was chosen from government, universities, and industry, was composed of experts in diamond technology and managers with a direct

interest in diamond technology. The researchers and managers we visited in

Japan at company, university, and government sites are leaders in the new

diamond technology. The visit to Japan took place between May 28 and June 5,

1990.

This report summarizes the findings of our committee. It discusses the status

in Japan of generic research, applications, manufacturing technology,

commericializaton and the role of the Japanese government. The discussion

includes information about cBN and diamond- like carbon research and products.

Our Conclusions and our Recommendations are presented at the beginning of the

report

.

8
Several appendices present details regarding our visit. Appendix A discusses

the planning and implementation of the assessment. In order to give a wider

perspective on the new diamond technology, a brief review of related work in

the rest of the world is presented in Appendix B. Reports describing the site

visits are given in Appendix C. Appendix D describes the administration of

science and technology in Japan. Appendices E lists the members of our delegation and Appendix F presents the biographies of the delegates. The

itinerary of our visit is given in Appendix G and the organizations visited

are listed in Appendix H. A listing of abbreviations is given in Appendix I.

In several parts of this report, monetary values are given. An exchange rate

of 150 Japanese yen (¥) per U.S. dollar was used, which was the approximate

rate of exchange during our visit.

REFERENCES AND NOTES

[1] Status and Applications of Diamond and Diamond-like Materials: An

Emerging Technology . Report of the Committee on Superhard Materials, National

Materials Advisory Board, Commission on Engineering and Technical Systems,

National Research Council (NMAB-445, National Academy Press, 1990).

[2] By superhard materials we refer to materials such as diamond,

diamond- like carbon and cBN.

[3] S. Kurita "A Summary of the Report of Studies on the Plausible Policies

for Promoting the New Diamond Industry," in New Diamond 1990 . M. Yoshikawa,

editor (The New Diamond Forum, c/o Tokyo Liaison Office, Japan Fine Ceramics

Center, & F Nishikan Toranomon Building, 1-22-13 Toranomon, Minato-ku, Tokyo

101 Japan) pp. 113-118.

[4] S. Matsumoto, Y. Sato, M. Kamo , and N. Setaka, "Vapor Deposition of

Diamond Particles from Methane , " Jpn. J. Appl. Phys . 21, L183 (1982).

[5] M. Kamo, Y. Sato, S. Matsumoto, and N. Setaka, "Diamond Synthesis from

Gas Phase in Microwave Plasma," J. Cryst. Growth 62, 642-4 (1983).

9

GENERIC RESEARCH

DEPOSITION TECHNOLOGIES

Introduction

The Japanese effort to advance the technology of diamond deposition from the

vapor phase is very impressive. Various new techniques and modifications to

established techniques are under development, although not always reported at

international gatherings. Many of these techniques are sometimes simple first

generation systems, but the concepts are technologically very creative and are continually opening up new areas of diamond research. It appears that the

most dramatic advances have been made at the government laboratories and at

universities, whereas more subtle advances have been made in the industrial

laboratories. It is quite probable that some of the most important industrial

advances were not openly discussed. However, it is interesting that the

university and government laboratory advances are very quickly transferred to

industry both through general and specific agreements. Three examples of such

transfers are the microwave plasma technique developed at the National

Institute for Research in Inorganic Materials (NIRIM) , the combustion

technique developed at the Nippon Institute of Technology, and electron

assisted CVD method developed at Aoyama Gakuin University, all of which have

been duplicated by numerous industrial laboratories. This innovation process

appears to occur more quickly and more often than in the United States

possibly because of the established collaborative technological interaction

between government, universities and industry. Thus, the research is much

more directly applicable to industrial goals.

There was a general impression during discussions with the Japanese in Japan

that Japan was significantly ahead of the United States in deposition method

technologies, but were probably behind the United States in the fundamental

understanding of the deposition process. The present section of this report

will attempt to summarize these technological advances and their impact on diamond technology, as well as to give an overview of the issues that appear

to be of greatest concern in Japan.

Cold Plasma Methods

Throughout our visits to the various laboratories conducting research and

development on diamond deposition, the impact of the initial NIRIM research

was evident. Many laboratories have sent researchers to study at NIRIM,

usually for periods of 3 to 6 months, and have installed NIRIM- type microwave

plasma CVD reactors which consist of a quartz tube placed perpendicularly

through a rectangular waveguide. Thus, historically, this type of microwave

system has had significant impact despite its limitations in deposition area,

growth rate, and film purity. It has also led to the development of microwave

reactors with different configurations that overcome some of these

limitations

.

The NIRIM type reactor has been utilized in many diamond deposition studies.

For example, it has been used to control surface morphology by modification of

deposition conditions, to enhance film quality by addition of oxygen to the

feed gas mixture, and to achieve doping with boron. However, the only

11
significant technological advance in deposition based directly on this

original configuration was observed by the conunittee at Kobe Steel. Three

NIRIM type microwave reactors were coupled together to allow for independent

depositions of pure diamond, p-type diamond, and n-type diamond on a single

substrate without cross contamination or autodoping. The sample may be

transferred from one chamber to the next without exposure to atmospheric

contaminants

.

A derivative technique based on the original NIRIM design involves coupling of

a rectangular waveguide to a cylindrical waveguide which acts as a resonant

cavity that allows for depositions over much larger areas. The cylindrical

waveguide either acts as the deposition chamber or is coupled to a separate

cylindrical deposition chamber. Idemitsu Petrochemical anticipates that 25 cm diameter depositions will be achievable with such microwave plasma techniques

by 1992. Kobe Steel showed the committee a microwave reactor of this type

capable of 10 cm diameter depositions. This reactor consists of two

rectangular waveguides coupled to one cylindrical chamber.

Osaka University is responsible for another significant advance utilizing

magnetically enhanced microwave plasma deposition. This system allows for

depositions over larger areas than most conventional systems. Due to plasma

confinement by a magnetic field, depositions can occur at lower than usual

pressures. However, this is not a true electron cyclotron resonance

deposition because the cyclotron resonance condition is not utilized. Two

systems are in operation. The newer system was a joint effort with Shimadzu

Corporation. This system has achieved diamond growth at chamber pressures as low as 0.01 Torr; however, the growth rate and film quality tend to be low.

The plasma area is fairly uniform up to 5 cm in diameter, although limitations

in substrate heating have prevented verification of uniform diamond

deposition.

Finally, the desire to achieve higher growth rates and better efficiencies has

led to research involving very high power input (tens of kilowatts) to create

thermal plasmas, which are discussed below. Microwave sources have not been

used in high power depositions due to unavailability of commercial sources at

reasonable cost. Currently, 5 kW is the maximum power easily obtainable from

a microwave generator and is typical of microwave powers utilized in reactors

being placed into operation. It is likely that higher power microwave

generators will become available in the future.

In Japan, cold radio frequency (RF) and direct current (DC) plasmas .rarely

have been utilized in diamond deposition according to the people in the

laboratories visited. This appears to be due to historical precedence rather

than to technical merit.

Thermal Plasmas and Combustion Synthesis

A new area of technological development receiving widespread attention in

Japan is diamond deposition with thermal plasmas. These are systems in which

plasmas are maintained by very high input powers resulting in electron and ion

temperatures that are approximately equal. Both RF and DC are used to

generate these plasmas.

12
The most impressive results utilizing thermal plasmas were observed at the

Tokyo Institute of Technology; a DC arc plasma jet was used to grow diamond at

a rate of 920 /im/hr. Although the deposition area was small, the efficiency

of gas use was claimed to be very high. Thus, the technique is expected to be

very cost effective. The heart of the system is a nozzle, equipped with a series of gas inlets, that allows for various input configurations of Ar, H2

,

hydrocarbons, and oxygen containing organic molecules. The entire system,

including the substrate, must be water cooled. This DC plasma jet is thought

to be more stable than the RF torch discussed below. However, electrode wear

introduces a low level of impurities into the films which is a concern for some applications. Such jets have also been utilized by Fujitsu and NIRIM.

Fujitsu has deposited diamond on areas 3 cm x 3 cm x 2 mm thick by scanning

the substrate under the jet. Growth rates in this case were greater than 200

/im/hr.

The other major thermal plasma technique observed was an inductively coupled

RF plasma torch at NIRIM. Deposition rates with this technique are about 200

/im/hr. The RF generator operated at a frequency of 4 MHz with a power output

in the range 10 kW to 50 kW. Gas mixtures of Ar, H2 and methane are utilized

at flow rates of tens of liters per minute. To avoid deposition on the side

walls of the chamber, a gas sheath containing hydrogen is employed.

Instabilities of the plasma, inefficiencies in power transfer, and nonuniform

depositions are the major concerns with this technique. However, the high

growth rates and potential for scale-up make it a very promising technique for

the commercial deposition of diamond.

A modification of the RF plasma torch technique, currently under development

at NIRIM, involves the use of variable RF frequencies. An RF generator with

power output believed to be between 70 kW and 100 kW and tunable between

15 Mhz and 100 Mhz is being installed. The higher frequencies are expected to

enable RF plasmas to be stably maintained without the use of Ar in feed gas

mixtures. When this system is completed, it should provide additional insight

into the growth of diamond from high density thermal plasmas.

Combustion synthesis of diamond is receiving increased attention in Japan.

Combustion synthesis provides a similar environment for diamond growth as hot

plasma sources. This technique was developed at the Nippon Institute of

Technology (NIT) and is now being examined in numerous laboratories, including

Showa Denko, Kobe Steel, and NIRIM. This is probably due to the simplicity

of the method and the small cost for its implementation. The major obstacles

that must be overcome in combustion synthesis are the small growth areas which

are about 5 mm x 5 mm and the nonuniformity of growth. To improve the

uniformity and increase the area of deposition, NIT is working on a system to scan the flame over the substrate. Showa Denko has developed a low pressure

combustion flame system that is enclosed in a chamber. Using this method,

they have increased the growth area to approximately 9 x 9 mm, but uniformity

still remains a problem.

One advantage for the combustion synthesis of diamond is the large volume of

background information about combustion flames that is available. Much of

this information predates the development of low pressure diamond synthesis.

Thus, the study of combustion synthesis of diamond rests on a foundation of

scientific knowledge and measurement techniques which can be applied to

13
optimizing the process. For example, NIT is utilizing emission spectroscopy

to understand the growth environment.

The combustion flame method has two other problems that will impede its

commercial use. First, the cost of the feed gas is high because the

combustion process consumes the hydrocarbons; recirculating the hydrocarbons

is not feasible. Second, the thickness of films is limited to about 200 /im,

presumably due to substrate temperature effects. No significant solutions to

these problems were observed by the committee.

Hot Filament CVD (HFCVD)

Most Japanese laboratories have worked with HFCVD to some extent, although

some believe it may not be feasible for commercial production. Major advances

in this area have involved increased growth area, growth rate, and film

quality. Aoyama Gakuin University has shown that electric field biasing

enhances growth rate and this concept is being pursued by Sumitomo Electric,

Kobe Steel, and probably others. New systems appear to use a high electric

field biasing deposition process that combines features of hot filament and DC

plasma deposition. If growth parameters are properly optimized, such a combination appears to improve film quality and increase growth rates

simultaneously. NIT was the first to show that feed gases containing various

organic compounds, especially alcohols, also enhance the growth rate and film

quality. Perhaps the most interesting new result was observed at Sumitomo

Electric where the deposition area appeared to have been increased to as large

as 10 inches square by using multiple filaments made of long wires. Sumitomo

also stated that this and other systems were run continuously for numerous

days in order to achieve thick films for various applications. NEC has also

constructed a similar large area HFCVD system. Both the NEC and Sumitomo

Electric systems utilize a tensioning system to keep the hot filaments from

sagging during growth.

Another interesting advancement in HFCVD was the coating of nonflat surfaces

at Showa Denko . Researchers were able to coat the inside of a crucible by

conforming a filament to the approximate cross -sectional shape of the crucible

and then rotating the crucible to obtain dome shaped diamond films for speaker

diaphragms. Free-standing diamond cylinders and disks were also observed at

Showa Denko

.

Miscellaneous

The use of carbon monoxide instead of methane in the feed gas enhances

deposition rates by a factor of ten in conventional microwave plasma CVD

reactors. Idemitsu Petrochemical claims to hold a patent for this process.

Idemitsu will identify other additives that aid diamond growth at an upcoming

professional meeting.

At Aoyama Gakuin University, two interesting deposition results have recently

been reported. The first is the heteroepitaxial growth of diamond on cubic

boron nitride (cBN) crystals as verified by electron diffraction and Raman

spectroscopy. Although the cBN crystals were small (100 /xm sized crystals

prepared by the high temperature/high pressure process) and thus not

commercially viable, this work proves that heteroepitaxial growth of diamond

is possible. Second, small diamond particles have been grown from carbon

14
evaporated by an electron beam coupled with a molybdenioni cracker. Results

were interpreted as indicating the importance of a C^^ species for the growth

of diamond.

An interesting advance in the growth of diamond powder was reported by Showa

Denko . A crucible containing a fluidized bed of ceramic powder was placed in

a hot filament reactor to allow the ceramic particles to be coated with

diamond. Cross sectional images of the particles revealed the success of this

technique. Fluidization of the particles was maintained by vibration of the

crucible. By varying the deposition parameters, the surface morphology could

be accurately controlled to be cubo - octahedral , mirror-ball, or rounded ball.

A problem of concern to commercialization of diamond is adhesion. NIT has

developed an apparatus to measure adhesion of diamond to a substrate by

measuring the displacement of a hard wedge placed at the diamond/substrate

interface as a function of the applied load. However, there was minimal

information about how the problem of adhesion was being addressed, presumably

due to its proprietary nature. Toshiba-Tungaloy indicated that surface

pretreatment of cobalt free sintered tungsten-carbide permitted deposition of

adherent diamond coatings. The reliability of these coatings was not

discussed. Several pretreatments , especially those to decrease surface cobalt

concentration in sintered carbide substrates, or the use of interfacial layers are gradually yielding successful results.

It now appears relatively routine to control surface morphology from smooth

with microcrystalline grains to rough with large-grained polycrystals . Even

the type of faceting [(100) vs. (Ill)] can be chosen, depending on growth

conditions . Scanning electron microscopy remains the primary technique for

observing such surface morphology while Raman spectroscopy is used for

determining diamond film quality.

Several companies (including Fujitsu, Kobe Steel, Ltd., and NEC) are conducting their diamond depositions in a clean room, possibly in anticipation

of commercialization in the future.

An interesting observation about patents related to growth techniques should

be noted. Many companies are working on techniques that have been patented in

their fundamental form elsewhere; however, the investigators do not believe

that patent infringement will be a problem. It was stated that the patent

problem will be addressed as products approach the commercialization stage.

Some companies felt that they had made significant modifications that will

allow them to obtain their own patents. Others stated that they would

cross -license the desired technology. Obviously, numerous companies will

require licensing of the original NIRIM patents; however, there appears to be

some disagreement regarding how encompassing the NIRIM patents are. Some

companies believe their techniques do not fall under these patents, but these

views may be challenged.

Summary

Laboratories in Japan are quite advanced in the technology of diamond film

deposition. New approaches and modifications to existing technology continue

to be developed by the leading laboratories. The United States appears to

lead Japan in fundamental investigations and understanding of the deposition

15
process, but lags in diamond deposition technology, especially in the high

growth rate techniques. Gas species analysis is of interest to many

laboratories in Japan, but measurement techniques are less advanced than those

used in the United States Low temperature deposition may be one area in which

the United States has a significant advantage at the present time. The

Japanese can control surface morphology and film roughness, but adhesion

remains a major concern. However, advances in adhesion have allowed prototype

cutting tools to be marketed. (Since our visit. Dr. Kawarada of Fujitsu has

reported that adhesion can be controlled at his company.) The

state-of-the-art in deposition area appears to be somewhere between 15 cm diameter disks and 10 x 25 cm plates, although the ability to achieve these

dimensions is limited to two or three laboratories.

Most Japanese companies with a significant effort in diamond have >i approximately 10 deposition systems in operation and have experience with

several different deposition techniques. The initial work of NIRIM, which

spawned this field in the early 1980s, still has a significant impact on current research. The microwave plasma technique seems to be the method of

choice for controllable, high quality, pure diamond depositions that can be

monitored for process control. Hot filament deposition appears to be the

leader in terms of growth area, but within the next two years it is expected

that microwave plasmas will be very competitive. Microwave plasma and HFCVD

are limited to low deposition rates, but can be run continuously over long . periods of time to achieve thick films.

The Japanese are rapidly gaining experience in the use of thermal plasma

techniques for depositing diamond at high deposition rates. DC plasma jets

and RF plasma torches have been the primary advances, but these methods are have limited deposition areas. Scanning the substrate in the deposition

region is one method that allows for increased growth areas, but this method

has not yet been fully developed. The DC plasma jet appears to have the

greatest economic efficiency of all the deposition methods. Economically

efficient diamond growth appears to be a goal of several research groups.

Most of the systems observed were not commercially available, but were custom

built, sometimes through collaborations between universities and industry.

Commercially available systems targeted specifically for diamond growth are now becoming available.

NUCLEATION

There is a recognition by Japanese research groups, as in the United States,

that control of nucleation is essential for many applications. The Japanese

effort in control of nucleation and progress being made appear to be similar

to that in the United States. For example, substrate pretreatment with

diamond powder or other abrasives is necessary to promote nucleation in

microwave and hot filament reactors. Nucleation promotion is not required

with the high deposition rate thermal plasma or combustion methods.

Some Japanese groups are taking fundamental approaches to the nucleation

problem. Yoichiro Sato and his colleagues at NIRIM are developing a capability for fundamental in situ surface science studies during nucleation

and growth. This work has a high probability of unraveling some of the

16
complexities of nucleation and growth mechanisms. Seiichiro Matsumoto, also

at NIRIM, is explicitly studying homogeneous nucleation processes in diamond

chemical vapor deposition. Matsumoto was the first to propose high molecular

weight compounds as the precursors to diamond formation. Few details of his

current work are available.

At Matsushita Electric, silicon surfaces are being implanted with carbon as a pre treatment for subsequent diamond nucleation and growth. Details of the

process and specific results were not available. Also, several Japanese

groups are nucleating and growing diamond on nondiamond substrates within

fluidized beds. Silicon carbide particles are being used as seed crystals in some of these experiments

.

One important goal of diamond research in the United States is heteroepitaxial

deposition of diamond over large areas. We observed no evidence for

successful large area diamond heteroepitaxy in Japan. Several Japanese

laboratories are working in this research area.

A particular advance in diamond nucleation should also be noted. Osaka

University, Kobe Steel, and Canon Inc. have used a photolithographic technique

to deposit diamond on selected areas of a substrate while leaving the

remaining substrate area diamond free. This technique, called SENTAXY,

employs an ion beam to damage a selected region of the substrate surface,

preventing nucleation of diamond in the damaged region. The technique has

been used at Kobe Steel to fabricate various circuit elements made of diamond,

such as thermistors and Hall effect devices. This selective area deposition

technique also may help us gain insights about the mechanisms for diamond

nucleation.

CHEMICAL AND PHYSICAL PROPERTIES

Specifications for physical and chemical properties of diamond depend on the

application for which the material is intended. After a practical set of

specifications has been defined, direct measurements must be made to confirm

that the material complies with the specified properties. Such qualifications

of CVD diamond requires not only reliable measurement methods, but also

appropriate protocols for executing sequences of complementary

characterizations that examine the interdependence of physical and chemical

properties. Since the important chemical and physical properties of CVD

diamond can vary considerably with growth parameters, exact knowledge of and

control of growth conditions are imperative. Parameters such as feed gas

composition, feed gas flow rate, deposition pressure, substrate temperature,

filament temperature, filament geometry, plasma temperature, and plasma

electric field strength can influence deposition rate, morphology, grain size,

hardness, surface roughness, thermal conductivity, electrical resistivity,

film adhesion, color, optical transparency, sp'^ to sp^ carbon level ratios,

and impurity content. Consequently, only by detailed characterizations of

deposited films and definitive correlation of measured properties with growth

conditions can films be tailored reproducibly for specified properties.

Measurement techniques for determining specified properties of diamond are as well developed in Japan as in the United States. In both countries there is a need to systematize the characterization of diamond to ensure that

17
investigators use a universal protocol for determining physical properties

such as thermal conductivity, hardness, resistivity, thickness, adhesion,

stress, and surface roughness. While chemically related measurements such as Raman frequencies, NMR chemical shifts, hydrogen content etc., can be easily

compared, few investigators report accurate and reproducible physical property

measurements that permit interlaboratory comparisons. A need continues to

exist for investigators to establish a specification for combinations of

measurement techniques that totally characterize a diamond specimen for a specific application. The data from such characterizations are likely to be

retained as proprietary information. However, these measurement protocols are critical for the technical exploitation of diamond.

Chemical properties

The identification of a material as diamond is based largely on the

characteristic Raman vibration at 1332 cm" ^ . This is the most widely used

confirmation tool, which also indicates the purity of the deposited films with

respect to sp^ contaminants. Several Japanese laboratories, for example

Fujitsu, have also used NMR for characterization of CVD diamond. Diamond has

a well defined resonance peak with a chemical shift of 35 ppm relative to the

standard carbon reference, tetra-methyl-silane . Three-fold coordinated

(aromatic or graphitic) environments have chemical shifts in the 70 to 150 ppm

range and are readily distinguishable. Thus NMR spectroscopy can provide a quantitative breakdown of the carbon bonding environments in both diamond and

diamond-like material.

The measurement of the hydrogen content in diamond materials is also important

to correlate with property measurements. This is especially true for

diamond- like carbon (DLC) where it is important to correlate hydrogen content

with density. Matsushita Electric has prepared DLC with a density of 1.8

g/cxt? , a hardness of 2800 Kg/mm^ , and containing less than 5% hydrogen. The

hydrogen content was determined by an unnormalized SIMS techniques.

Hydrogen in DLC has also been measured by Rutherford backscattering (RBS) and

by recoil methods at NEC. DLC films containing 24% to 32% hydrogen had been

fabricated. Detailed thermal decomposition studies at NEC showed that the DLC

films lose CH3 and CH2 groups as the temperature is raised above 200 °C. At

400 °C the films begin to graphitize and at 430 "C they become unstable. DLC

films prepared by glow discharge showed high electrical resistivity of

2.8 X lO^'' ohm-cm, a dielectric constant of 3.5 and densities of 2 g/crn^ . The

location of hydrogen in diamond still remains an unresolved question. Does it

reside predominantly at the grain boundaries or within the crystal structure?

At Seiko Instruments Inc., Akira Nishikawa [1] showed a significant

correlation between the Raman spectra of diamond films deposited by microwave

plasma CVD, the methane/hydrogen ratios used in the feed gas and thermal

conductivity. This work had been reported previously by Ono et al.[2]. The

sharpness of the diamond Raman peak showed a correlation with increasing

thermal conductivity, and an anticorrelation with increasing methane/hydrogen

ratio

.

At the Semiconductor Energy Laboratory (SEL) , the electron cyclotron resonance

(ECR) process for diamond deposition has been optimized by use of atomic

emission spectroscopy. Control of the levels of atomic hydrogen during growth

18
has been accomplished. By inserting a light probe into different regions of

the ECR discharge, SEL has determined the parameter space in power, pressure,

and substrate bias whereby one can obtain uniform 656 nm atomic hydrogen

emission over a 100 mm diameter wafer. This is an example of the high quality

engineering characterizations performed at SEL [3].

At NEC, the dependence of surface roughness of films on the methane fraction

in the feed gas was studied by SEM examination. At methane fractions of 1%,

rough faceted growth was observed. Increasing the methane fraction to 3% gave

significantly reduced surface roughness due to the decreased size of the

diamond crystallites. These films, which were 5 /xm thick, were translucent

and had a thermal conductivity of 500 W/m/K. Films were characterized by

Raman spectroscopy and x-ray diffraction. Morphology, roughness and

transmittance were also assessed.

Another valuable measurement process was claimed by Asahi Diamond. While no details were provided, they indicated that it was using in situ thickness

monitoring of diamond film growth.

Physical Properties

Many Japanese companies have made significant investments in characterization

methods for supporting their diamond programs. Facilities are available for

determining nucleation density, hardness, thermal conductivity. Young's

modulus, and resistivity. Analytical techniques include, scanning electron

microscopy, reflection high energy electron diffraction (RHEED) , ESCA, Auger

spectroscopy, cathodoluminescence , optical spectroscopy, transmission electron

microscopy, x-ray diffraction, NMR, Raman spectroscopy, and Rutherford

backscattering

.

Determinations of the thermal conductivity or thermal diffusivity of

polycrystalline diamond are made by relatively few laboratories. The radiant

cooling method was developed by Seiko in collaboration with the National

Research Laboratory of Metrology. This approach described by Akira Ono and

co-workers measures the thermal conductivity of thin films (7 to 30 fim) in a direction parallel to the surface [2]. Measurements are made between 100 °C

and 130 °C by a thermograph providing a visual display of temperature

distribution along an unsupported diamond film in the form of a thin ribbon.

Samples of oxygen- free copper and pure silver were used to calibrate the

apparatus to an accuracy of several percent. Some difficulty was experienced

with fracture of unsupported diamond films during measurements. Thermal

conductivity of diamond films versus methane/hydrogen ratios in the feed gas

showed an inverse relationship. Films prepared at 0.1 methane fraction had

the highest thermal conductivity, 1000 U/m/K. The thermal conductivity

decreased rapidly with increasing me thane/hydrogen ratios. Thermal

conductivity also showed an inverse correlation with graphitic or DLC content

in the films as indicated the Raman spectra. Similar studies of thermal

diffusivity versus methane/hydrogen ratios have been done by NEC. The AC

calorimetric instrument used by NEC to measure thermal conductivity is

available commercially [4]

,

Stress is another important property that must be controlled in diamond film

preparation. This is especially important in the production of diamond

membranes for x-ray lithography. Direct measurements of stress were not

19
widely reported during our visits. Only one group, at Tokyo Institute of

Technology, is examining the influence of microwave power on stress in the

films. The change of stress in the deposited material is determined by shifts

in the characteristic Raman peaks for diamond.

Other physical measurements are useful for characterizing diamond films. For

example, density measurements provide information about the relative content

of non- diamond components in the film. Density measurements are not commonly

performed because the measurement method employed uses liquids that have toxic

properties

.

ADHESION, BONDING AND HARDNESS

The strength of the adhesive bond of diamond films to the substrate is a very

important property for many applications. For diamond cutting tool inserts

this is the most important property. Only limited information on adhesion and

bonding was provided by our Japanese hosts. Detailed scrutiny of Japanese

patents may be needed to obtain more information about their progress in these

proprietary areas.

Adhesion of diamond received the most attention from corporations interested

in exploiting diamond as a cutting tool material. Although Fujitsu listed the

development of the methods for improving the adhesion of CVD diamond to

substrates as a major accomplishment over the past year, details on how this was accomplished were not provided. Adhesion of diamond as a function of

substrate thickness was shown by Professor Tadao Inuzuka at Aoyama Gakuin

University. Diamond adhesion to a given substrate as a function of film j thickness is also important, but no information about this measurement was .;; revealed during our visits.

Researchers at Idemitsu Petrochemical indicated that they were not successful

in preventing the delamination of CVD diamond from the surface of tungsten

carbide. Close examination revealed that WC and diamond had a strong bond,

but fracture occurred during use of the tool bits due to the disparate thermal

expansion between WC and diamond. By using SigN^ , a material whose thermal

expansion closely matches that of diamond, instead of WC, excellent adhesion

of diamond was obtained.

Kobe Steel has fabricated CVD diamond coated WC-Co tool inserts in a microwave

plasma. However, the adhesion was believed to be insufficient for marketing a practical product. In contrast, Mitsubishi Metals reports the direct coating

of diamond onto specially prepared cemented carbide inserts. Adhesion

problems have been largely solved by control of the cobalt layer and by proper

surface treatment methods [5]. Toshiba Tungaloy has also improved the

adhesion strength of diamond to WC by eliminating the use of cobalt. The

surface is first roughened before diamond deposition. Decarbonization is then

achieved by etching the surface in a 2% 0^ in H2 microwave plasma. Electron

micrographs of the treated surface indicate that the surface morphology of the

WC influences adhesion. X-ray diffraction results indicate that the treated

surface is very fine grained compared to the untreated one. The surface after

plasma etching is also rich in metallic tungsten. TEM micrographs of the

interface indicate that good adhesion is due partly to filaments of WC

interwinded with diamond.

20
The most definitive experimental measurements of adhesion were detailed at

Toshiba Tungaloy and at the Nippon Institute of Technology. At Toshiba

Tungaloy, the results of a 60 kg drop weight and scratch test were used to

examine the hardness and adhesion of diamond to the WC interface. Although

the wear resistance of the diamond is excellent, adhesion strength still needs

further improvements. As mentioned earlier, a lateral scraping device was demonstrated for measuring film adhesion, at NIT. A unique shearing wear

tester was developed in-house. This machine measures the rate of wear of a diamond cutting edge by repeatedly cutting slivers of carbide abrasive tape.

This instrument has been used to demonstrate quantitative correlation between

film adhesion and cutting edge lifetime.

At NEC a micro- indenter method has been applied to determine the hardness of

DLC [5] . The distance of penetration of a loaded microtip was measured by

measuring interference fringe movement as a function of applied load with an electrobalance . Both the hardness and Young's modulus of the diamond films were determined by comparison with measurements performed on materials with

known hardness used as reference standards.

DOPING OF DIAMOND FILMS

Idemitsu Petrochemical, Osaka University, Sumitomo Electric, and Kobe Steel

have active research programs in doping of diamond films. Sumitomo Electric

is working on doped homoepitaxial diamond films . These are doped CVD diamond

layers deposited on single crystal diamond substrates. All of the

laboratories are doping and characterizing polycrystalline diamond films. No

work was being done on doping diamond at NIRIM because of their emphasis on first understanding undoped diamond. NIRIM expects to begin working on doped

diamond films soon.

Kobe Steel probably has the largest investment in equipment for the

development of polycrystralline diamond device technology. The work at Kobe

Steel is based on microwave plasma deposition; their deposition system has

been described above. Boron is the dopant of choice, and prototype Hall

devices are being fabricated to determine carrier concentrations and

mobilities. Secondary nucleation of the doped diamond on the undoped layer

has been avoided by initiating a hydrogen discharge prior to introducing the

methane for the doped diamond deposition.

Osaka University has been doping SYNTAXY produced diamond films with boron.

Doping was accomplished by use of B2Hg in the feed gas with concentrations not

exceeding 1000 parts per million (ppm) . Exceeding 1000 ppm resulted in

degradation of the diamond quality. Nitrogen, introduced as Ng in the feed

gas, is being tested a dopant source. Electron spin resonance is being used

to measure the nitrogen concentrations in the films.

Idemitsu Petrochemical has been studying the electrical conductivity of

B-doped diamond films as a function temperature at different doping levels.

The conductivity is measured over the temperature range 300 to 650 K on films

grown on (111) diamond substrates.

21
Sumitomo Electric reported significant information on dopant incorporation in

homoepitaxial films. B, S, P, CI, As, and Se were evaluated as dopants.

Phosphorous doping did result in n-type behavior but the conductivity of the

films was very poor. The activation energy of the boron doped samples was observed to be a function of the dopant concentration in the gas phase. Table

1 gives values for the activation energy for various boron gas concentrations

for homoepitaxial growths on (100) growth surfaces.

The boron concentration in the (100) films was determined by SIMS analysis.

The results are shown in Table 2.

The hole mobility as a function of temperature was reported for one of the

boron doped films. The hole concentration at room temperature was 10^ •'cm''' increasing to 10^°cm'^ at 600 "C. The hole mobility at room temperature was

960 cm^/V/s declining to 70 cm^/V/s at 600 °C. Sumitomo has fabricated some devices from B- doped films.

TABLE 1. Carrier activation energy vs. boron concentration in the feed gas

for diamond films deposited on diamond substrates [6]

Substrate orientation carrier activation energy

(100)

(110)

boron concentration in feed gas

20ppm lOOppm lOOOppm

0.43 eV

0.43

0.34 eV

0.35

0.22 eV

0.11

Table 2. Boron concentration in deposited diamond films vs boron fraction

in the feed gas [6]

B in feed gas (ppm) 40 100 1000

Boron concentration

in film (cm' ^

) 4.0 X 10^^ 6.0 X 10^^ 1.0 X 10^0

DIAMOND EPITAXIAL GROWTH

Few Japanese companies or universities appear to be involved in diamond

epitaxial growth. This is probably because the Japanese are interested in

processes that are expected to produce more immediate practical results and

22
polycrystalline diamond films may suffice in some electronic applications.

The most notable exception is Sumitomo Electric where considerable research in

the growth of homoepitaxial diamond films has been performed. This is

probably because Sumitomo's capability to produce high pressure diamond

substrates allows its researchers to select, cut and polish high quality

substrates for epitaxial growth. This capability gives Sumitomo a significant

advantage in CVD homoepitaxial studies.

Sumitomo uses microwave systems of its own design for diamond growth.

Microwave reactors are preferred over hot- filament reactors for the growth of

epitaxial layers because of impurity incorporation during the hot filament

process ; 20 to 30 ppm of W have been found in diamond films grown in

hot-filament reactors. The microwave systems operate at pressures between 40

and 100 Torr using methane/hydrogen mixtures. The highest quality diamond

growth is found to occur on (100) diamond surfaces at a substrate temperature

of 830 °C and with a surprisingly high methane fraction (6%) in the feed gas.

This assessment was made on the basis of surface topography examination, RHEED

analysis, and Raman spectroscopy. The homoepitaxial films deposited with 6%

methane had smoother surfaces and contained less amorphous carbon bonding than

films deposited with lower or higher methane fractions in the feed gas.

Besides homoepitaxy, Sumitomo also showed results on the heteroepitaxial

growth of diamond on high-pressure synthesized cBN crystals. RHEED data was shown for heteroepitaxial growth on both (111) and (100) faces of cBN. Details

of the growth were not given and no characterization methods other than RHEED were mentioned.

Workers at Aoyama Gakuim University have also grown diamond on cBN. Professor

Inuzuka has imbedded cBN crystals into Ta and has studied the growth of

diamond on various faces of the cBN. The films grown on the cBN crystals are under considerable stress as evidenced by the shift in the diamond Raman line

from 1332 cm" ^ to 1325.6 cm' ^ . After depositing 10 /im, a smooth (111) diamond

film was obtained.

A variety of substrates are being tested for heteroepitaxy by different groups

in Japan. These substrates include MgF2 , MgAl2 04 , AlN, SiC, CaF2 , and AI2O3

.

Only the work on cBN has been successful.

POST DEPOSITION PROCESSING

Most applications for CVD diamond require some form of processing of the

deposited material. In this report, post deposition processing is taken to

include, polishing, etching, and brazing. Many Japanese companies realize

that these technologies are essential in applications of CVD diamond, and have

devoted considerable resources into these areas.

To illustrate the enabling nature of post deposition processing, consider a CVD diamond film with a surface roughness of 1 to 3 /xm; it will be unsuitable

as an optical window material due to optical scatter. Similarly, the surface

roughness of CVD diamond films can limit their use as heat sinks and

tribological coatings due to poor thermal contact and sliding friction,

respectively. Polishing offers a way of reducing surface roughness, and

thereby enables optical, heat sink, and tribological applications of CVD

23
diamond. An alternate approach to reducing surface roughness Is to synthesize

the CVD diamond with controlled, small (relative to the wavelength) , uniform

grain size, independent of film thickness. Modifying the as -grown properties

of CVD diamond films will be discussed in later section.

Laser cutting and planing VLasers are routinely used to cut diamond synthesized with high pressure/high

temperature techniques. Recently, Tezuka and Yoshikawa at the Tokyo Institute

of Technology reported using a Nd:YAG laser to cut and plane diamond films

grown with a DC Plasma Jet [7]. Their technique uses a repetitively pulsed

Q- switched Nd:YAG laser with a peak power of 23 kW and a pulse repetition rate

of 1 kHz. An oxygen atmosphere was needed to remove the graphite (through

conversion to CO2 ) which accumulated during laser irradiation. The planing

operation begins with a focussed laser beam aligned approximately parallel to

the surface of a diamond film. The beam is then traversed at a Imm/sec rate across the surface. The focus is gradually advanced along the beam direction

and down into the film with successive passes. Roughness averages of 3 fj,m have been achieved. Cutting of diamond films deposited by plasma jet was

also demonstrated.

Ion etching processes

Etching of diamond films has been studied at Kobe Steel, at NIRIM, and at

other institutions. At Kobe Steel, etching has been accomplished in a specially tailored DC plasma discharge containing oxygen and helium between

parallel electrodes. Etch rates between 1 and 2 fim/hr have been achieved.

The NIRIM work used an oxygen plasma in a microwave reactor to reveal the

columnar structure of microwave plasma synthesized CVD diamond films. Work in

smoothing CVD diamond films with a Penning discharge micro- sputtering system

was recently reported by Seiko [8] . Their procedure uses an Ar/02 plasma at

0.001 Torr for reducing the surface roughness of CVD diamond films. They have

achieved etching rates of 0.07 mm/min.

Chemical polishing

Numerous groups in Japan are researching chemical and abrasive techniques for

polishing CVD diamond. Yoshikawa at the Tokyo Institute of Technology (TIT)

has developed a novel technique for polishing CVD diamond which is based on

the poor performance of diamond tools when cutting and grinding ferrous metals

[9,10]. His technique places the CVD diamond sample on a hot iron surface

rotating near a tungsten filament in a hydrogen atmosphere. The standard

operating conditions are: iron plate temperature, 700-900 °C; filament

temperature, 2000 °C; hydrogen flow rate, lOOsccm; chamber pressure, 40 torr;

rotation rate of iron plate, 5 rpm (the sample was also rotated about its

center at a slower rate); and pressure of sample against iron plate, 60 kPa.

To obtain a peak to valley surface roughness of between 2 and 3 required 4

hr of polishing under these conditions, giving a material removal rate of

about 0.5 fim/hr . Yoshikawa indicated [11] that the mechanism for polishing is

diffusion of carbon into the iron to form a carbide, and subsequently removal

of the carbon from the iron surface by methanation. Recently, Yoshikawa has

observed polishing in vacuum environments, polishing rates of 6 ^m/hr, and

preliminary evidence of polishing (111) faces of natural diamond with this

technique [ 12 ]

.

24
Showa Denko is working with Dr. Murakawa at the Nippon Institute of Technology

(NIT) on a very similar process which can produce a surface roughness of

0.01-0.05 ftm in 10-20 min. ; Showa Denko has applied for a U.S. patent on this

process. Fujitsu and other Japanese companies have set up systems similar to

Yoshikawa's and are beginning to use this technique for polishing CVD diamond.

Abrasive polishing

Several groups in Japan are studying more conventional abrasive polishing

techniques for CVD diamond. At NIRIM, a low speed cast iron wheel impregnated

with diamond grit has been used to polish a microwave plasma grown diamond

film to a specular finish in the visible. The polishing took many hours to

complete. Osaka Industrial Diamond Company has used a diamond wheel to polish

fairly large area CVD diamond films (1x2 cm) to a specular finish in the

visible. The polishing rate was reported to be very fast. Thick (100 ^m)

diamond films were polished at Sumitomo's research laboratory by conventional

abrasive techniques.

Brazing

While brazing appears to be the technique for fabricating the first generation

of CVD diamond tools, we did not observe any research related to brazing.

Sumitomo is manufacturing a small end mill cutter and a TAB bonder by brazing

thick CVD diamond coatings to the underlying support material. Cutting tests

observed at NIT were being performed with a brazed CVD diamond insert. Asahi

Diamond claims to have patented a superior brazing process for CVD diamond.

Brazing produces a more reliably adherent CVD diamond coating compared to

direct CVD diamond deposition onto a substrate.

25
REFERENCES AND NOTES

[I] A. Nishikawa, "Measurement for Thermal Conductivity of Diamond Films",

in New Diamond . Japan Reviews in New Diamond 1990, Japan New Diamond Forum,

pp. 70-72.

[2] A. Ono, T. Baba, H. Funamoto, and A. Nishikawa, "Thermal Conductivity of

Diamond Films Synthesized by Microwave Plasma CVD," Jap. J. Appl. Phys . 25,

1986, pp. L 808-L810.

[3] See Appendix C, site visit report for Semiconductor Energy Laboratory,

p. 65.

[4] I. Hatta, Y. Sasuga, R. Kato, and A. Maesono, Rev. Sci. Instrvim. , 56,

1643 (1985) .

[5] S. Hoshino, K. Fujii, N. Shohata, H. Yamagucki, Y. Tsukamoto, and

M.Yanagsawa, "Mechanical Properties of Diamond-like Carbon Films," J.

Appl. Phys., 65, 1918-1922 (1989).

[6] N. Fujimori, H. Nakahata, and T. Imai, " Proper ites of Boron- Doped

Epitaxial Diamond Films," Jpn. J. Appl. Phys. 29, 824-827 (1990).

[7] S. Tezuka and M. Yoshikawa, "Cutting and Surface Planing of CVD Diamond

Films by YAG Laser," New Diamond 17, 36 (1990) [in Japanese].

[8] H. Funamoto, 0. Koseki , T. Sugita, Y. Yoshida, and E. Nishikawa,

"Planing of Diamond Film by Penning Discharge Micro-etching," Spring Japanese

Applied Physics Meeting, Program and Book of Abstracts, p. 27, p-E-12 (1990).

[9] C.F. Yang, H. Tokura, and M. Yoshikawa, "Polishing of Diamond Film With

Metal," Program and Book of Abstracts, 1st International Conference on the New

Diamond Science and Technology (Tokyo, 1988) p. 138.

[10] M. Yoshikawa, "CVD Diamond Film Polishing," in SPIE Proceedings Vol.

1325 - Diamond Optics III (1990), pp. 210-221.

[II] M. Yoshikawa, "Applications for Mechanical Characteristics" Diamond Thin

Film Technology, Ch. 6 (in Japanese), N. Setaka, editor (Sogo Gijutsu Center,

1988)

.

[12] Personal communication, M. Yoshikawa, May 1990. Yoshikawa also

indicated that the higher polishing rates were obtained without a filament and

with an iron temperature of 900 °C.

26
APPLICATIONS

INTRODUCTION

The market for CVD diamond and DLC products is not well defined yet; however,

Japanese companies are focussing on several main applications including

machine cutting tools, tool coatings, TAB bonding tools, electronic devices,

heat sinks (thermal conductors), and optical windows and coatings. Many large

Japanese companies have research and development efforts on CVD diamond of

between 5 and 15 researchers, with significant equipment capitalization

programs. Although mass produced CVD diamond products are not expected in the near future, companies seem willing to devote significant resources to develop

technologies for patenting, commercial products, and in-house expertise. Due

to the rapidly accelerating pace of scientific research in this field, any

report on applications of CVD diamond is bound to be dated. It is also

expected that new discoveries will fuel new applications and markets, and that

the focus of research teams may shift to accommodate these changes . Companies

with an in-house capability to synthesize, process, and characterize CVD

diamond will be most able to adapt and respond to new developments in the

field.

The following sections of this report discuss Japanese CVD diamond research

efforts in the following areas: machine tools and abrasives, heat sinks

(thermal conductors), semiconductor applications, and optics. Little or no research was observed on wear coatings, chemically protective coatings, and

masks for x-ray lithography.

MACHINE TOOLS AND ABRASIVES

Almost all of the products common to industrially developed nations require,

at some stage of their fabrication, various machining and surface finishing

operations. Examples include dimensioning and planing of lumber for the

construction industry, surface milling of engine and transmission components

in the automobile industry, and finishing and polishing computer disc drive

read/write heads for the computer industry. It is generally recognized that

material removal operations form a substantial part of the processing

technology base for a modern industrial economy. No less important is the

control of wear and friction. Much of the use of vapor deposition technology

in the United States is for the preparation of cutting tools and the coating

of wear surfaces. No reliable market projection for the impact of CVD diamond

or cubic boron nitride (cBN) on U.S. industry are presently available; however

the market for diamond and cubic boron nitride tools and wear surfaces in

Japan has been estimated and is expected to grow to approximately 2.7 billion

U.S. dollars by 1995 compared to a 1988 volume of slightly over 600 million

dollars. [1] The 1988 volume was of course almost entirely dependent on high

pressure/high temperature (HPHT) synthetic diamond and cBN powders.

These estimates do not reflect the likely impact of diamond tools on the total

national economy. This is because CVD diamond tools and coatings for high

temperature wear resistance are quintessential enabling technologies. For

example, enormous increases in machining speeds over the last century have

resulted in tremendous increases in manufacturing efficiency. This was made

27
possible due to the development of new cutting tool materials such as tungsten

carbide, silicon nitride, cubic boron nitride, and polycrystalline diamond

compacts. While CVD diamond is postulated to replace polycrystalline diamond

compacts, the greatest impact may well be in tooling and wear applications not

yet anticipated. It is axiomatic that the development of new materials for

manufacturing processes often leads to new processes not previously

anticipated by the original pioneers in the field.

A simple example to illustrate this is the development and introduction in the

early 1970s of fuse-quench zirconia/alumina abrasives which were expected at

the time to serve primarily as improved products for the grinding of low

carbon steels. It was rapidly discovered that with the improved performance

and reliability of these products, computer controlled abrasive machining

operations were possible. This in turn resulted in significant improvements

in the manufacture of lumber with the replacement of steel knives by abrasive

planing machines and the design and construction of computer controlled

abrasive machining units to replace more conventional milling of transmission

cases and engine heads.

A similar, but likely more profound effect can be expected in the present case

of CVD diamond with many new operations becoming feasible. It is this

anticipation that appears to drive much research and development in Japan. In

1987, Dr. Akio Hara of Sumitomo Electric Industries presented data on the

development and performance of high frequency diamond coated speaker

diaphragms for use by the Sony Corporation [2] . In the course of his . i presentation he remarked that the major improvement in audio fidelity afforded

by the diamond coating was well outside the range of human perception so that

"... your dog is likely to appreciate it more than you are." The joke was well received by the audience, but, the point was that Sumitomo judged the

strategic implications of CVD diamond sufficiently important to justify

exploiting any opportunity for developing a quality product in the effort to

develop a high quality manufacturing technology base for CVD diamond based

products. Sumitomo, along with others, has subsequently introduced other ' products, including small end mills for various cutting operations. Whereas

many North American and European tool manufacturers tend to await the

development of an economically viable production scale technology, prior to

the limited introduction or test marketing of new products, at least some Japanese manufacturers appear to view their initial product introductions as important elements in the process/product development program itself. Close

ties between customer and vendor are considered critical to successful

process/product development.

This view of Japanese product/process development is consistent with an overall pattern of traditional Japanese industrial organization or keiretsu,

in which close, almost familial, relationships are maintained between

industrial consumers and suppliers. It is expected that this strategy will

also be pursued in the development and exploitation of CVD diamond technology

for tooling and wear applications.

Initial Products and Production Processes

One of the current problems limiting product design at present is satisfactory

adhesion of CVD diamond to many substrate materials of interest. Numerous

28
strategies are being pursued by different manufactures to overcome this

problem. A major current item of manufacture is the powdered diamond compact

or PDC which is viewed by many as a potential material for the CVD diamond to

replace. This product is produced by a process in which diamond powder, a metal binder or catalyst, and usually some graphite powder are combined, often

with a substrate in place, and sintered together at high pressure with some transformation of the graphite to diamond to produce a high density composite

structure with many of the properties of diamond. There are several

variations of this process with the original work [3] having been accomplished

within a decade after the invention of the HPHT process for diamond

manufacture

.

With the development of a process technology for rapidly depositing relatively

thick layers, CVD diamond products might be more economically manufactured

with some promise of improved performance. Although some crystal-crystal

bonding is obtained in many PDC products, the necessary presence of a binder

phase or the retention of some of the metal catalyst limits their hardness and

performance. It is expected that with the absence of a binder or catalyst

metal at the cutting surface, and coupled with the higher anticipated thermal

conductivity of a pure diamond layer, much superior performance can be

obtained from a CVD diamond surface on the tool.

An approach being pursued by some Japanese companies, notably Asahi Diamond

and Sumitomo Electric, is to grow relatively thick layers of CVD diamond,

where good crystal -crystal bonding is obtained without the need for a binder

phase. The dummy substrate, used only for the growth of the diamond, is then

removed to produce a free standing thick layer. This layer is then machined,

typically with powerful lasers, to the desired shape and bonded to a suitable

tool substrate. The fabrication of a multiplicity of shapes then becomes

possible through laser machining of the free standing "slab" of diamond

without the need for specialized dies and presses for each product shape or

tjrpe. High nucleation densities on the growth substrate ensure that one surface of the free standing diamond layer is smooth and the typically rough

surface on the growth side of the layer would contribute to adhesion to the

tool base.

Critical to success in this approach is the process technology for growing

relatively thick free standing layers of CVD diamond and its brazing to

suitable tool base materials, notably 8 to 12 weight per cent cobalt cemented

tungsten carbide (WC-Co) . Almost all of the pioneering work reported for the

high rate growth of thick diamond layers has come from Japan and in the

interviews conducted as a part of this study, both Sumitomo Electric and Asahi

Diamond exhibited considerable confidence in their ability to use a variety of

techniques to accomplish this. Asahi Diamond reports that they hold or have

exclusive licenses to U.S. patents covering both electron assisted hot

filament CVD methods and superior bonding or brazing technologies. In

addition, many more patent applications are reported to be pending in both the

United States and Japan. It should be noted that with the ability to grow

thick free standing diamond layers economically, and the ability to laser

machine these layers to precise shapes, numerous other products, including

potentially high thermal conductivity substrates for electronic packaging and

various medical devices, become feasible.

29
Ideally, an ultimate objective is to grow diamond directly on the desired tool

support. However, the number of materials on which diamond can be grown with

good adhesion is limited. The tool support of greatest interest is WC-Co

because of its excellent hardness, toughness and strength at relatively high

temperature. Many Japanese companies are aggressively pursuing different

strategies to coat this material with CVD diamond in order to obtain

sufficient adhesion. To date, consistently high adhesion on high cobalt

containing tool bases remains an elusive goal. Consequently, several

organizations have opted to use other tool base materials, while continuing

their investigation of different approaches to coating WC-Co.

Idemitsu Petrochemical Inc. has announced the introduction of diamond coated

silicon nitride based lathe inserts for the machining of high silicon aluminum

alloys in the automotive industry, an important machining problem to this

industry. Samples of these inserts were given to different members of the

study group. Alternatively, Toshiba Tungaloy, Inc. has pursued several

different strategies for enhancing diamond adhesion to WC. The most

successful strategy has been to eliminate the cobalt binder normally used and

make a sintered tool of 100% WC which is then decarburized at the surface.

The carbide is subsequently reformed in the diamond deposition process to give

a very fine grained structure with high diamond nucleation density.

Researchers report that this approach is successful in producing good

adhesion.

Some of the most extensive test data on prototype products has been provided

by Mitsubishi Metal Corporation. It is one of the few organizations reporting

satisfactory adhesion of diamond coatings on WC-Co through the use of

proprietary surface pretreatments . [4]

Several of the manufacturers visited indicated considerable interest and

activity in the synthesis of cBN. The expectation was that the range of

cutting and machining applications might be extended to ferrous metals by

applying a layer of cBN to the diamond at the cutting surface. This would

effectively inhibit the accelerated wear of the cutting edge normally observed

on ferrous metals with an untreated diamond surface. However the study group was repeatedly told by several companies visited that developments with cBN were still too immature to be discussed freely.

CVD coatings for cutting and machine tool applications have evolved from

relatively simple single layer coatings to multiple layer coatings for

different applications as the deposition processes and coating materials have

matured [5] and it is likely that similar evolution will occur in the

development of CVD diamond coatings as the understanding of how to achieve

satisfactory material and process combinations is developed. Among those

developments that one might anticipate coming from Japan in the foreseeable

future are the design of multilayers to control residual coating stresses and

to ensure a broader range of applications and the design of material composite

coatings with CVD diamond as an element in the composite design.

THERMAL MANAGEMENT ,

.

Diamond's superior thermal conductivity makes it very attractive for heat

transport and thermal management applications. While several industrial

30

V
organizations believed this application of CVD diamond would be realized, a few did not. Those pursuing it included Fujitsu, Idemitsu, Asahi Diamond,

Seiko Instruments, and Kobe Steel. Fujitsu is interested in diamond heat

sinks for laser diodes and VLSI supercomputer chips, and has made CVD plates

as large as 3 cm x 3 cm 2 mm. Idemitsu is concentrating on depositing thick

diamond films on silicon nitride substrates due to the excellent match in

thermal expansion up to 1000 °C. Seiko Instruments thinks a technological

barrier to commercializing CVD diamond heat sinks is the inability to deposit

diamond films of sufficiently high quality to have the highest possible

thermal conductivity. They believe heat sink applications are 2 to 3 years

away. Seiko has a highly developed method for measuring thermal conductivity.

It should be noted that to our knowledge only NEC, Seiko, and Asahi diamond

measure thermal conductivity.

Semiconductor Energy Laboratory, while having no activity in heat sinks at the

present time, sees potential for them as heat transport aids for other

semiconducting devices

.

While Kobe Steel is growing diamond films on silicon for heat sink

applications, they anticipate a low probability of successful economic

commercialization of thick CVD diamond films for this application. Sumitomo

Electric did not yet see a CVD process for making thick diamond films for heat

transport that could compete with bulk diamond heat sinks fabricated from

diamond crystals made by the HPHT process.

Finally, the New Diamond Forum predicts the following market size for diamond

heat sinks: 1995 - $150 M; 2000 - $360 M; 2010 - $700 M, assuming 150 yen to

the dollar, the exchange rate during our visit.

ELECTRONIC AND OPTOELECTRONIC DEVICES

The combination of diamond's high band gap, high mobility, high thermal

conductivity, and high carrier saturation velocity makes diamond a likely

candidate for high power, high speed electronics. A number of Japanese

institutions and companies are fabricating electronic devices from

polycrystalline and single crystal diamond films. Sumitomo Electric, Osaka

University, Kobe Steel, and Matsushita Electric are active in device

fabrication research.

The devices are typically test structures such as Schottky diodes, MESFETs,

light emitting devices, and thermistors. Outstanding performance from these

devices has not yet been observed. Sumitomo has fabricated a variety of

devices. Diamond MESFETs have been fabricated from boron doped CVD diamond

deposited on single crystal HPHT diamond substrates. The gate length and

width were 80 /xm and 150 ixm, respectively. Ti was used for ohmic contact to

the source and drain while W was used for the Schottky barrier metal. When 1

fim p-type layers were deposited on the substrates followed by the

metalization, transistor behavior was observed, but the source to drain

currents were extremely small. Improvements in the source to drain current

have been obtained by depositing a 0.90 fxm p-type layer and then a 0.23 fim intrinsic layer before the metalization. The operation of these transistors

at elevated temperatures was not reported.

31
Besides MESFETs, thermistors and light emitting electroluminescent devices

have been fabricated at Sumitomo Electric. The light emitting devices were fabricated from boron doped epitaxial films using W as the Schottky barrier

metal. A whitish emission was observed when 40 to 100 V were applied. The

spectrum of the electroluminesence was similar to the spectrum of

cathodo luminescence observed on this film. Thermistors were fabricated from

boron doped polycrystalline diamond deposited on silicon nitride substrates.

A thermistor device fabricated from CVD diamond doped with boron changed

resistivity by two orders of magnitude with a temperature change from room temperature of 500 °C. The B/C ratio in the feed gas phase was 200 ppm,

Osaka University has fabricated light emitting devices from polycrystalline

films deposited in magneto -microwave plasma and conventional microwave plasma

systems. Some of the equipment was supplied by Semiconductor Energy

Laboratory and by the Shimadzu Corporation. Boron doped films, 1 to 5 ^m

thick, were deposited on p-type Si substrates and then were metalized with Al

,

W, Au, or Pt. Electroluminescence was observed when the forward bias exceeded

25 V or when the reverse bias exceeded 20 V. The electroluminescence spectrum

coincided with the cathodoluminscence spectrum that had been observed from the

specimen. The emission spectrum showed a peak at 2.35 eV with a shoulder at

2.7 eV.

In parallel work at Osaka University, Schottky barrier heights of diamond on various metals are being studied. Researchers have found that treatment of

the CVD diamond surface with a solution of chromate in sulfuric acid produced

consistent Schottky barrier heights with different metals. X-ray

photoemission studies of the acid treated surface revealed a substantial

amount of oxygen, a small amount of sulfur and no detectable chromium. To

determine the effects of oxygen on the Schottky diode formation, diamond

surfaces were exposed to oxygen discharges in the absence of wet chemistry

prior to metallization. The barrier heights were similar to the heights found

on those samples that had received the acid treatment.

A major goal of Kobe Steel's diamond effort is to develop a diamond

electronics technology. The work on diamond devices is still evolving.

Specifically, researchers are targeting polycrystalline diamond as an electronic material. They are actively involved with doping, broad area

deposition, selected area deposition, reactive ion etching, electrical

characterization, and fabrication of simple test structures. No results from

the test structures were reported. It seems likely that, given the level of

effort, diamond devices will be forthcoming soon.

OPTICAL APPLICATIONS: COATINGS, LENSES, WINDOWS AND X-RAY WINDOWS

Introduction

A combination of superior properties make diamond highly desirable as an optical material. Diamond is transparent over wide ranges of wavelengths from

the ultraviolet through the visible and most of the infrared. Great hardness

makes diamond desirable as a protective optical coating that would be useful

on missile domes, aircraft windshields, or supermarket scanners. High thermal

conductivity makes diamond useful in applications requiring rapid dissipation

of heat, such as windows in high power laser systems. High refractive index

32
of diamond makes this a choice material in specialized laser applications such

as resonant stack reflectors used in polarizers. Electronic properties make

diamond and/or doped diamond potentially useful as an ultraviolet detector and

as an electroluminescence emitter.

State-of-the-art CVD diamond may soon be usable as an optical material due to

progress in reducing optical scatter and defect induced absorption. While

other applications of CVD diamond films, such as machine tool and abrasive

applications are tolerant of the presence of impurities and graininess in

polycrystaline films, nearly all optical applications require extreme material

homogeneity, smooth optical surfaces, minimum impurity content, and negligible

optical absorption.

Recent Developments

Progress over the past year on different fronts of CVD diamond film research

is expected to advance new optical applications of diamond films. Significant

progress has been reported in three major areas of the technology, polishing

polycrystalline diamond, depositions over large complex shapes, and high

deposition rates. Polishing of polycrystalline diamond films to average

surface roughness less than 3 nm has been demonstrated by TIT using a newly

developed fast and efficient polishing method. (See Post Deposition

Processing/Chemical Polishing on page 23.) This method could be extended to

polish large surface areas and also non-flat surfaces.

The new hot plasma deposition methods allow for deposition of diamond films over large areas and over complex shapes, such as domes, at deposition rates

two to three orders of magnitude higher than the microwave and hot filament

CVD methods. Unfortunately these methods produce diamond films that are not

yet suitable for most optical applications. The challenge remains to deposit

high optical quality diamond at high deposition rates and at reasonable cost.

Progress also has been made in the deposition of diamond films that show

preferential orientation of the individual grains. The SENTAXY technique for

selected area depositions offers the promise of oriented diamond grain.

In the United States, an important development has been the deposition of

thin, smooth, transparent diamond films over areas greater than two inches in

diameter. The films remain in tension after etching away the central region

of the silicon substrate, leaving a large unsupported diamond membrane. The

great stiffness and large x-ray transparency make these diamond membranes an ideal material for x-ray lithography. The diamond provides the support for

the x-ray mask material which can be etched to the desired pattern by electron

beam lithography. Oiily Seiko Instruments reported an interest in this type of

work

.

A most important breakthrough for optical and electro-optical applications, as it would be for electronic applications, would be development of a method for

heteroepitaxial growth of thin and thick single crystal diamond films.

Optical Applications of Diamond in Japan

Of the many possible applications of diamond films, optical applications

appear to have low priority in Japan. This is probably because the high

33
material quality deemed necessary for optical applications has not yet been

achieved by any of the current film deposition processes. The best film

quality from the point of view of optical applications is achieved by

microwave plasma enhanced CVD methods. Low methane concentrations and the

presence of oxygen in the feed gas are preferred for enhanced optical

transparency. Deposition conditions that promote grain sizes that are small

compared to the optical wavelength of the application, are preferred because

the smaller grains sizes lead to smoother surfaces, thus minimizing the need

for optical polishing. Small grain size is desirable for self supporting

optical membranes and for optical hard coatings. Large grain films, which

usually have the highest thermal conductivity, must be polished before they

are usable at all except the longest infrared and microwave wavelengths.

None of the Japanese organizations visited were observed to have activities in

optical applications. Several of the research groups, however, have been

involved in optical characterization of diamond films. These

characterizations included measurements of optical absorption in different

portions of the electromagnetic spectrum. Of most interest are studies of the

visible and near infrared transmission spectra of films that were deposited by

a variety of methods. Surface and volume scattering measurements were also of

considerable interest to these groups. Progress in optical polishing of

polycrystalline films was tracked by measuring optical surface scatter.

According to researchers at Sumitomo Electric, the market is too poorly

defined for projecting the commercial markets for optical applications of CVD

diamond at this time. Success in deposition of crystal diamond films for

electronic applications is expected to benefit optical applications as well.

Seiko Instruments is currently working on optical applications of diamond and

DLC films. The films are used as scratch resistant protective layers on watch

lenses. The company is also interested in x-ray windows and diamond membranes

for x-ray lithography applications. Researchers optically characterize their

microwave plasma CVD films.

Kobe Steel is not working on optical products directly; however, they are actively involved in improving diamond film quality for electronic

applications. This company also believes that improved diamond film

processing methods will eventually benefit the optical applications areas.

Showa Denko has no specific optical component development efforts at present;

however, they are very much interested in diamond film polishing technology

and its advancements. They were the first company to demonstrate the

deposition of CVD diamond domes, tubes, and other complex shapes.

NEC and Sumitomo Electric are currently conducting synchrotron lithography

research. Neither indicated ongoing work on diamond membrane development

which is considered to be important for x-ray lithography. This area of

research is probably highly proprietary.

Osaka University uses optical characterization of their diamond films to

monitor film quality.

The polishing work being done by Professor Yoshikawa's group at TIT is

probably the most important post deposition processing technology for optical

34
applications. Very low optical scatter from these newly polished surfaces

show exciting evidence that optical applications for diamond films are not far

away

.

REFERENCES

[1] New Diamond 1990, Japan New Diamond Forum, Ohmsha, Ltd., Tokyo, Japan,

1990.

[2] A. Kara, N. Fujimori and S. Yazu, "Research and Development of Diamond

and Diamond-like Carbon Coatings in Sumitomo Electric Industries," Paper

N4.1, 1987 Fall Meeting of the Materials Research Society, Boston, MA, Dec. 2,

1987.

[3] A. Blainey and J . H. Custers, U. S. Patent no., 3,239,321 (1966).

[4] N. Kikuchi and H. Yoshimura, "Diamond Coated Inserts," New Diamond 1988,

Japan New Diamond Forum, Ohmsha, Ltd., Tokyo, Japan, 1988.

[5] D. T. Quinto, J. Vac Sci. Technol., A6 (3), 2149 (1988).

35
MANUFACTURING TECHNOLOGY

Probably because of its proprietary nature, little information was made

available to us on manufacturing technology. For example, regarding specific

equipment development for manufacturing, nothing was revealed. Regarding

scale -up, however, there were a number of views depending on the application.

For electronics, it was generally concluded that the microwave-assisted CVD

process would be used because of its cleanliness and the ability to control

depositions. For large area sources, some would favor the hot filament CVD

because of the ease with which it can be scaled up in size. For thick parts, some favored the DC plasma jet. A summary of product -dependent scale -up

approaches is given in Table 3.

For process controls, nothing unique was described. The controls that were mentioned included only those for flow, pressure, and power. For sensors, the

situation was similar. Sensors mentioned were optical pyrometers for

temperature, and standard gas pressure sensors. Asahi stated that they

measured in situ film thickness but did not say how. NIRIM plans to explore

the use of RHEED to assess film quality. As an indirect sensor application,

the Semiconductor Energy Laboratory used an optical sensor to measure the

hydrogen- alpha line emission in the microwave discharge in order to adjust,

refine, or make a more uniform discharge.

Automation of DLC film deposition has been achieved by NEC. Disks are loaded

from a multiple substrate holder into the reactor by machines. Matsushita has

developed a continuous DLC film Coater.

36
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37
COMMERCIALIZATION

PATENTS AND LICENSING

It is well known that the Japanese patent system differs from the U.S. system.

A Japanese inventor need only to submit a summary of an idea without reducing

the idea to practice. The submission date is the date of the patent.

Every group we visited mentioned their patents on CVD diamond processing. The

only relevant answer to a direct question on patents was given by people at

Kobe Steel and at Showa Denko , who were very matter-of-fact about the answer. They said that if and when they needed to get patent protection they would

seek cross -license agreements with other companies. All governmental,

university and industrial organizations in Japan seek patent positions in

Japan, and also in the United States and in Europe.

PRODUCTS NOW ON THE MARKET OR EXPECTED TO BE ON THE MARKET SOON

Heat sinks

Heat sinks are made of thick diamond films (thickness greater that 50 /im) on

Mo, SiC or silicon substrates. This activity was discussed at Showa Denko

K.K. , Sumitomo Electric, and at Kobe Steel. A particular application is a heat conducting substrate for laser sources to be used for fiber-optic

communications

.

Free-standing Cones, Domes, and Speakers

Loud speaker diaphragms were the first CVD diamond products to reach the

market. These free-standing diamond film parts also have application to

optical domes. These products were discussed at Showa Denko and at Sumitomo.

At Sumitomo, 2 ^m of diamond and 0.5 of SiC are deposited onto an AI2O3

speaker cone. The upper limit of the frequency response of the speaker shifts

from 50 KHz to 100 KHz.

TAB Bonding Tool

Diamond deposited on metal or ceramic substrate is used as a TAB bonding tool.

This tool is used to surface -mount electronic devices. The diamond acts as a heat transport medium that provides a non- wetting surface for solder. This

application was discussed at Sumitomo Electric, Showa Denko, and Kobe Steel.

Cutting Tools »

Diamond is being used as a coating on SiC, WC , and SigN^ tool substrates.

Companies with products on the market or expected to be on the market soon are Idemitsu, Mitsubishi Metal, Toshiba Tungaloy, Sumitomo, Showa Denko and

Semiconductor Energy Laboratory. Sumitomo has a brazed CVD diamond end mill

cutter on the market.

38
Sales of Diamond Deposition Equipment

Semiconductor Energy Laboratory indicated that they would sell their magnetic

field enhanced ECR system. These systems are constructed by Osaka Vacuum and

Seiko Instruments . One of these systems was observed in operation at Osaka

University

.

Another magneto -microwave plasma deposition system was also observed at Osaka

University. This reactor system was built by the Shimadzu Company. Such

systems are available for purchase with a wide variety of optional

accessories

.

X-ray Lithography Masks and X-ray Windows

Seiko Instruments had an interest in x-ray lithographic masks although nothing

was revealed about what they are doing in this area. There were no other

Miscussions about x-ray lithography masks except in discussions between

Sumitomo and one of the members of the team who obtained price quotes for

coatings on silicon substrates for this purpose.

Seiko Instruments manufactures an x-ray window for instrumentation.

39
THE GOVERNMENT ROLE*

The role of the Japanese government in promoting science, technological

infrastructure, and the eventual commercialization of products is generally

complex and multi- faceted. Many national government agencies play roles

including the Ministry of International Trade and Industry (MITI) , The Science

and Technology Agency (STA) and the Ministry of Education, (MOMBUSHO) which

funds research at universities. These national agencies are often

complemented by local government activities which assist in funding and/or

organization, working with individual companies, consortia of industries and

counterpart research programs in universities and government laboratories. No

single pattern characterizes all developments leading to commercialization and

the system is best characterized by its flexibility and adaptability to

circumstances. In the instance of thin film artificial diamond technology,

the story is relatively straight forward and one may readily discern the role

of government agencies and, in particular, the government laboratory, the

National Institute for Research on Inorganic Materials (NIRIM)

,

The national institutes of the STA, and indeed much of Japanese science,

operates on the "Research Group" system. It is instructive to quote NIRIM'

s

printed brochure on the rationale and structure.

"Research Group System

Specialists of various fields form a research group in order to attain a project target. They investigate inorganic compounds which meet

practical requirements, with particular attention to properties,

composition, structures, and synthesis.

The group research period is usually set at five years. At the end of

the period, it is determined whether the research project is to be

terminated or to be extended for an additional specific period of time.

When a research project is completed, the research group is dissolved

and a new research group is organized to undertake a new project."

The concept of a finite number of targeted research objectives is central.

There are about 120 research scientists divided into groups. Typically, each

group has some eight researchers formed around topics such as "diamond,"

"tantalum carbide," "zinc oxide." The facilities are on a par with any

equivalent laboratory in the United States.

Research on thin film synthesized diamond began at NIRIM in 1972 in parallel

with work on high pressure synthesis. These programs have met with success after success, and so, although the specific research agenda has evolved, both

*Based on visits to Science and Technology Agency (Dr. T. Shirao, Director of

Materials Science and Technology, Bureau of Research and Development); Japan

Research and Development Corporation (Dr. M. Goto, Senior Vice President and

former Director General of the National Institute for Research on Inorganic

Materials); and the Ministry of International Trade and Industry (Dr. M.

Sonai, Director, Fine Ceramics Office). A more complete discussion of the

organization of national support for R&D in Japan may be found in Appendix D.

40
thin film and high pressure synthesis continue as part of the current NIRIM

research agenda. By 1977 the NIRIM group began to have significant results

worthy of publication. From 1977 through 1984 their work led to process

patents of three kinds, all based on the chemical vapor deposition of diamond

film using CH^/H2 mixtures: a) hot filament; b) low- frequency ; and c) highfrequency (microwave) . These patents have become the base for a developing

industry in structural applications of diamond. Improvements in the

technology and development of new processes have continued at NIRIM, with

application interest shifting toward the use of diamond as a semiconductor.

Focus has now centered on understanding nucleation, controlling doping and on

the growth of single crystal heteroepitaxial films. They believe that success

in this area could lead to commercial possibilities rivaling those of the more highly touted high- temperature superconductors. More details about the

technical program at NIRIM may be found in Appendix D.

The role of transfer of government developed technology to industry in Japan

is shared by two agencies, the Agency of Industrial Science and Technology

(AIST) of MITI which focusses on MITI -developed patents, and the Japan

Research and Development Corporation (JRDC) , an area of the STA which works

with STA initiated programs, but also acts as manager of government- developed

patents initiated by other agencies.

In 1984, the NIRIM patents on artificial diamond were transferred to JRDC

which developed the business plan designed to stimulate commercialization.

It sought industrial applications and from among these selected two companies

for initial development programs. Exclusive, but limited, licenses were

granted to Mitsubishi Metals for application of patents a) and b) to cutting

tools and to Seiko Electronics for application of patent c) to heat sinks for

semiconductor packaging. These licenses expired in 1990. In addition,

recognizing that further development would be required before

commercialization was possible, JRDC granted these companies zero- interest

,

forgivable loans for the first 3 years of development. If no profit is made

from use of these patents, no return of funds to the government will be

required.

[JRDC has several functions, but in FY 1989 nearly ¥6B (approximately $40M) was allocated for the development of new technology. In that same year,

repayment of loans for development funds and revenues from licensing brought

¥5. IB to JRDC for further dispersal. This is a highly successful program with

a history extending back 28 years.]

Throughout this development period, NIRIM has acted as a technical resource

for Mitsubishi and Seiko as well as for other companies which were stimulated

by NIRIM' s success (and in several cases frustrated by their failure to be

chosen by JRDC) and initiated their own R&D efforts on CVD diamond. The

Visiting Research Officer program at NIRIM was effective in this regard.

Scientists from industries, paid for by industry, spend time at NIRIM working

with the government scientists and carrying back NIRIM technology to their

companies. (This is similar to the Industrial Research Associates program

which operates at the NIST in the United States.)

It is somewhat surprising to find that in this sequence of events leading to

commercialization, no significant role was played by MITI, the Ministry of

41
International Trade and Industry. In fact, MITI's role as usual, was arrived

at by consultation with industry. It appears that the efforts by the JRDC

followed so quickly by strong competitive pressures from many companies left

no significant role to be played by MITI and that agency was advised by its

industrial consultants to concentrate its efforts on other priorities. In

fact, the only role played by MITI has been their minimal funding in

assistance of The New Diamond Forum, a trade association with membership

including about one hundred producers and potential users of artificial

diamond (both CVD and high pressure). The MITI funding of about ¥5 M/yr.

(approximately $32 K/yr.), used primarily to defray publication costs, will

cease in 1992 and the association will be on its own.

In recent years, JRDC has extended further limited licenses to other companies

including Shingitsu Chemical Industries [patent c) for surgical knives - they

are already paying royalties] Yamaha [patents a), b) , and c)] for high

fidelity speaker cones, and Sumitomo Electric [patent c) for cutting tools].

At the same time, other companies have developed their own processes and are moving towards commercialization.

In these structural applications areas, intense competition is now setting in

with each company producing or readying itself for production of specific

marketable products. The government role was to carry out basic research and

then, as appropriate, stimulate commercialization through licensing,

technology transfer, and forgivable loans. This successful process is used

over and over in Japan in other technologies as part of the Japanese success

story.

42
APPENDIX A

Planning and Implementation of the Assessment

The initiative for this assessment was taken by the Office of International

Affairs in conjunction with the Materials Science and Engineering Laboratory

of NIST, in response to requests for such activities from various committees

overseeing the United States -Japan Agreement on Cooperation in Research and

Development in Science and Technology.

The decision to conduct this assessment was made in January, 1990. It became

necessary to compose a calendar of actions required for implementing the

assessment. The key phases of the assessment were: selecting the members of

the delegation; composing the agenda for the assessment including sites to be

visited in Japan; conducting the assessment by visiting Japan; and presenting

the results of the assessment.

The visiting delegation was selected from government, universities, and

industry. All members received letters of appointment from D. Allan Bromley,

Director of the Office of Science and Technology Policy.

The government delegates were from NIST, which was leading the delegation, and

from the Naval Research Laboratory, which has the largest in-house

governmental program in CVD diamond research. The university delegates were

all widely recognized pioneer researchers in the field.

In order to promote the greatest openness from our Japanese hosts, we chose

delegation members from companies that would be users of CVD diamond products; we did not choose members from companies that were potential competitors in

diamond production.

An agenda for the visit was set at a planning workshop held at NIST on March

27, 1990. In addition to attendance by the delegates, people from government

and industry with an interest in diamond technology were also invited. At

this workshop, a questionnaire that provided the basis for the questions asked

during our site visits was composed. Finally, a preliminary outline of this

report was prepared. Team members were assigned the responsibility for

writing subsections of the report. For each of the two major sections of the

report, a cordinator was chosen to assemble the material provided by the

writers of the subsections.

By fortunate coincidence. Dr. Takayuki Shirao of the Science and Technology

Agency in Japan had been visiting NIST during the early planning stages of our assessment. He offered to assist us in arranging our itinerary and this

assistance proved to be invaluable in assuring the success of our visit. On

the basis of frequent communications by FAX with Dr. Shirao, we devised the

itinerary for the visit.

The sites to be visited in Japan were selected on the basis of recommendations

from the delegation members. In order to visit all of the sites, the

delegation was divided into several teams so that several site visits were conducted in parallel. Although every member of the team could not visit

every site, we were able to visit many more sites. One team member was assigned to prepare a site report for each place visited. The site reports,

43
which appear in Appendix B, provided the information needed for preparing the

main part of the report.

The visit took place between May 28 and June 5, 1990. At the conclusion of

the visit, a meeting was held at the American Consulate in Osaka where we wrote our preliminary conclusions and recommendations and where we refined the

outline of our report.

The prelimary results of our assessment were presented to government and

industry representatives at a seminar held September 13, 1990 in Crystal City,

Virginia. This Seminar was organized by the National Technical Information

Service. In this report we present the results of our assessment.

44
APPENDIX B

Brief Assessment of the New Diamond Technology in Europe and in

Other Countries

Significant research efforts in CVD diamond are underway in countries other

than the United States and Japan, The recent initiation of an annual Diamond

Films conference in Europe is a reflection of the great increase in interest

in the new diamond technologies in other parts of the world. A very brief

review of these efforts is given in this appendix.

Some of the most significant findings in CVD diamond research have been

achieved in the Soviet Union, most notably by members of the research team at

the Physical Chemistry Institute in Moscow. This research group was initially

under the direction of Dr. Boris Deryagin. Contributors to this effort

include, among others. Dr. Boris Spitsyn, Dr. A. Fedoseev and Dr. Valentin

Varnin. Both crystalline diamond and diamondlike materials are being

investigated. Apparently, the crystalline diamond work is primarily

associated with Dr. Spitsyn and the diamondlike research with Dr. Fedoseev and

his co-workers. Little is known about the scope and scale of this research

effort, although the recent surge of interest in the United States and Japan

have led to greater efforts in the Soviet Union as well. Details of reactor

types and methods of deposition have not yet been revealed in the open

technical literature.

Another significant diamond effort in the Soviet Union is centered at the

Institute for Hard Materials in Kiev, under the direction of Dr. N.V. Novikov.

The group in Kiev has a long history in high pressure diamond synthesis and is

now expanding its efforts into low pressure CVD as well. Again, the scope and

scale of this effort are not available.

In western Europe, a major center of CVD diamond research appears to be that

of Dr. Benno Lux at the Technical University of Vienna. Dr. Lux has been

actively pursuing low pressure diamond growth since the early 1980s. His

efforts are concentrated heavily in the production of diamond coated tool

inserts. Very fundamental and important studies of nucleation and growth

processes during diamond CVD have also been undertaken by this group. This is a major and significant research program.

Another major center of research in Europe is at the Fraunhofer Institute in

Freiburg, under the direction of Dr. Peter Koidl. This group has been working

on diamond- like films since the early 1980s and has more recently switched its

attention to crystalline diamond as well. Other important centers of diamond

research in Germany include: the Institute for Plasma Physics at Julich, the

University of Frankfurt, the Institute for Physical Chemistry at Heidelberg,

the Institute for Nuclear Physics at Karlsruhe, Phillips Laboratories, and the

University of Hamburg among others.

In France, significant research papers have appeared from several institutions

including the Paul Pascal Research Center, The University of Nantes, and at

Grenoble. Theoretical studies of diamond- like hydrocarbons have been reported

by J.L. Bredas, University of Notre Dame, Namur.

45
There has been a very long and distinguished tradition of diamond research in

Great Britain. An annual "Diamond Conference" supported by DeBeers is a focal

point of these research efforts. There has been a concentration of effort on

the detailed study of defects in natural diamonds and the friction and wear

characteristics of diamond surfaces. Leading figures in these efforts

include, but are not limited to: Sir Charles Frank and Sir Andrew Lang at

Bristol University; Dr. Moreton Moore at the Royal Holloway and Bedford New

College; Judith Milledge and Monica Mendelssohn of the University College,

London; Dr. Dennis Tabor of the University of Cambridge; Dr. R. Berman, Dr.

Eileen Wilks and Dr. John Wilks of Oxford University; Dr. Robert Jones of the

University of Exeter. In the last several years, interest in low pressure

diamond growth has been evident among British workers. However, it appears

that much of this research is supported by DeBeers and the results and methods

are inaccessible at the present time.

One of the major research centers in Britain has been under the direction of

Dr. A.H. Lettington at the Royal Signals and Radar Establishment, Malvern.

His work has primarily concentrated on diamond- like films as protective

coatings for infrared optics. Important theoretical studies of diamond- like

materials have been conducted by Dr. John Robertson of the Central Electricity

Research Laboratories and E.P. O'Reilly of Surrey University. In addition, a consortium of several university groups has been assembled in the United

Kingdom to work on carbon films.

A very significant research and development capability exists at the Drukker

Diamond Corporation in the Netherlands. Dr. Michael Seal has been the leading

research figure in this company for many years. He has, however, very

recently retired from his position as Director of Research. Drukker has

maintained close affiliations with universities in the Netherlands, e.g.,

University of Nijmegen, and researchers from this group have recently

published papers on diamond CVD. The Drukker company has perhaps the most

broadly based experience with the high tech uses of diamond of any company in

the world. Their U.S. representatives are the Dubbledee Harris Diamond

Company in New Jersey.

The ASEA Corporation in Sweden has had a long standing history of high

pressure diamond synthesis. In fact, its synthesis of diamond at high

pressures predated that of General Electric. Some CVD diamond work is being

done currently at Uppsala University.

Both high pressure and low pressure synthesis of diamond has been studied for some time in Poland at the Warsaw Technical University, the Institute of

Electronic Materials Technology in Warsaw and at the Lodz Technical

University. Significant studies of hard carbon films was carried out for many

years by Dr. Christian Weissmantel in the German Democratic Republic. How

much the recent death of Dr. Weissmantel will influence this effort is not

known. J. P. Hirvonen, A. Antilla, and J. Koskinen at the University of

Helsinki have reported extensive studies on diamondlike carbons.

Theoretical studies of the thermochemistry of CVD diamond and DLC film growth

is carried out by Dr. P. Deak, Dr. I. Biczo and others under the direction of

Professor J. Giber, head of the Department of Atomic Physics at the Technical

University of Budapest Hungary.

46
The Republic of South Africa has an obvious interest in diamond, both natural

and synthetic. The DeBeers company has entered the CVD diamond field much

later than the leading diamond producers in Japan and the United States.

Nevertheless, their sophisticated and wide ranging capabilities in diamond

research will certainly make them a significant factor in low pressure diamond

growth in the future. Research is now being conducted at the University of

the Witwatersrand, under the direction of Professor Friedel Sellschop and by

Dr. J.F. Prins . Dr. Robert Caveney, Director of Research at DeBeers, has done

work in low pressure diamond growth in the 1970s.

In Australia there are important efforts in diamondlike carbon underway at the

University of Sidney under the direction of David McKenzie and at CSIRO under

P.J. Martin.

47
APPENDIX C

Site visit Reports

AOYAMA GAKUIN UNIVERSITY

Date of visit: May 30, 1990

Visiting Delegation: J. J. Cuomo, J. T. Glass, L. H. Schwartz, and C. M.

Stickley •

The visit was hosted by Professor Tadao Inuzuka. Also present were three

researchers from Toshiba Corporation, Dr. Atsuhito Sawabe , Dr. Hisakazu Izuka,

and Dr. Shinj i Aral,

Professor Inuzuka indicated that he started his work on CVD diamond in 1981

with Dr. Atsuhito Sawabe as a student. They used methane because they

believed its tetrahedral coordination was important. First they produced

amorphous carbon and then diamond. Together they developed the electron

assisted CVD method (EACVD) which consists of a hot filament CVD system with a voltage applied between the filament and the substrate. They found the film

surface morphology was smoother when a voltage was applied than when no voltage was applied. The current was several mA over a 15 mm^ area. Substrates used were Si, SiC, Mo, and garnet. The deposition rate is several

/xm/hr. Nuclei are used to initiate growth. At 0.5% methane the diamond Raman

line is observed with little background signal; however, at 2% methane the

diamond Raman line is observed in the presence of a large background signal.

Nucleation of diamond has also been observed without surface scratching.

Deposition conditions for the EACVD process were: applied voltage, 600-800 V;

electrical current, 400-600 ma; current density, 4-5 a/cra^ ; substrate

temperature, 800 to 1000 °C; CH^/H2, 0.5%, 1%, 2%, 3%, 5%; total gas pressure,

180 Torr; gas flow rate, 300 seem.

Depositions employing evaporation of carbon and atomic carbon beams were

described. Graphite was deposited. It was stated that the monomer C^ , the

dimmer C2 and the trimmer C3 concentrations change according to the

evaporation conditions of the melt. By choosing the evaporation conditions so that Cj^ predominated, an atomic beam is produced and when hydrogen is

introduced into the chamber at a pressure of 10"^ Torr, particles of diamond

were found. SiC was present during this process.

The adhesion of diamond films to silicon substrates was measured. In a pull

test, fracture took place at the diamond/silicon interface. An adhesion force

per unit area of 27 kg/mm^ was measured on one film. We were shown

unpublished data that displayed an effect of substrate thickness on adhesion.

Epitaxial growth of diamond on CaF2 and AI2O3 in a hydrogen plasma were tried

without success. Epitaxial diamond was successfully grown on single crystal

cBN. Small cBN substrates were prepared by a high pressure process similar to

the process for HPHT synthesis of diamond. The diamond begins to grow as particles, similar to what is observed in conventional CVD of polycrystalline

diamond. However, all of the crystallites are similarly oriented so when the

particles merge into a film at a thickness of between 0.2 and 1 yam, the

48
resultant film shows an epitaxial relationship with the substrate. Epitaxial

growth occured on the {111}, (100) and (221) faces of cBN.

ASAHI DIAMOND INDUSTRIAL COMPANY, LTD.

Date of visit: May 29, 1990

Visiting delegation: A. Feldman, R. A. Rudder, M. A. Tamor and W. A.

Yarbrough

.

The visit to Asahi Diamond took place at the company headquarters in Tokyo.

Discussion were held with Dr. Kazuo 0-oka, Director and General Manager of the

Research and Development Division, Y. Yamauchi , Director and General Manager

of the Foreign Trade Department, and Kinichi Goya, Director and General

Manager of Marketing and Engineering. Because of the proprietary nature of

the work at Asahi Diamond, we were not able to see any facilities or talk

directly to research staff. However, we were able to learn about the

philosophy of the company and its view regarding diamond technology.

Asahi diamond was established in 1937 and is a manufacturer of diamond and

superabrasive tools and related precision equipment. However, they have not

been a producer of diamond. As a gage of the size of the company, net sales

in 1989 were 34.8 billion yen or $232 million (at 150 yen per $) . They

believe that marketing controls the stream of technology flow.

Because of its strong interest in diamond tools, Asahi diamond has been

working on CVD diamond for over 5 years. It has started to introduce

prototype products of CVD diamond. We were told that all of the work is

internally funded with no assistance from the Japanese government. There has

been collaboration with Professor Inuzuka of Aoyama Gakuin University who

developed the electron assisted CVD process for producing diamond.

The company holds 20 patents related to diamond with two patents in the United

States, electron assisted CVD, developed by Professor Inuzuka, and a method of

brazing diamond for cutting tools.

Asahi diamond has had a long term commercial relationship with General

Electric (GE) . GE has been supplying diamond to Asahi Diamond for over 30

years. This long relationship has resulted in a cooperative agreement between

GE and Asahi to form a jointly controlled company called Gena systems. The

company is expected to come out with a major product within several months,

and this accounts for the reluctance of Asahi Diamond to reveal any

information regarding the methods they are using to produce diamond and the

nature of the products they are working on. Initially, production of the

product will be done both at Asahi Diamond in Japan and at GE in the United

States; however, production with be done eventually at Gena systems in the

United States.

Listed below are the views of Asahi Diamond on several topics related to CVD

diamond:

Deposition: In their estimation, microwave deposition offers the best control

of deposition and has the greatest possibility for process control. They are investigating the use of hot plasma torch deposition for making thick films

49
which are then attached to the substrate by brazing. They believe CVD is not

a practical method for producing diamond powders at present. However, in

several years the method may prove to be competitive with the high-pressurehigh- temperature diamond. They are not interested in producing diamond

powders by CVD. They are studying low temperature deposition processes and

coatings for sliding surfaces. The company has interest in diamond-like

carbon, and this activity is part of the agreement with GE.

Characterization: They have a large effort in characterization. These

include measurements of nucleation density (they have achieved 10^^/cm^),

hardness (8000-10000 Vickers), thermal conductivity (600- 800w/m) , in-situ

thickness monitoring, adhesion, analysis of hydrogen content, and Raman

spectroscopy.

Semiconducting diamond: Semiconductor use of diamond is a long way off.

Doping is presently being done, however n-type doping is a problem. Another

problem is heteroepitaxial growth.

Diamond quality: A major emphasis of their work on diamond is diamond quality

rather than growth rate and size of deposition area. This implies that growth

rate and size of deposition area are not impediments for them at this time.

Nature of Research at Asahi Diamond: Asahi diamond has 10 people working on CVD diamond. They have excellent scientists. The work at Asahi Diamond is

principally in applications. It takes 6-7 years to convert basic research to an application. They are working on cBN but could not discuss this work with

us

.

Relative position of United States and Japan in diamond technology: Japan is

ahead in applications while the United States and Japan are about equal in

basic research. Japan is believed to spend about 4 times the amount spent in

the United States. However, this number is highly speculative.

The Future: Asahi Diamond considers itself a world leader in CVD diamond.

Its short term interest is in brazed tools of CVD diamond. In the long terra,

it is interested in all aspects of diamond technology. The company believes

in a good future for CVD diamond.

50
FUJITSU LABORATORIES, LTD.

Date of visit: May 29, 1990

Visiting delegation: J. C. Angus, S. Holly, J. W. Mitchell, and K. A. Snail

The visit was hosted by Takahiko Misugi, Managing Director of Fujitsu

Laboratories and Dr. Motonobu Kawarada, Senior Researcher in the Electronics

Packaging Laboratory, Fujitsu Laboratories.

Fujitsu is interested in using CVD diamond as a heat tranport material for . laser diodes and VLSI supercomputer chips. The use of diamond as a tool

coating is also of interest. They are also interested in active diamond

electronics for the future.

Using a DC Plasma Jet, Fujitsu was the first to demonstrate very high diamond

growth rates (greater than 200 /zm/hr) . They have synthesized large plates

(1 X 1 cm X 2 mm thick) of CVD diamond and have built prototype laser diode

assembles on these plates. The plates were fabricated by scanning the

substrate below the plasma jet during the deposition. We were shown one DC

plasma jet in operation in a clean room and were told that two others were located in a separate lab. ,

Currently they are using NMR to characterize the composition of their

deposits. We didn't see how they were measuring thermal conductivity, and

they seemed surprised to hear about the thermal conductivity results reported

by the General Motors research laboratory.

They have also duplicated the polishing apparatus developed by Professor

Yoshikawa at TIT and have begun experiments in polishing diamond, although

most of their polishing has been done with a skeif , a diamond cutters

polishing wheel.

A major accomplishment during the last year was the development of methods for

improving the adhesion of CVD diamond to substrates, presumably for tools.

IDEMITSU PETROCHEMICAL COMPANY, LTD.

Date of visit: May 30, 1990

Visiting delegation: J. C. Angus, S. Holly, J. W. Mitchell, and K. A. Snail

The visit was hosted by Mr. K. Ito, Manager of Planning of High Tech

Materials, Planning and Development Department and Dr. Nariyuki Hayashi,

Diamond Project Leader, Planning and Development Department. The visit took

place at the corporate headquarters so that no laboratory facilities were

seen.

Now one of the world's leading oil companies, Idemitsu Petrochemical

began business in 1911 as a petroleum retailer. The company expanded

substantially in 1957 by acquisition of its first oil refinery in Tokuyama.

Since then, Idemitsu has continued to grow and has become one of Japan's

leading industrial groups. Last year gross sales reached almost 3 trillion

51
yen ($20 billion) . The Idemitsu group of companies now include many domestic

(in Japan) and overseas companies.

The Idemitsu Research Group is a group of research establishments with strong

emphasis on the fields of energy, biotechnology, electronics and new

materials. Research and development work on diamond and related materials are conducted at the New Materials Department at its Research Laboratories in

Chiba. Seven researchers are currently employed in CVD diamond film research

and development work. These researchers are supported by 9 technicians and up

to 5 people at a university. There are approximately 1000 people at the

Research Laboratories in Chiba.

Idemitsu was one of the first companies in Japan to start research in CVD

diamond film technology (1982). Initial work at Idemitsu followed the lead

provided by NIRIM in Tsukuba. The microwave plasma deposition technique

including details of hardware design was borrowed from NIRIM and is still in use today.

Idemitsu considers the use of carbon monoxide instead of methane as a their

major contribution to CVD diamond film technology. Subsequently, they have

secured a strong patent position on the use of CO gas. Carbon monoxide has

the advantage of being usable at much higher percentages (up to 50% and

higher) in the feed gas without interfering with the deposited diamond film

quality. With increased CO percentage the film growth rate increases; thus,

diamond film growth rates in a microwave reactor can be up to 10 times higher

than growth rates based on methane. Growth rates up to 4 /x/hr have been

achieved.

Idemitsu has chosen to deposit diamond on silicon nitride substrates

because of the good thermal expansion match over a large temperature range

(from room temperature to 1000 °C). That may explain, why they have not spent

much effort on developing techniques to deposit diamond film at reduced

substrate temperatures.

Areas of current research interests include:

1. Nucleation and growth studies, gas phase chemistry (calculations by

Professor Nishimoto and his associates at Osaka City University) and doping

studies for potential semiconductor applications. The delegation was shown

the results of electrical conductivity vs. temperature (300 to 650 K)

measurements on boron doped diamond films at different dopant levels.

2. Development of a deposition reactor for coating large areas. The target is

deposition of CVD diamond films on substrates up to 25 cm diameter by 1992.

The two most challenging goals to be achieved over these large areas are the

deposition of films with uniform characteristics and maintainance of high

growth rates recently demonstrated on 1.25 cm square substrates. It is hoped

that sophisticated electronic monitoring techniques will help overcome these

difficulties

.

3. Development of technologies for producing diamond coated tool bits. This

includes studies of cutting, bonding, polishing, and interface layer

development. Idemitsu understands the importance of cBN to the development of

cutting tools for machining ferrous materials , which accounts for an estimated

52
80% of all machining done, and recognizes its importance to their future

business. They did not discuss their work on cBN; however, progress is being

made on this material.

Idemitsu has no HPHT diamond synthesis capability. They showed samples of

dieimond films deposited on silicon nitride. The substrates were polished 12mm

X 12mm X 2mm silicon nitride coated with uniform diamond films approximately

10 fim thick. .

KOBE STEEL, LTD.

Date of visit: June 5, 1990

Visiting delegation: Visited by all members of the U.S. Delegation

Researchers in Kobe Steel's Electronics Research Laboratory, Materials

Research Center, and Mechanical Engineering Laboratory are currently working

on diamond produced from the vapor phase. Major goals are electronic devices

and tool coatings. The total effort consists of approximately five

researchers, but is expected to expand by one or two in the near future.

Presently, 80% of their effort is on understanding and relatively fundamental

research with 20% on applications, but this latter percentage is increasing.

Their electronics oriented research has involved a surface morphology and

micros tructural investigation, oxygen addition to improve film quality, large

area (5 to 10 cm) deposition, p-type B doping and n-type Si doping (although

not clear n-type), electrical properties and contacts measurements, reactive

ion etching, selected area deposition, and fabrication of simple device

structures. Although there was some interest expressed in optoelectronic

devices, current emphasis appears to be on the fabrication of Hall devices,

thermistors, and MESFETs. The electrical characteristics of these devices

have not yet been measured. The substrate material of interest is Si and no homoepitaxial research is underway. Thus, all of the aforementioned devices

are made in polycrystalline diamond films.

The deposition techniques of interest for the electronics area are EACVD and

microwave plasma CVD (both NIRIM type and large area type reactors) . Growth

rates are up to 3 /xm/hr, but need to be improved for applications such as heat

sinks. They are concentrating on microwave plasma CVD due to its scalability

and cleanliness. The NIRIM type reactor developed at Kobe Steel has three

systems connected together to allow p-type, n-type, and undoped material to be

grown without cross contamination, as well as multilayer depositions without

exposure to atmosphere. The large area deposition systems involve a high

power microwave source (5 KW) split into two waveguides connected to a single

chamber. This system is expected to give higher growth rates than the NIRIM

type system they are now using.

Etching has been accomplished in a specially designed D.C. plasma discharge in

oxygen and helium gas mixture, utilizing "focused parallel plate" electrodes.

Etch rates between 1 and 2 /um/hr have been achieved.

When depositing doped layers on undoped layers of diamond, they have

avoided secondary nucleation by introducing H2 into the chamber prior the

deposition and then slowly increasing the methane content in the feed gas.

53
In their study of boron doping, they have examined numerous doping levels by

measuring Hall mobility and current-voltage characteristics. They expressed

no interest in lowering deposition temperatures, but are trying to obtain

smoother surfaces for the fabrication of devices.

A prototype MESFET device is expected within one year, however, this device is

not expected to perform well. As a first generation device, it will provide a baseline for further developments.

Although there is some work on thick diamond films for heat sink applications,

Kobe Steel researchers are discouraged by the low probability of economical

commercialization and are much more interested in thin film applications such

as active electronic devices.

Kobe Steel's effort in tool coatings and other non-electronic applications

involve microwave plasma CVD and combustion growth. They are interested in

enlarging the deposition area and want to understand gas flow and reaction

chemistry in their combustion growth research. There did not appear to be any

specific applications in mind for this study. Tool bits utilized in drilling

printed circuit boards (WC-Co inserts) were coated with diamond via microwave

plasma CVD. Films were prepared by depositing an intermediate buffer layer

between the insert and the diamond. Surface morphology and interfacial

structures have been evaluated but practical testing of the bits has not yet

been accomplished. It is believed that the adhesive bond is inadequate at the

present time and they do not know when they will supply such tools to

potential customers.

Kobe Steel is also interested in cBN coatings and has deposited seemingly high

quality polycrystalline cBN on Si by means of a reactive ion plating

technique. However, it has not been possible to deposit the same films on nonsilicon substrates.

Kobe Steel's diamond effort began in 1985 via interaction with the National

Institute for Research in Inorganic Materials (i.e., a Kobe Steel researcher

spent several months at NIRIM) . Since that time they have been studying

diamond for electronics whereas tool coatings have only been under

investigation for approximately 1 year. They have applied for several patents

but have not licensed the basic technology from NIRIM or others yet. However,

they feel that when a clear product path and the required processing

techniques are determined, it will not be a problem to cross license the " necessary technology. They have not completed a thorough market study for

diamond because they believe that markets will develop as the material and

processing techniques improve.

Amost all of the funding for Kobe Steel's diamond research is internal,

however, a small fraction is derived from a MITI/NEDO joint international

research grant. This project is a collaboration between Kobe Steel, Harwell

Laboratories (England) and North Carolina State University. It involves

research and development of electronic devices in polycrystalline diamond and

results will be published in the open literature. The level of effort is

approximately one researcher at each institution.

Kobe Steel has a major company wide goal of globalization. As such, they have

recently established research laboratories on the East and West coasts of the

54
United States and in England. Combined with their laboratories in Japan, they

refer to this expansion project as "24 hour research" because there will be

Kobe Steel laboratories conducting R&D "around the clock" somewhere in the

world. A laboratory recently established in the Research Triangle Park (the

Electronic Materials Center) will concentrate on diamond thin films for

electronics. This laboratory will serve to increase Kobe Steel's

collaboration with U.S. companies and universities. An ongoing relationship

with North Carolina State University is one reason for the choice of location

of this laboratory. They have also established ties with some U.S. companies

by supplying films deposited in their Japanese laboratories and are seeking

more opportunities of this kind. ;- • •

Finally, diamond is viewed as part of a broader context at Kobe Steel. The

company is currently diversifying from its traditional metal products and

heavy machinery into "high tech" materials. One area that has been targeted

is electronic materials; thus, a background base in electronics needs to be

developed. Diamond is serving as one vehicle for building up this expertise

in electronics. From this standpoint, the sizes of current markets for

diamond are not critical at the present time.

MATSUSHITA ELECTRIC CORPORATION

Date of visit: June 5, 1990 ^ Visiting delegation: J. C. Angus, J. J. Cuomo, M. A. Tamor

Matsushita has a long history of research in the area of diamondlike carbon

(DLC) , and recently started work on CVD diamond for electronic applications.

This work is in part stated interest in deposition of high temperature

materials by "energetic atom" processes. The company is interested in

diamond, DLC, SiC, B^C, and cBN. Their diamond and DLC group is comprised of

eight scientists, five at the Central Research Laboratory, and three at the

Device Laboratory. Discussions were quite open and collegial.

DLC work at Matsushita began in 1976 with deposition of hard films in an RF

diode sputtering reactor. These films were found to be hydrogenated by water

vapor, and no film was formed when the experiments were repeated in an ultrahigh vacuum system. In 1985, this reactor was modified to include a proton

beam for direct hydrogenation. Hard films with scattered microcrystallites

believed to be diamond were formed. This work is similar to work reported by

Weissmantel and others.

A very impressive accomplishment is the development of a high rate reactor for

deposition of hydrogenated DLC onto a 15 cm wide magnetic tape in a reel-toreel web-coating apparatus. The reactor uses RF induction to excite a plasma

of CH4 and Ar in a 50/50 ratio (100 m Torr pressure) and includes an anode to

provide a bias voltage of 700 to 2000 V with respect to the substrate. DLC

with a density of 1.8 g/cxs? , hardness of 2800 kg/mm^ , and less than 5%

hydrogen content (by an unnormalized SIMS analysis) is deposited at deposition

rate of 0.3 ^um/min. For a desired film thickness of 10 nm, the tape speed is

quite high. The DLC coating is protective against both wear and oxidation of an metal thin film magnetic layer and provides dramatic reductions in tape and

tape -head wear. The economics of the process are under evaluation.

55
Diamond work at Matsushita Electric is aimed entirely at development of single

crystal films and contact metallizations for electronics. Both hot filament

and biased microwave plasma reactors are in use. In diamond CVD, the effort

has been to develop new nucleation techniques to promote heteroepitaxial

growth on silicon. One novel experiment has been to use low energy ion

implantation followed by annealing to produce a very thin SiC layer on a Si

[111] surface. Diamond was then grown on this surface without the usual

scratch pretreatment . Along with a few scattered diamond crystallites, a smooth layer with scattered triangular pits appeared. The company expressed

confidence that diamond film is epitaxial, but it must be determined if the

triangular indentations are simply etch pits in the carbide layer. Whatever

the final result, this type of experiment demonstrates a willingness to try

new ideas

.

Researchers at Matsushita felt that although Japan leads in tool applications

of CVD diamond, the United States enjoys a significant lead in basic research

and in some electronic applications. They were keen to exchange ideas, and even entertained the possibility of collaboration in the area of

heteroepitaxy

.

MITSUBISHI METAL CORPORATION

Date of visit: May 30, 1990

Visiting delegation: A. Feldman, R, A. Rudder, M. A, Tamer, and W. A.

Yarbrough

The team met with personnel from the Mitsubishi Metal Corportion to discuss

diamond technology. Mitsubishi Metal manufactures cemented carbide tools and

other products for the machine tool industry. Mitsubishi Metal Corporation

will officially merge with the Mitsubishi Mining and Cement Corporation in

December 1990. Mitsubishi Electric Company remains an independent company and

there is no joint research or other collaboration between Mitsubishi Electric

and Mitsubishi Metal. Mitsubishi Mining and Cement currently does not have a CVD diamond program, but it can be expected to do such product development as might be decided upon using resources available to it through its merger with

Mitsubishi Metals.

Mitsubishi Metal began work on hard carbon coatings approximately 12 years ago

and, with the successful synthesis of diamond at NIRIM, shifted to the study

of diamond in preference to DLC . Mitsubishi Metal has work in CVD diamond

technology not only because of its potential impact on many of its existing

products and business, but also because of activity and interest in electronic

materials. Mitsubishi is also interested in the vapor phase synthesis of cBN,

but no activity was discussed and this field was perceived as not nearly as well developed at the company as CVD diamond.

Diamond deposition equipment was not shown to the visiting delegation because

of its proprietary nature. Extensive characterization and clean room

facilities are available and considerable characterization data on CVD diamond

produced by the company was shared with us

.

The synthetic methods used to produce CVD diamond include both plasma and hot

filament deposition; however, Mitsubishi Metal held exclusive licenses from

56
JRDC to develop hot filament and plasma deposited CVD diamond for cutting tool

applications. These expired in the summer of 1990 and will not be renewed.

The company at present manufactures approximately 5,000 cutting tool inserts

per month for domestic consumption and cooperating in a test marketing program

with selected Japanese customers (presumably automobile manufacturers) . The

deposition method of choice is believed to be a RF plasma technique, possibly

with a DC bias. The R&D team at the company consists of 8 to 10 people, five

of whom are research scientists, and it appears that with the establishment of

pilot scale production, additional personnel are likely to be involved with

production, process engineering, and quality assurance functions.

The tools are prepared by the direct coating of diamond onto specially

prepared cemented carbide inserts, and the company reports that adhesion

difficulties have been sufficiently resolved to permit the use of diamond

coated tools for the face milling of high silicon aluminum alloy engine heads.

The solution to the adhesion problem includes the use of less cobalt and

improved surface treatments ; much of this work has been discussed and reported

in both the United States and Japan. Delegation members were given an English

language copy of Mr. Kikuchi's paper in the publication New Diamond 1990, the

most recent of the annual English language publications of the Japan New

Diamond Forum.

Work at Mitsubishi Metal is internally funded, with evidence of major

management commitment to the development of the technology and its application

to numerous existing and potential products. Government involvement is

significantly less now than in the inceptual stages; however, close

communications and some collaboration with Universities and Government

laboratories (e.g.. Prof. Yoshida of Tokyo University and NIRIM) continues.

The perception of Mitsubishi Metal management is that although researchers in

the U. S. and Japan are approximately even with each other in the scientific

work, technological development, particularly the preparation of prototype

products and processes, is more advanced in Japan than in the United States.

The leader in Japan is believed to be Sumitomo Electric Industries and in the

United States, General Electric. The question was raised as to when

Mitsubishi Metal would be willing to supply U.S. auto manufacturers with test

samples for testing and qualification. No direct response was received but

an interest in the North American market was apparent. The delegation's

impression was that a wider field test and qualification program would come after a substantially more cost effective production technology had been

developed.

NATIONAL INSTITUTE FOR RESEARCH IN INORGANIC MATERIALS

Date of visit: May 30, 1990

Visited by all members of the U.S. Delegation

Background.

The major developments that catalyzed the world wide pursuit of a practical

low pressure diamond technology were made at NIRIM. These were the invention

of hot filament and the microwave plasma reactors for CVD of diamond.

57
The full U.S. delegation visited the National Institute for Research in

Inorganic Materials (NIRIM) on May 31, 1990. After arriving at the nearbytrain station, we were met by Dr. Kamo who escorted us to the NIRIM site at

Tsukuba. NIRIM, one of six government institutes, was established in 1966 and

funded by the Science and Technology Agency (STA) . NIRIM' s annual budget is

$25 M dollars with $10 M available as disposable funds for purchase of plant

equipment, supplies, expenses, etc. The Institute consists of 170 people

divided into 15 groups, each specializing in the research and development of a single material. Investigations of the most fundamental kind are the primary

objectives of the Institute's work.

In the case of diamond, two primary activities are ongoing. Technology For

Synthesis of High Pressure Diamond Materials and High Temperature Plasma Jet

Techniques

.

Diamond Growth At High Pressure And High Temperature.

Currently, NIRIM has the most advanced high pressure facilities in Japan for

diamond growth. We were shown a 1,500 and a 30,000 ton press, the latter

capable of attaining 80,000 bars and 2500 °C. Since the initiation of this

program in 1974, considerable progress has occurred in growing large single

crystal diamonds and in determining and controlling the incorporation of

impurities. New catalysts have been discovered for diamond growth and new

methods have been perfected that use carbonate, hydroxide and sulfate salts

rather than conventional metal fluxes such as Ni or Co. Using alternating

carbonate and graphite layers between which diamond seed crystals are sandwiched, the group has succeeded in growing large diamonds. Recently NIRIM

has succeeded in growing small colorless diamonds using magnesium

hydroxide/graphite matrices and calcium hydroxide/graphite matrices at high

temperature and pressure. Work is underway to investigate whether diamonds can be grown at lower temperatures and pressures.

Progress has been made in cBN synthesis by high pressure techniques in which

hexagonal material is converted to cubic material. We were not provided with

the details of this method, although we were shown crystals of the material.

In Seiichiro Matsumoto's laboratory we were shown the most advanced systems to

date for high temperature plasma arc synthesis of diamond. RF powered 70 KW

systems and a DC plasma 100 KW system operating utilizing a CH^ -H2 -Ar feed gas

mixture provided depositions of diamond in a 1.27 cm diameter area at a deposition rate of 2 /nm/min. In addition, an acetylene torch deposition

system was present in this well equipped laboratory.

Microwave Plasma CVD Facilities

Four 1.5 KW microwave plasma systems were available for CVD synthesis. On

these reactors no separate control of the substrate temperature was done. Two more advanced units that looked larger, were being constructed in a laboratory

that we did not enter.

Surprisingly, using no substrate preparation other than washing the silicon

substrate with alcohol. Dr. Sato claimed to obtain excellent nucleation of

diamond. One inch diameter areas of film had been grown. Under microscopic

examination, both large and small distinct diamond crystals were visible on

58
samples where growth had been interrupted before formation of the continuous

film. The growth temperature, which was monitored with an optical pyrometer

that sampled the reactor by a prism coupling through the top of the reactor, was determined to be between 700 and 900 °C.

Characterizations

NIRIM's facilities for growth of diamond vastly outstripped its facilities for

characterizing the materials. SEM is done, but no thermal conductivity

measurements are done. This paucity of characterization tools will soon be

rectified by the addition of new capabilities that are being set-up. Plans to

acquire surface reflection FTIR exists. A new UHV system equipped with

excimer laser assisted photodeposition, in situ RHEED, and Auger spectroscopy

is under construction. A Raman spectrometer is already in operation.

NIRIM needs to collaborate more closely with other groups in order to obtain

comprehensive characterizations of the diamond coatings deposited in its high

deposition rate systems.

NEC "

Date of visit: June 1, 1990

Visiting Delegation: A. Feldman, J. Mitchell, and M. Tamor . .

Background . NEC is a large corporation established in 1899 and subsequently

owned 42% by Western Electric Corporation following World War II. NEC, now

partially owned by Sumitomo, had net sales of $23 billion dollars and included

104,022 employees in 1989. Within its nine research divisions are 1000

employees mostly located at the Kawasaki central research facility. Three

departments reside at the Tsukuba location, where most of the semiconductor

work is done. NEC is expanding with a research laboratory specializing in

artificial intelligence at Princeton, New Jersey and a new laboratory planned

for Osaka

.

Within the Materials Research Laboratory at Kawasaki a broad range of research

is conducted. Ten researchers work on Josephson junction computers, while

fifteen researchers are investigating high T^ superconductor materials. Two

thirds of their device work includes silicon electronics, while one third is

devoted to II-V's.

NEC had a rather impressive area displaying products and technology. A

computer system that does translations into six languages was demonstrated.

High clarity, brightly colored liquid crystal displays on miniaturized TV screens were shown. Technology for networking of supercomputers was diagrammed. A complete 8 in diameter x 4 ft. long single crystal boule of Si was displayed. These were only a few of the items on display.

The Diamond Program . Dr. Shohata, Manager, Materials Research Laboratory,

presented a technical seminar on diamond materials for applications,

possibilities including high fidelity speaker membranes, ultraviolet sensors,

and magnetic disc coatings. NEC's diamond program is two years old and

involves seven people investigating diamond and diamond- like carbon (DLC)

materials. No semiconductor diamond work is underway. However, Sumitomo

59
(NEC's partial owner) is heavily engaged in such investigations. NEC and

Sumitomo are conducting synchrotron lithography research. NEC operates a 10

meter system while Sumotomo has a 3 meter synchrotron. It is quite curious

that neither of these corporations indicated that they are working on X-ray

mask applications for diamond. In view of the fact that the Japanese have

been committed for a long time to the diamond materials for x-ray masks.

Their work is likely to be considered highly proprietary.

An elegant hot filament reactor is in operation. With this specially designed

multiple W wire hot filament reactor, 3 inch silicon wafers had been coated

successfully. Deposition at 0.5 micron/hr at 850 °C substrate temperature in

Ch^ /H2 (1-5 vol %) had been achieved. The temperature of the substrate holder

in the filament reactor (6 in x 6 in) was controlled by separate infrared

heaters. Four 0 . 3 mm W wires were suspended 10 mm above the substrate surface

and kept in tension by specially designed metal posts.

Characterizations

.

Investigation of the dependence of surface roughness of

films on CH^ concentration have been carried out. It was observed by SEM that

a 1% CH^ fraction in a CH^ /H2 feed gas gave crystalline surfaces that improved

in smoothness. When the CH^ fraction was increased to 3%, very smooth

translucent diamond films of 5 micron thickness were obtained. One could read

through these films. Their thermal conductivity was 500 W/m K. Films were well characterized by Raman spectroscopy, and x-ray diffraction. Morphology,

roughness and transmittance were assessed. Thermal diffusivity measurements

were made on thick free-standing diamond films with a commercially available

apparatus.

The NEC group had analyzed comprehensively their diamond-like materials and

had developed advanced facilities for depositing DLC materials. Thermal

studies of DLC showed that these materials continuously lost CH3 and CHj

radical groups as the temperature was heated to 700 "C. Rapid graphitization

occurred at temperatures > 400 "C and the upper temperature limit for DLC was determined to be 430 °C. DLC materials were further characterized by

Rutherford backscattering and recoil methods and found to contain 24 to 32%

hydrogen. An impressive (but perhaps not unequivocal) micro- indenter method

had been applied to determine the apparent "hardness" of DLC. The distance of

penetration of the micro tip was measured by an interference fringe technique

and the applied load was determined by an electrobalance . Both the Vickers

hardness and Young modulus of the films were measured versus the CH4/H2 ratios

used in deposition. Other characterizations included electrical resistivity

(2.8 X 10^"^ ohm cm) and dielectric constant (3.5). The density of the film

prepared in a DC glow discharge reactor was 2 g/cm^ .

The NEC DLC system had a very large chamber, 14 x 14 x 10 in. Plastic holders

in a stacked assembly could be loaded into the chamber. It appeared that each

disk could be automatically transferred from this holder and positioned in the

reactor for sequential coating without opening the vacuum chamber. This was a production type DLC system for coating magnetic disk heads, an application NEC

is about to commercialize. The entire DLC apparatus was housed within semiclean space. This prototype system was considered proprietary. Thus, it was viewed from a distance of 15 to 20 feet. In contrast, we were able to look

inside the hot filament reactor.

60
NIPPON INSTITUTE OF TECHNOLOGY (NIT)

Date of visit: May 30, 1990

Visiting delegation: A. Feldman, R. A. Rudder, M. A. Taraor, and W. A.

Yarbrough

The diamond effort at NIT is over 5 years old, but it has expanded recently.

Five faculty members (3 senior, 2 junior) and five graduate students are working on diamond research. Salaries and overhead are funded by the Ministry

of Education. Some major equipment is obtained from the Ministry of

Education, but most is provided by industrial sponsors. All funding for

studies of coating and testing cutting tools was provided by industrial

sponsors. The sponsors were unnamed, but are likely to be automotive as evidenced by the interest in super-eutectic silicon/aluminum alloys.

Professor Y. Hirose had been on sabbatical at North Carolina State University

during the 1989-1990 academic year. Ironically, the NIT faculty pointed out

that Japanese industry prefers to fund U.S. universities because they are more reliable in performing and reporting the desired research.

Diamond research at NIT is focussed in two areas: chemistry of CVD; and tool

performance and tribology. Approximately 20% of the effort appeared to be

devoted to CVD studies, with the remainder devoted to tool applications. In

the area of CVD chemistry, both hot filament (HFCVD) and combustion flame

reactors are in use. In HFCVD, after demonstrating diamond deposition from a wide variety of hydrocarbon liquids, including sake and bourbon, ethanol was selected as the carbon source of choice. Two large area reactors

(approximately 3 in. diameter) have been built for tool coating, while smaller

reactors (1 in. diameter) are used for deposition research. Professor Hirose

was the first to demonstrate deposition of diamond by an oxy- acetylene

combustion flame. This work is being extended with demonstration of a scanned

flame reactor for coating larger areas and the initiation of studies of

optical emission spectral from the flame.

The facility for evaluation of tool tribology at NIT was unique and quite

impressive. This included a rather conventional lateral scraping device for

measuring film adhesion, and a unique shear tester developed in house for

measuring tool wear. The latter measures the rate of wear of a cutting edge

by repeatedly cutting slivers from the end of a carbide abrasive coated tape.

This instrument has been used to demonstrate quantitative correlation between

film adhesion and cutting edge lifetime. NIT is also involved in fabrication

and testing of tools formed by brazing of CVD diamond plates to conventional

tool inserts. Tools brazed with diamond plates more than 15 microns thick

exhibited performance equal to that of diamond compacts in cutting supereutectic (18%) silicon/aluminum alloy.

NIT also has a somewhat smaller project in cBN. They have deposited thin

films of pure nanocrystalline cBN in a hybrid reactor. This reactor uses a magnetically stabilized, capacitively coupled RF plasma of argon and nitrogen,

along with electron-beam evaporated boron to deposit cBN on a 2 in. diameter

substrate

.

61
NIT faculty indicated that in basic research on CVD diamond and in some applications the United States may enjoy a small lead, but that Japan leads in

most applications by a large margin.

OSAKA UNIVERSITY

Date of visit: June 4, 1990

Visiting delegation: Visited by all members of the U.S. Delegation

The visit was hosted by Professor Akio Hiraki and Dr. Hiroshi Kawarada.

The scale of effort on CVD diamond at Osaka University is impressive. In

addition to Professor Hiraki and Dr. Kawarada, there are 10 graduate students

and post doctoral researchers. The research is directed towards applications

in electronics and luminescent emitters.

The group has been working on CVD diamond for 3.5 years. Their major support

comes from government research grants. A significant portion of the support

for diamond is apparently spin off from a major program on silicon. The Osaka

University group is collaborating with Kobe Steel on electronic properties of

diamond and with Shimadzu Corporation on the development of ECR diamond

deposition sources. The Osaka group, together with Shimadzu, is apparently

selling an ECR source developed and designed at Osaka University. In

addition, the group has coauthored joint papers with researchers from Idemitsu

and Canon. Professor Hiraki has many contacts in the United States stemming

from two prior extensive stays in this country.

The research at Osaka University addresses a number of fundamental issues

including: nucleation and growth, gas phase chemistry, doping, film

morphology, interface properties, and defect structures. They are primarily

interested in the electrical and optical properties and do not make thermal

conductivity measurements.

The group at Osaka University has developed an interesting and novel process

which they call SENTAXY. This process uses a combination of masking, abrasion

with diamond, and ion sputtering to provide diamond nucleation sites at

selected substrate locations. Beautiful arrays of single crystallites of

diamond can be achieved by this method. However, the individual crystals are not oriented with respect to the substrate.

The group is also focusing on the problems of obtaining deposition of high

quality diamond films over wide areas. To accomplish this they are using low

pressure, magnetically confined plasmas. Operation at lower pressures gives a more diffuse, widespread plasma which leads to more uniform deposition over wider areas. However, the low pressure deposition process is accompanied by

much lower growth rates. The growth rate problem was addressed by use of

different chemistry in the plasma, most notably using CO and CO2 instead of

methane. The source gases can be, for example, 85% H2 and 15% CO by volume.

Growth rates of 0.3 to 0.5 /xm/hr have been accomplished using a 5 KW microwave

source operating at 2.45 GHz to generate a low pressure plasma in the presence

of a confining magnetic field; however, the electron cyclotron resonance (ECR)

62
condition is not utilized. The feed gas flow rate was 100 sccra and pressure

was as low as 0.1 Torr.

Substrate temperatures have been reduced to 500 °C and they hope to further

reduce these temperatures to 400° C and lower. The delegation was shown a 4

inch diameter silicon substrate with a diamond film 1 ^m thick covering the

entire surface. The deposition was not completely uniform, because

interference fringes were clearly visible. This film was deposited from a gas

mixture of 5% CH^, , 10% COj , and 85% H2 at a feed gas flow rate of 100 seem. Doping of the deposited diamond films was achieved by addition of B2H5 to the source gas

The Osaka University group is highly committed to the use of microwave ECR

deposition reactors although they usually use fields greater than those needed

to fulfill the ECR condition. They believe that this method has good

potential for scale-up and use in production applications.

Some efforts on heteroepitaxial growth of diamond on silicon carbide were

attempted, but without success. Growth of diamond films from beams of CH3

radicals is also being attempted.

The characterization capabilities at Osaka University are extensive. These

include Raman spectroscopy, x-ray diffraction, electron microscopy. Auger

spectroscopy, cathodoluminescence , photoluminescence , and Rutherford

backscattering. Hydrogen content in diamond films is determined by forward

scattering in the Rutherford backscattering facility, which is equipped with a 3.5 MeV ion accelerator. This apparatus is also used for ion channeling

experiments

The visiting team was greatly impressed by the quality of the entire effort at

Osaka University. This is a world class research team under the direction a very energetic and capable leader.

SEIKO INSTRUMENTS INC

Date of visit: May 30, 1990

Visiting delegation: J. C. Angus, S. Holly, J. W. Mitchell, and K. A. Snail

Dr. Kohji Asakura, Senior Engineer at the Rockwell International Overseas

Corporation acted as interpreter and guide.

Mr. Hiroyuki Funamoto, Manager of the Process Development Section, met us at

the train station and served as a contact person throughout our visit. Mr.

Yoichiro Sakami, Director of the Technology and Project Administration

Department was our primary host.

Each of the visiting team give a very brief overview of our own diamond

efforts. Mr. Funamoto then gave a very informative and extended discussion of

the Seiko effort in diamond and diamondlike materials.

Seiko has been working on CVD diamond since 1984. The goals of their research

are specific products. These include: heat sinks, protective coatings.

63
printer head coatings, and x-ray windows. Three full time research employees

work on CVD diamond at Seiko.

Seiko believes itself to be a relatively small player in the CVD diamond

field, and, therefore, relies heavily on cooperative efforts with other

institutions. Initially, they cooperated with on NIRIM and on the Japan

Research and Development Corporation. They are also cooperating with

universities, including the Tokyo Science University. They spoke very highly

of their joint venture with Air Products and Chemicals Corporation for the

development of diamond- like films for protective coatings. (NOTE: A new

company, Diamonex has been formed to carry on the diamond and DLC work

formerly done at Air Products and Chemcials.) The positive nature of this

relationship was emphasized several times during our visit.

The research effort at Seiko is very heavily weighted toward applications

rather than fundamental research. They have strong efforts in measuring the

mechanical, thermal, and optical properties of the diamond films. They are also concerned with film morphology and surface finish. They are investigating ion etching and other processes for polishing the films.

Seiko is using only microwave plasma CVD processes for depositing diamond

films. Ion beam processes for deposition of diamondlike materials are being

conducted in the United States by their partner, Air Products Corporation.

They indicated that their substrates were prepared by scratching. Deposition

temperatures range from 700 to 900 "C. Film characterization measurements

include thermal conductivity, density, Raman spectroscopy, x-ray diffraction,

scanning tunneling microscopy, and hardness. They did not mention any work on

cBN

.

Seiko apparently will be using microwave deposition for its scaled up

commercial processes. It believes that an important technological barrier

still to be overcome is the deposition of high quality films with the highest

possible thermal conductivity. Heat sink applications for CVD diamond are still two to three years away according to Seiko. However, applications of

diamondlike films are expected very shortly. The first applications of the

diamondlike films will be coatings for scratch resistant watch faces. This

could be a significant market, since Seiko makes 55 million watches per year.

The Seiko representatives indicated that the diamondlike film coating work

would be done by their partner. Air Products and Chemicals, in the United

States, while any CVD diamond application work would be conducted in Japan.

The visiting delegation was taken on a very interesting tour of the Seiko

facilities. We saw two robotic, pilot production lines for the production of

watches. These automated production facilities were most impressive. We then

were taken to the laboratory areas were the CVD diamond was produced and also saw their highly developed method for measurement of thermal conductivity of

diamond films. The deposition system appeared to be what is now called the

standard NIRIM microwave system.

The entire visiting team came away with a very great respect for the

competence and energy with which Seiko Instruments is pursuing research and

development in CVD diamond. Their level of effort and sophistication is

especially noteworthy because they are not a giant corporation with

exceedingly large resources.

64
SEMICONDUCTOR ENERGY LABORATORY (SEL)

Date of visit: June 1, 1990.

Visiting delegation: J. C. Angus, J. J. Cuomo, S. Holly, and R. A. Rudder

The visit was hosted by Dr. Shumpei Yamazaki, President of SEL, who briefed

the delegation on the history of SEL and its current business. Dr. Yamazaki

has applied for more than 1700 Japanese and 600 U.S. Patents. Yamasaki is one of the three founders of electronically programmable read only memories

(EPRDM) . His application for a diamond CVD patent in 1981 using RF or microwave plasmas is dated several months prior to NIRIM's hot-filament

application. His company demonstrated diamond CVD growth in 1984. Despite

this auspicious diamond start, SEL sought business opportunities other than

diamond. Today, of its 130 employees, only 4 or 5 work on diamond CVD

development. Its major business areas are solar cells, image sensors, photo

sensors, large size liquid crystal displays, and photo -enhanced or plasmaassisted CVD apparatus.

Before discussing the diamond technology at SEL, it is worthwhile to discuss

the SEL business strategy. Our visiting delegation found the concept of SEL

and its management as intriguing as the diamond technology. SEL is a research

and development warehouse. It uses revenues returned from patent licenses and

royalties along with income from contractual sale of technology to industry to

seed research and development in new technologies. As these technologies

develop, patents are applied for to establish SEL's position. The processing

technology or materials technology are marketed to industrial clients. SEL

sees itself as a global company willing to export its technology around the

world. SEL's product is its technology for a particular process. It delivers

to industry primarily equipment and instruction but will undertake to have SEL

personnel assist people at the clients location. SEL has no government

contracts. SEL is in a position to market its technology world-wide.

Dr. Yamazaki perceives the world economy divided into three sectors:

agricultural and raw materials; services; manufacturing. By this

segregation, he describes his company as a "2.5" company, providing research

and development services to manufacturing companies around the world. SEL

entered the diamond CVD technology by delivery of a prototype low pressure ECR

system to Osaka University. SEL currently offers for sale a mixed cyclotron

resonance diamond CVD apparatus for deposition onto 100 mm Si wafers. It

currently has delivered 5 units to customers. Diamond CVD equipment is not

the only CVD equipment marketed by SEL. It currently sells photochemical CVD

equipment for silicon nitride deposition.

Diamond research and development at SEL is not the major product at SEL. SEL

stated that it had one person devoted to diamond R&D and that it had 5 people

active in DLC R&D. The committee perceived perhaps 2-3 people active and

conversant with the diamond CVD effort. Besides activities in diamond, DLC,

silicon nitride, SEL has activities in high T^ superconductors and solar

cells. Areas other than diamond constitute a larger market for SEL.

Yamasaki does not foresee immediate development of electronically active

devices. He does see the potential for diamond heatsinks for other

65
semiconducting devices. He is not optimistic about diamond light-emitting

devices. He does foresee diamond technology for cutting tool coatings, wire

dies, protective coatings on windshields, and for photomasks on UV exposure

systems. Diamond n-type doping must be achieved if there is to be significant

electronics application.

For large area coatings greater than 100 mm in diameter, a microwave source with power output greater than 5 KW must be designed in order to maintain the

plasma density necessary for diamond deposition. Currently, SEL can deliver

systems to clients which grow diamond films uniformly over a 100 mm Si water.

The rates are approximately 0.5 /im/hr. The substrates are subjected to a diamond ultrasonic treatment prior to deposition. The lowest deposition

temperature for diamond occurred between 330 and 470 "C using methanol in the

feed gas. The films are characterized by SEM, Raman, XRD,

electroluminescence, and cathodoluminescence . The optimization of their ^ process has occurred both through the aforementioned external

characterizations and by use of atomic emission spectroscopy. By inserting a light probe into different regions of the ECR discharge, SEL has determined

the parameter space in power, pressure, and substrate bias whereby one can obtain uniform 656 nm atomic hydrogen emission over a 100 mm diameter. VThile

not basic research, this is an example of the high quality of engineering

research performed at SEL. Results of this study, while not yet published, were openly discussed and displayed to the visiting delegation.

The delegation received a laboratory tour of facilities, copies of Japanese

patents on diamond processing, product literature and prices, SEL publications

on diamond, and corporate charter and financial status information. We were very impressed with the company. Its intrepreneurial nature makes certain

that as diamond technology develops at SEL, it will be immediately available

to the diamond industry.

66
SHOWA DENKO K. K.

Date of visit: May 30, 1990

Visiting Delegation: J. J, Cuomo, J. T. Glass, L. H. Schwartz, and C. M.

Stickley , ,

The visit was hosted by Dr. Junichi Sato, Chief Staff Manager of Ceramics

Division. Also present were Dr. Kunio Komaki, Deputy Chief Researcher of the

Central Research Laboratory, Shingo Morlmoto, Deputy Chief Researcher of the

Central Research Laboratory, and Masataka Yamamoto, Deputy Chief Manager of

the Ceramics Division. We met at their corporate offices and thus we saw no facilities nor were we shown pictures of facilities.

Showa Denko (SD) is a producer of olefins, plastics, organic chemicals,

inorganic chemicals, gases, biotechnology products, electronic materials,

carbons, ceramics, nonmetallurgical aluminas, aluminum, and metallic

materials. The company had 1989 total sales of $3.6B and 5000 employees. Its

current 5 year plan (1989 to 1994) calls for achieving an annual sales level

of $4.5B by 1994 and to have invested over the five year period, $0.96B in R&D

and $1.72B in plant and equipment. Assuming a constant fraction of R&D

investment to sales over this five year period implies a 4.8% R&D to sales

ratio. Only internal funds are used for R&D (i.e., MITI , etc., funds are negligible) . Their interest in diamond is broadening from producing diamond

powders (with varying particle shapes) to objects closer to finished products

such as free-standing parts, including cones for high frequency speakers.

Dr. Komaki gave a presentation which summarized a publication they had

published in the 1990 New Diamond Forum proceedings entitled "Multi- shaped and

Hybrid Diamond Particles by Vapor Phase Method." The article reports that

"using (the) hot-filament method we have developed several ways to control

diamond particle morphology by nucleation and growth conditions, resulting in

large single crystal-like and multi-shaped particles. We have also produced

diamond- ceramic hybrid particles in a continuous process." SD has licensed

the patent for this deposition process from NIRIM. The company is utilizing

the combustion flame method to produce particles of different shapes. Dr.

Komaki stated that SD owns the patent for this process having paid for the

development of it with Prof. Hirose at the Nippon Institute of Technology.

For the hot filament approach to making diamond particles they used a feed gas

of ethanol mixed with H2 and a filament temperature of 2800 "C to produce

cubo- octahedral particles. They have modified their process by adding a fluidized bed to suspend other ceramic particles (SiC typically) for coating

with diamond films, SD has U.S. and Japanese patents on the fluidization

process

.

Further, they have modified the combustion flame method, which normally

operates in the open atmosphere, to operate in a chamber (the chamber flame

method) in which C2H2 and (in the ratio of 1 to 0.87) burn at a pressure

ranging from 760 Torr down to 300 Torr. The diamond growth area is 60 mm^ at

470 Torr. The thickness is typically 50 and independent of specimen length

(up to 10 mm); one hour is required to grow the film, which is densely packed

and will stand alone. The film will grow thicker with time; they have grown

films as thick as 0.2 mm.

67
Using Sic chips coated with diamond by the chamber flame method, they have

machined Al-18%Si alloys at turning speeds up to 1500 RPM. These chips show

good durability having turning distances of 60 km. The chip lifetime is 100

times the lifetime of uncoated chips. Adhesion strength, variations in

adhesion strength, surface roughness, and development of a production

capability are improvements that are needed.

With regard to other materials, they state that titanium nitride coatings show

excellent cost/performance ratios. They are just beginning to work on cBN

coatings and have developed a laboratory- level process to make these coatings.

They state that cBN coatings have problems similar to those of diamond - poor

surface finish and inadequate adhesion. SD seems to be pursuing surface

preparation and pre -coating techniques to control nucleation and growth.

Mr. Morimoto presented a review of their work on "Free Standing Diamond Films

- Plates, Tubes, and Curved Diaphragms." This was presented at the Diamond

Optics SPIE meeting in San Diego in August 1989. By shaping (curving) the hot

filament and rotating the substrate (silicon) they have made bowl-shaped parts

as large as 6 cm in diameter and pipes 10 mm in diameter. Microwave CVD is

used to make plates 1" in diameter and 20 microns thick; diameters are expected to increase to from 2 to 6 inches. The bowls are principally diamond

as seen by Raman spectra; However, they appear darker then other parts

indicating a higher graphite content. With this technique they make speaker

cones for Pioneer; they are close to a production process. They will develop

their own equipment for production.

SD has worked with Professor Yoshikawa of TIT on a polishing technique and

have applied to patent the technique in the United States. It involves

rubbing the surface to be polished against a rotating iron plate heated to

700-800 °C in 30 Torr of . With this process they can achieve a surface

roughness of 0.01-0.05 microns in 10-20 minutes; the more conventual

techniques (diamond paste and unheated iron in H2 ) yields a roughness of 1-2

microns after several hours of polishing. They claim this easy to accomplish

on a laboratory scale.

The patent for this process is the only one they have applied for due to the

high cost of patenting involved. They have 10 applications in Japan for

patents on the combustion method, and several have been granted already.

Each department administers its own R&D, but long term R&D (5 to 10 years) is

done by the Central Research Laboratory. Related divisions cooperate in

advising the Central Research Laboratory about its program. The commercial

departments at SD have a 3-5 year perspective.

68
SUMITOMO ELECTRIC INDUSTRIES, LTD.

Date of visit: June 4, 1990

Visiting delegation: Visited by all members of the U.S. Delegation

The visit was hosted by Dr. Akio Hara, Managing Director of the Sumitomo

Electric Itami Works. Dr. Hara explained the functions of their corporate

division as well as the company's strategy for developing new areas of

business through research and development. Sumitomo's commitment to research

is reflected in its budget; 4% of it's operating budget and 10% of its

manpower are dedicated to research and development. Sumitomo makes strategic

choices of research areas to pursue when it envisions developing commercial

markets in those areas. It also recognizes that the size of the commercial

market cannot be forecast at the time the R&D decisions are reached. It

depends on the developing technology to spawn new products and ideas that will

expand the commercial market. Sumitomo then maintains a long-term commitment

in support of the research.

Diamond R&D at Sumitomo is an excellent example of this selection process.

CVD diamond work began at Sumitomo in 1980. Today, more than 10 people are involved with diamond CVD. Five hot filament and 7 microwave plasma CVD

systems are in operation. No CVD diamond products had been introduced to the

marketplace until 1987. The following is a list of CVD diamond products

produced by Sumitomo Electric and the dates they were introduced to the

market. , ,

1987 - diamond- coated loudspeaker diagrams . : : 1989 - diamond- coated endmills

1990 - tape automatic bonding tools (TAB bonders)

''

' "'

,

' ,

• . I f A new product will be announced at the end of the year. - . ;

This development has been supported largely by internal Sumitomo funds . The

combination of both CVD diamond research and HPHT diamond research has allowed

them to set goals for the CVD technology whereby it can become economically

competitive with high pressure technology. Sumitomo has projected the sales

markets for diamond tools at approximately $12.5 M/yr. Even now, the company

believes the technology to be too immature and the markets too poorly defined

to allow for sales estimates of optical or electronic products.

Sumitomo applies four criteria for commercialization of a product. One,

Sumitomo must be creative in developing technologies. Two, there must be

efficient and quick information exchange regarding technological problems and

accomplishments. Three, cost reductions occur when products are constantly

being produced. And four, a company must have patience. For any new

technology, there is a long incubation period before the realization of

products. Sumitomo supports new technologies through that period.

Sumitomo maintains creativity in technology by supporting R&D in the basic

process technologies and by extracting the most from its researchers abilities

and its collaborations with many universities. Sumitomo is collaborating with

NIRIM and Penn State University on homoepitaxy, with Osaka University and the

University of Michigan on optical properties of diamond, and with the Library

69
and Information University on electron spin resonance characterization of

diamond. Sumitomo seemed receptive to future collaborations with U.S.

institutions and industry.

Sumitomo supports efforts in CVD diamond for a multiplicity of applications,

for example: wear resistant coatings, coatings as on cemented carbides,

coatings on ceramics, coatings on wire dies for the pulling of high

superconducting wires. It supports knowledge bases for polycrystalline and

single crystalline diamond deposition, for applications and markets. A

knowledge base on applications and markets is developed by introducing a product to the consumer, by using feedback from the consumer to improve the

product and then by resubmitting the product to the market.

Having the knowledge base obtained through 10 years of development in CVD

diamond and HPHT diamond puts Sumitomo in a unique position to assess the

status of CVD diamond technology relative HPHT diamond technology. In

assessing the economics of diamond production one must consider the efficiency

of the process, the production rate of a process, and the quality of the

product produced.

Many CVD processes make inefficient use of the carbon in the reaction species

because the percentage of carbon converted to diamond is small. Hot filament

CVD converts only about 1% of the carbon available in the feed gas to diamond

whereas the HPHT process converts about 70% of the carbon to diamond.

The production rates of different processes vary widely. The plasma jet

process can produce diamond at rates comparable to or exceeding those in HPHT

cells. However the quality of the CVD material is generally poorer than the

quality of the HPHT material.

The large gas consumption of the high rate CVD processes makes costs high

unless gas recycling techniques can be developed. Sumitomo has currently

established critical goals for diamond CVD at growth rates greater than

90 /xm/hr. These are deposition areas larger than 500 cm^ and deposition

temperatures below 450 *C.

Sumitomo relies heavily on microwave plasma and hot- filament techniques for

diamond deposition. The microwave plasma technique is preferred for

electronic applications where high crystalline purity is important. Hot

filament deposited films contained 20-30 parts per million tungsten

contamination

.

Sumitomo is experimenting with DC bias of the substrate during filament

depositions, a process that appears to be the same as EACVD. Besides the

filament and microwave techniques, Sumitomo is developing a plasma technique

using 02/CH^ discharges with 60% O2 and 40% CH^ . With this ratio of CH4 to

O2 , the spectrum from the discharge contains significant atomic hydrogen

emission. Raman spectroscopy of the deposited diamond shows a dominant 1332

cm" ^ line with a small amount of disordered carbon. Deviations from the feed

gas ratios reduce the hydrogen emission and the quality of diamond as determined by the Raman spectrum.

Sumitomo has succeeded in achieving heteroepitaxial growth of diamond on cBN

(100) and {111} surfaces. The heteroepitaxy was determined via RHEED

70
observations of the deposited diamond layer. The RHEED patterns could best be

described as elongated spot patterns suggesting some roughness to the surface.

No other data, such as micrographs of surface morphology or analysis of the

surface chemical were given. Homoepitaxial growths as a function of CH/,

fraction in the feed gas on different substrate orientations were discussed. • The best morphology occurred on {100} diamond surfaces. RHEED and Raman

analysis showed the optimum growth conditions to be at a 6% CH^, fraction in

the feed gas. RHEED patterns at 6% CH^ were uniformly streaked, and Raman

analysis did not show any amorphous carbon present. Amorphous carbon was found in the films deposited with other CH^ fractions. A number of dopants

were evaluated: B, S, P, CI, As, and Se. P doping resulted in n-type electric

conduction but the electrical conductivity of the films was very low. The

activation energy of the boron doped samples was observed as a function of the

dopant concentration in the gas phase. The results are given in the GENERIC

RESEARCH section of this report.

Mobility as a function of temperature was reported for one of the boron doped

films. The hole concentration was 10^ "'/cm'^ at room temperature increasing to

10^®/cm^ at 600 °C. The hole mobility was 960 cm^/V/s at room temperature

declining to 70 cm^/V/s at 600 'C.

Diamond MESFETs were also fabricated from boron doped films. The gate length

and width were 80 /xm and 150 urn, respectively. Ti was used for ohmic contact

to the source and drain while W was used for the Schottky contact. Transistor

behavior was observed on a metalized 1/im thick p-type layer, but the source to

drain current was extremely small. An increase in the source to drain current

current occured when a 0.23 /zm intrinsic diamond layer was deposited over a 0.90 ;im p-type layer prior to metalization. The operation of these

transistors at elevated temperatures was not reported.

Future work at Sumitomo is targeting perfection of epitaxy, fabrication of

practical devices, and the fabrication of he teroj unction devices. The

committee was impressed with the CVD diamond effort at Sumitomo.

TOKYO INSTITUTE OF TECHNOLOGY (TIT)

Date of visit: June 1, 1990

Visiting delegation: J. T. Glass, C. M. Stickley, K. A. Snail, and L. H.

Schwartz

Two groups are working on diamond at TIT. The first is Professor Osamu

Fukanaga's group; his group's research focuses on reducing pressures required

for HPHT synthesis of diamond into the 3-4 GPa range using novel catalystsolvents (e.g., carbonates). This work is being done in collaboration with

NIRIM. His group's other line of research focuses on alternative ways of

enhancing surface mediated reactions in a CVD environment. His primary

approach is to vary the power in a microwave reactor and look for changes in

the stress of the deposited material, as measured by Raman peak shifts.

The second group, which is headed by Professor Masanori Yoshikawa, is focussed

on tool and abrasive grit applications. This group has achieved a number of

firsts with little government support and/or equipment. The main

accomplishments are: The highest reported growth rate for CVD diamond.

71
920 /im/hr - 10 KW in a DC plasma jet; and, the development of a novel

technique for polishing CVD diamond with hot iron. They are also cutting and

planing CVD diamond with a pulsed Nd: Yag laser. They are able to smooth films

to 2-3 ^m average roughness with a laser and can cut 100 /zm deep grooves with

modest laser powers (7-8 W) . We recieved two publications from Professor

Yoshikawa on the laser processing (in Japanese).

Professor Yoshikawa claims that his DC plasma jet can grow diamond at a cost

of about 100 Yen/carat, or less than the current price for HPHT grit. After

hearing the presentation during our visit to Sumitomo Electric, there is some skepticism about this claim. Professor Yoshikawa has broken up his diamond

deposits using steel rollers and has bonded the grit to wheels for cutting.

Using a Nd:Yag pulsed laser, he has cut and smoothed diamond films synthesized

with the DC plasma jet; the films were then brazed to cutting tool inserts.

Professor Yoshikawa 's polishing technique is very simple and is claimed to be

able to polish the hard <111> face of natural diamond. The technique involves

polishing the diamond in a chamber on a hot (700 to 900 °C) iron lap in the

presence of hydrogen and near a hot filament. Professor Yoshikawa now says he

does not need a filament in his chamber; he can polish CVD diamond at a rate

of 6 fim/hr at 900 "C. Some prepolishing at lower temperatures may be required

because experience at NRL indicates that the high applied forces needed for

polishing diamond, in combination with the high temperatures, can cause scratching of the iron disk if the CVD diamond is too rough.

72
TOSHIBA TUNGALOY INC.

Date of visit: May 30, 1990

Visiting delegation: A. Feldman, J. W. Mitchell, M. A. Tamor, and W. A.

Yarbrough

Toshiba Tungaloy is a moderately sized organization (approximately 245 million

dollars in 1989 sales) specializing in the design and production of coated

cutting tools of numerous types and designs and has its principal production

and research facilities in Kawasaki, Japan near Tokyo. In recent years they

began to market CVD coating equipment for conventional tool coatings

(TiN/TiCN/Al2 03 ) in addition to their principal cutting tool business. It was originally founded in 1934 and was reorganized in 1950 as spin off of Toshiba

Corp. by Messrs. Momma and Ando . The latter is currently President and CEO.

They have been pursuing CVD diamond coatings for tool applications since

approximately 1984 under the leadership of Dr. Sokichi Takatsu, their chief

engineer for materials. They have collaborated with numerous other research

and development organizations, supporting research at several locations in

Japan and the United States and have presented their work at numerous

technical meetings and conferences. They are presently members of the Diamond

and Related Materials Consortium at the Pennsylvania State University and have

invested in both production and marketing facilities in the United States with

a recently completed facility in Evanston, IL. They have affiliated

subsidiaries in the United States under the names of Toshiba Tungaloy America

Inc. and Toshiba Tungaloy Manufacturing Inc.

Production scale CVD deposition equipment (for conventional tool coatings) is

marketed in North America and Europe by means of a joint venture with

Lindberg, and this was discussed during the meeting. Toshiba Tungaloy is

aggressively pursuing scale up strategies for microwave and hot filament

deposition methods, and when asked, indicated that although no decision had

been reached, they might well market a production scale reactor for diamond if

a proprietary production reactor technology was developed. The team was not

permitted to inspect their current large scale equipment, but was permitted to

inspect microwave pilot equipment (~ 6 inch capability) which appeared similar

in design to equipment built by Showa Denko. The focus of most of the work

discussed was on methods and strategies for achieving good adhesion to high

cobalt containing (8-12%) cemented carbide tool base materials. Strategies

discussed included the removal by etching of cobalt from the surface of the

tool materials followed by diamond deposition by both microwave and hot

filament techniques. In addition they have experimented with sintered

tungsten carbide (cobalt free) using a method by which the carbide surface is

first decarburized in H2 . This surface is then recarburized in the initial

stages of diamond deposition producing a very finely crystalline tungsten

carbide at the surface. Diamond nucleation then proceeds on this surface with

a mechanical interlocking of the carbide and diamond. This was demonstrated

to the team through some very excellent cross section electron microscopy.

They reported that adhesion strength is improved by this technique and that a mechanical "interlocking" of the diamond layer with the underlying pore

structure of the etched carbide tool base, or as the result of decarburization

followed by recarburization on diamond deposition, is primarily responsible

for this improvement. The best results with an etching strategy were obtained

when the grain size of the diamond coating was similar to the sizes of the

pores left in the tool surface. Cutting tests have been performed and

73
satisfactory performance achieved in cutting of high silicon aluminum alloys

(10% Si). Adhesion is measured using a number of methods including an indentation method with a diamond Rockwell hardness cone. Although diamond

coated lathe inserts for the automotive industry were obviously an immediate

product interest, of considerably greater interest were methods for highly

adherent diamond coatings for use where interrupted cuts were needed, e.g.,

surface milling operations, and where adhesion strength remained a concern.

In addition, the surface modification of diamond to render it suitable for

high speed ferrous metal machining was also discussed with obvious interest on

the part of Toshiba Tungaloy personnel.

Considerable interest was expressed in the development of c-BN coatings in

addition to diamond and, although some work has been pursued at Toshiba

Tungaloy, it was considered too immature to report or discuss. It was noted

however that they have been evaluating "cubic" BN coatings from a number of

sources and have been attempting diamond deposition on them. In most cases,

adhesion of these coatings to carbide tool bases has been unacceptably poor

and difficulties were reported in nucleating diamond on many of these

coatings

.

74
APPENDIX D

Admins tration of Science and Technology in Japan

In recent times Japan's technological system has been studied [1], modeled,

and sometimes copied, perhaps more than any other. The reasons for this are many and stem from their industrial achievements which have led to

international marketplace dominance in areas such as consumer electronics or impending capture of markets like semiconductor chips and devices. Their road

to success is for the most part a Japanese "road" especially built to match

their culture, traditions, and particularly, their technical status and needs.

In the main, their industrial policy, fueled originally by profits from

captured markets (e.g., steel, shipbuilding), has been directed not at failing

or stagnant industries, but at the new opportunities and the strengthening of

already vital, expanding private industrial segments. Currently Japan has

reached a juncture in its industrial development, as past goals have been

achieved and technological leadership or equality obtained. Long-term

planning has been a key feature of their industrial strategy with the future

the primary concern, not saving or recapturing the industrial past. Questions

relative to Japan's current technological status are addressed at the cabinet

level leading to frequently updated general S&T guidelines. Its S&T (and by

implication, MSE) system is conceptually steered towards rapid technological

leapfrog advancement or catch-up through technology purchase and enhancement

(e.g., manufacturing R&D), not strictly maintenance of a leadership position,

like that of the United States. Hence basic research had not been emphasized

previously, but now a more broad-based research front is viewed as necessary

for additional/new advancement. Changes in this direction are already

underway for certain key industrial areas like advanced materials and

information technology.

The Japanese S&T and MSE establishment is a highly structured enterprise,

instrumental in numerous past technological successes and highly capable of

more in the future. It is comprised, however, of conventional organizational

elements and implementation/strategy instruments not too dissimilar from those

available and used throughout the world. What is atypical to Japan is its

systems approach -- its long-term and consistent policy, stimulated and

coordinated by government but coupled to an effective communication link

between the public and private sectors, including a multi- level

advisory/committee arrangement. The term 'cooperative' has been frequently

used to describe Japanese R&D. A better descriptor might be 'orchestrated

division of activities and responsibilities' with government acting as the

catalyst and industry taking a lead role as a funder and performer of R&D. As

the research turns more product-oriented, cooperation in proprietary areas is

almost minimal and company- to -company competition is intense. Communication,

consensus , and common action by leaders for the national good is always

maintained through the committee/public forum system, but never through paid

lobbies, as this is not an allowed practice in Japan.

* Based on material from "International Cooperation and Competition in

Materials Science and Engineering," NISTIR 89-4041, June 1989, updated with

information from NSF's Tokyo Office and the visits made by members of the

Diamond Technology visiting team.

75
Within government, the highest policy making body for S&T is the Office of the

Prime Minister [1-3] . Chart Dl identifies the major government organizations

in Japan responsible for S&T. Two advisory councils, the Science and

Technology Council (Kagaku Gijutsu Kaigi) and the Science Council, provide

guidance on S&T and on pure science matters. The membership on these councils

are made up of leading spokespersons for S&T in government and out;

chairmanship resides with the Prime Minister of Japan. These councils

establish national goals and provide broad directions for S&T (and MSE) and,

in general, decide S&T issues of national import. Overall the councils have

great impact on Japan's federal S&T yearly budget of about ¥1.8 billion in

FY89, (Table Dl)

.

Table Dl. Yearly Comparison of Japan's Federal S&T Budgets [4]

Japanese Fiscal Year Budget(in billion yen) % Change

1985 1,532.9 3.3

1986 1,606.4 4.8

1987 1,662.3 3.5

1988 1,715.7 3,2

1989 1,815.6 5.8

1990 1,919.6 5.7

Two ministries (MITI and MOMBUSHO) and one agency (STA) essentially share

government operational responsibilities for S&T, including planning, funding,

and oversight. In addition to these, two others provide a check and balance

mechanism. The Federal Trade Commission governs on the legality of business

practices and often judges/rules on MITI plans and activities. The Ministry

of Finance approves all budgets and justifications for enhancements and

baseline support:

Science and Technology Agency (STA) This agency is located within the Prime

Minister's Office. It receives about 26% of government R&D funds [4] for

major national projects like the space and the reactor programs. The agency

also has the charge to stimulate basic research within industry, and through

its Japan Research Development Corporation (JRDC) to support new technology

developments (Exploratory Research for Advanced Technology- EEIATO) using startup companies as one implementation mechanism. Attached to STA are six

research institutes, two of which, NIRIM (National Institute for Research in

Inorganic Materials) and NRIM (National Research Institute for Metals) are the

principal laboratories most related to MSE. Although under STA, they often

perform R&D in cooperation with MITI, the industrial-oriented ministry.

The STA has no special "line- item" which is designated for the promotion of

artificial diamond research. Rather, the decisions to carry out work in this

76
CHART Dl. MAIN RESEARCH ORGANIZATION ON SCIENCE AND TECHNOLOGY IN JAPAN

Cabinet Priiae Minister's Office

Science Council of Japan

Council for Science & Technology

Atomic Energy Coanission

Nuclear Safety Coanission

Space Activities Comilssion

Council for Ocean Development

Science & Technology

Agency

Resources Council Consulting Engineer Council

Council for Aeronautics, Electronics S Other Advanced Technologies

Radiation Council

Attached Research Inst. National Aerospace Lab National Res. Inst, for Metals

National Inst, of Radiological Sciences

National Res. Center for Disaster Prevention

National Inst, for Research in Inorganic Materials

National Inst, of Resources

Public Corporations

Japan Atomic Energy Res. Inst. (JAERI) Research Development Corporation of Japan (JRDC)

Power Reactor and Nuclear Fuel Development Corporation (PNC) National Space Development Agency of Japan (NASDA)

Japan Information Center of Science

& Technology (JICST) Japan Marine Science & Technology Center (JAMSTEC)

Institute of Physical and Chemical Research (IPCR)

Ministry of Education

Japan Academy

National Science Museum

Science Council Geodesy Council

Council for Science Education

& Vocational Education

National Inst, of Genetics

Inst, of Statistical Mathematics

Intl. Latitude Observatory

National Universities

Japan Society for the Promotion of Science (JSPS)

Ministry of International Trade & Industry Industrial Technology Council

Patent Office

Agency of Natural Resources and Energy New Energy Development

Organization (NEDO)

Agency of Industrial Science & Technology

National Res. Lab of Metrology

Mechanical Engineering Lab. National Chemical Lab. for Industry Government Industrial Res. Inst. Osaica Government Industrial Res. Inst. Nagoya

Fermentation Res. Inst.

Res. Inst, for Polymers & Textiles

Geological Survey of Japan

Electrotechnlcal Lab. Industrial Products Res. Inst. National Res. Inst, for Pollution & Resources Government Industrial Development Lab Hokkaido

Government Industrial Res. Inst. Kyushu Government Industrial Res. Inst. Tohoku Government Industrial Res. Inst. Shikoku Government Industrial Res. Inst. Chugoku

and other organizations

SOORCE: Combined Information from [JTECH 1986; Ceramics

JFCC Information Package 1987] Japan 1984;

77
area at NIRIM and to stimulate its commercialization through the JEIDC are consequences of program evaluation made by the leadership of NIRIM and JRDC

.

These decisions are evaluated by the STA in the context of overall mission

plans for the Agency in support of science and technology, and, in particular,

in the context of a remarkable document referred to by our host at STA as the

"Bible" on materials. The current version of this document, entitled

"Government Research and Development Plan on Substance/Material Series of

Science and Technology" was published on October 22, 1987, and is attributed

directly to the Prime Minister of Japan. The "Bible" on materials is

remarkable in its simplicity, consisting of only 21 pages of prose which

define the goals for STA while giving maximum flexibility to the program and

laboratory managers to achieve these goals. Operating under these general

guidelines, annual budgets are constructed including long-term multi-year

funding dealing with specific research goals.

The Research Development Corporation of Japan (JRDC) , a subsidiary of STA, was founded in 1961 as an organizer of research and development projects

encompassing governmental research institutions and universities. Its

principal roles and associated budgets in FY 1989 are Development of New

Technology (including licensing) at Y4.5B, Exploratory Research for Advanced

Technology (ERATO) at ¥6 . OB , and a new program promoting International

Research Exchanges at ¥0.9B. Among the 14 current ERATO projects are no less

than seven dealing with materials: nano- mechanism (physical and mechanical

properties of nano-size particles and the materials they yield); solid surface

(methods of modifying surfaces by chemical or photochemical reactions)

;

molecular dynamic assembly (science underlying self -assembling materials);

molecular architecture (structural issues related to bio-materials) ; quantum

wave (quantum wave effects in quantum microstructures) ; micro-photoconversion

(use of laser light to bring about new processing in various areas including

materials processing); and, atom craft (manipulation of single atoms or groups

to form materials)

.

JRDC's technology development efforts are significant and worthy of study by

any organization that proposes to emulate their mission of moving government

funded R&D into commercial application. It is noteworthy that the source of

their portfolios of technologies (313 specific projects have been funded for

technology development since initiation in 1961) is 51% from universities, 32%

from national or public research institutes and 10% from public research

foundations. Projects span the technological spectrum with 7% in metallurgy,

9% in measurement instruments, 21% in electrical engineering and electronics,

etc. One measure of success of the process JRDC uses for selecting areas of

investment is the fact that of its current budget about 42% was derived from

repayment of loans for development funds and revenues from licensing.

Ministry of Education. Science and Culture (MOMBUSHO) This ministry accounts

for about 47% (in FY87) of government research funds [NSF-Tokyo Office 1987],

the total of which is provided to the universities and national centers for

scientific research. University research is supported directly by funds based

on formulas (e.g., number of professors and other similar factors), peer

reviewed research proposals, and by allocations according to salary costs,

building facilities, and large-scale instrumentation. University- industry

interactions are minimal (a problem recognized by MOMBUSHO) since paid

consulting by professors is not allowed nor is joint university- industry

78
research a common practice. (However, in the area of diamond technology there

are important collaborations between university professors and industry.)

Ministry of International Trade and Industry (MITI) This ministry is the

central government organization having industrial development as its primary

charter. It receives only about 13% of government R&D funds, relying on cooperative mechanisms with industry to leverage considerably more R&D. MITI

formulates industrial technology plans, determines and provides for subsidies

and/or funding and selects/persuades/organizes participating industrial R6tD

groups/associations to work with one or more of MITI ' s 16 national labs. The

national labs fall under the jurisdiction of one of MITI's operational arms,

AIST (Agency of Industrial Technology and Science). A sister agency, JITA

(Japan Industrial Technology Association) functions as the licensing agency of

AIST and provides regular information on foreign technology developments.

Typical of MITI's procedural mode is their program on advanced materials. The

program, under the auspices of AIST, targets three general research areas,

biotechnology, electronics devices, and new materials. In the general case,

AIST forms a non- government advisory committee for each project and an industrial association is created to work cooperatively with all other members

of the organization and MITI's national labs. Selection of participating

companies is made by AIST based on financial standing, reputation, and R&D

ability. Its budget is controlled by MITI, but supplemented heavily by

industry with equal or greater amounts. The national labs conduct the more

basic/applied research while the industrial labs focus on development. All

gained information is shared among member companies with a time lag assured

before general distribution. MITI's goal is to produce a knowledge base and

infrastructure for follow- on proprietary research by the now- experienced

industrial groups.

Among the 16 research institutes under AIST, the oldest is the

Electrotechnical Laboratory. ETL is also the largest national research

organization in Japan and has contributed to the advancement of science and

technology as well as the development of Japanese industry in the field of

electrical engineering and electronics for almost a century.

References

:

[1] JTECH (Japanese Technology Evaluation Program), JTEC Panel Report on Advanced Materials in Japan, Science Applications International Corp.,

LaJolla, CA, May (1986).

[2] J. Ronayne, "Science in Government," Edward Arnold Publishers, Ltc,

England (1984).

[3] Ceramics -Japan, High-Technology Ceramics in Japan, NMAB-418, National

Academy Press, Washington, DC (1984).

[4] NSF-Tokyo Office (National Science Foundation), "Japan's FY 1987 Science

and Technology Budget," Report Memorandum #144, Dec. 30 (1987).

79
APPENDIX E

Delegation Members

Lyle H. Schwartz

Director, Materials Science and Engineering Laborato

National Institute of Standards and Technology

Gaithersburg, MD 20899

John C . Angus

Department of Chemical Engineering

A. W. Smith Bldg.

Case Western Reserve University

Cleveland, OH 44106

Jerome J . Cuomo

IBM Research

Division 22, T. J. Watson Research Center

P.O. Box 218

Kitchawan Road

Yorktown Heights, NY 10598

Albert Feldman

National Institute of Standards and Technology

A329 Materials Building

Gaithersburg MD 20899

Jeffrey T. Glass

Materials Science and Engineering

Box 7907

North Carolina State University

Raleigh, NC 27695-7907

Sandor Holly

Rocketdyne Division

Rockwell International

6633 Canoga Avenue

Canoga Park, CA 91303

James W. Mitchell

AT&T Bell Laboratories

Materials Science and Engineering Research Division

1D239

600 Mountain Avenue

Murray Hill, NJ 07974

Ronald A. Rudder

Research Triangle Institute

Center for Semiconductor Research

P.O. Box 12194

Research Triangle Park, NC 27709-2194

80
Keith A. Snail

Code 6520

Naval Research Laboratory

Washington, DC 20375-5000

C. Martin Stickley

BDM International, Inc.

Present Address:

Center for Research in Electro-Optics and Lasers

University of Central Florida

12424 Research Parkway, Suite 400

Orlando, FL 32826

Michael A. Tamor

Ford Motor Company

Scientific Research Laboratories

Box 2053, Room S3006

Dearborn, MI 48121

Walter A. Yarbrough

266 Materials Research Laboratory

Pennsylvania State University

University Park, PA 16802

81
APPENDIX F

Biographies of Delegation Members

DR. LYLE H. SCHWARTZ, Chairman of the Visiting Delegation, is Director of the

Materials Science and Engineering Laboratory at the National Institute of

Standards and Technology. He is responsible for NIST's Materials Science and

Engineering Laboratory, which has more than 350 scientists, engineers,

technicians, and support personnel. The major research interests of MSEL are metals, polymers, ceramics, and com.posite materials. Dr. Schwartz is a graduate of Northwestern University, Evanston, Illinois, having received his

bachelor of science in engineering (1959) and doctorate (1964) in materials

science. Dr. Schwartz has published more than 80 technical papers in the area

of phase transitions in iron alloys, applications of Mossbauer spectroscopy,

x-ray and neutron diffraction, characterization of catalysts, and other

aspects of materials science. He is a co-author of two textbooks on x-ray

diffraction. He is a member of the Board of Directors of the National ^,

Materials Property Data Network, Inc., the Versailles Project on Advanced

Materials and Standards, Fellow and Chairman of Technical Divisions Board of

ASM International, and is a member of the American Crystallographic

Association, TMS , American Physical Society, University Materials Council

Advisory Board, and the Materials Research Society. He chaired the Panel on International Competition and Cooperation of the NRC study on Materials

Science and Engineering, and was recently appointed chairman of the

intergovernmental committee on materials, COMAT. .. -

PROFESSOR JOHN C. ANGUS is a Professor of Engineering at Case Western Reserve

University. He received his Ph.D. in Chemical Engineering from the University

of Michigan. He has over 106 publications in journals and conference

proceedings and holds eleven patents. He has served on the National Research

Council Committee on Superhard Materials and on the organizing committees of

several major conferences about diamond and diamond films. The research

Interests of Professor Angus include metastable diamond growth, applied

thermodynamics, electrochemical devices, crystal etching, etc. He was an early researcher in the deposition of diamond by chemical vapor deposition

processes from the gas phase. He discovered the importance of atomic hydrogen

for the deposition of diamond. Professor Angus has received numerous honors

and is a member of several professional societies including a Full Grade

Member of the American Institute of Chemical Engineers.

DR. JEROME J. CUOMO has been very active for many years in the field of

Materials Science and has published some 105 papers, 5 book chapters and is

co-editor of books on Ion Beam Processing and Plasma Processing. He has been

involved in the study of thin film preparation and properties and is

particularly involved in the study of sputtering, ion beam and plasma

processing. He is the author or co-author of some 60 patents issued or pending and of about 215 patent publications. He has been very active in the

American Vacuum Society as a member, Advisor to the Governors Scientific

Community Council for Puerto Rico, Advisor for the Materials Science

Departments of North Carolina State University, and Pennsylvania State

University and as the chairman of various committees of the American Vacuum

Society and the Materials Research Society. He has made important

contributions to the development of LaBg electron emitters and SijN^ as dielectric layers. He has pioneered work in selective chemical vapor

82
deposition, dendritic solar thermal absorbers, sputtered amorphous silicon,

amorphous magnetic bubble domain materials , ion beam modification and

synthesis of materials, enhanced plasma processes, plasma sprayed high T^. superconductors. He has been elected as a member of the National Research

Council for Superhard Materials 1988-1989. He has been elected as a member of

the Japanese and Untite States Workshop on Diamond Technology. He has also

held various management positions at the IBM Research Center and is presently

Manager -Materials Processing Laboratory. He is distinguished with the highest

patent level in the IBM Corporation.

DR. ALBERT FELDMAN, the organizer of this study, is Leader of the Optical

Materials Group at the National Institute of Standards and Technology. He

received his Ph.D. from the University of Chicago in the field of solid state

physics. He has worked for the past 28 years in the areas of solid state

physics and optical materials research. He has headed projects concerned with

self - focusing mechanisms in optical materials, basic properties of bulk

optical materials, and optical film research. Dr. Feldman has organized two

conferences sponsored by NIST dealing with the basic properties of optical

materials and he is cochairman of the Diamond Optics Conference Series

sponsored by the SPIE. He served as Program Committee Chairman of the Fourth

Annual SDIO/IST-ONR Diamond Technology Initiative Symposium and is on the

Local Arrangements Committee for the Second International Conference on the

New Diamond Science and Technology. He currently leads a project at NIST

concerned principally with diamond film deposition and characterization. Dr.

Feldman served on the National Research Council Committee on Superhard

Materials. In 1980, he was awarded the U.S. Department of Commerce Bronze

Medal

PROFESSOR JEFFREY T. GLASS is currently the Kobe Steel, Ltd. Assistant

Professor of Materials Science and Engineering at North Carolina State

University. He also serves as a consultant and Research and Development

Director for the Electronic Materials Center, Kobe Steel Research

Laboratories, U.S.A. In the past, he has worked as a materials engineer at

the Ballistic Research Laboratory, Aberdeen Proving Ground. He was an international advisor for the First International Conference on the New

Diamond Science and Technology (Tokyo, Japan) and Diamond Films '90

(Montreaux, Switzerland) and served on the program committees for the Fourth

Annual SDIO/IST-ONR Diamond Technology Initiative Symposium and the Second

International Conference on the New Diamond Science and Technology

(Washington, D. C). He was the Co-Chairman of the Fall 1989 Materials

Research Society symposium on Diamond, Boron Nitride, Silicon Carbide and

Related Wide Bandgap Semiconductors. He is also a short course instructor for

the Materials Research Society and is a member of Tau Beta Pi. Dr. Glass has

published over 30 papers and given over 35 professional presentations in the

United States, England, France and Japan, and is currently editing two books.

His education has been in the area of Materials Science and he currently

teaches Thermodynamics at NCSU. Research interests involve the growth and

characterization of thin films, especially diamond.

DR. SANDOR HOLLY has been Staff Scientist within the Advanced Programs

Department of the Rocketdyne Division of Rockwell International for over 14

years. He has extensive background in laser system analysis, conceptual

design and design implementation of electro-optical and control systems.

83
Previously he was Manager with a variety of responsibilities in Experimental

Optics, Electro Optics and Alignment Systems. His formal education was in

Electrical Engineering (M.Sc. from the Massachusetts Institute of Technology)

and in Physics (Ph.D. from Harvard University). He has 30 years of experience

in Electro Optics, Instrumentation, Lasers, Diagnostic Techniques, Metrology

and solving difficult experimental problems. He has received 16 U.S. and

several foreign patents. A variety of academic and industrial experiences

include Member of the Faculty in the Physics Department at University of

Maryland to Technical Director of a small company building Laser

Instrumentation to Staff Scientist at Rockwell. His technical backgrounds are

in Electromagnetic, Optics, Lasers (received the first U.S. patent issued on

Free Electron Lasers), Instrumentation, Sensors, Control Systems, and New

Materials. He has organized several conferences. He is one of the organizers

and one of the cochairmen of the Diamond Optics Conferences (in its fourth

year this July) and coorganizer of an International Conference in Hungary on

"Computer Aided Laser Metrology" (September, 1990).

DR. JAMES W. MITCHELL heads the Analytical Chemistry Research Department of

Bell Laboratories at Murray Hill, New Jersey. After receiving a B.S. degree

in chemistry from the Agricultural and Technical State University of North

Carolina at Greensboro (1965) , he entered Iowa State University at Ames and

earned the Ph.D degree in analytical chemistry in 1970. He joined AT&T Bell

Laboratories in March of that year as a Member of Technical Staff, accepted

the position of Supeirvisor of the Inorganic Analysis Group in 1972, and was promoted to Head of the Department in 1975. In 1985 he was made an AT&T Bell

Laboratories Research Fellow for pioneering work in the creation and

application of novel techniques for the analysis of chemical elements and

components at unprecedentedly low levels of concentration. Dr. Mitchell's

work includes using nuclear radiation and spectroscopy to develop high

accuracy methods for ultratrace analysis, development of methods for the

ultrapurification of analytical reagents and research chemicals, and

exploiting microwave discharges and plasmas for analysis and synthesis of

materials. He has lectured internationally on these subjects, co-authored a book on "Contamination Control in Trace Analysis," completed over 60

scientific papers for publication, and invented novel instruments and

processes. He has served as a member of the Editorial Advisory Boards of

three international analytical chemistry journals. Dr. Mitchell has received

several awards for his work: the Pharmacia Industrial Analytical Chemistry

Award in 1978, The Percy L. Julian Research Award in 1981 and the IR-lOO Award

in 1982. In 1989 he received a second IR-100 award and was inducted into the

National Academy of Engineering.

DR. RONALD A. RUDDER is a research engineer in the Center for Semiconductor

Research at Research Triangle Institute, Research Triangle Park, NC. He

received a B.S. degree in mathematics and physics from Lynchburg College and a

PhD. degree in physics from North Carolina State University. He is

responsible for the development of epitaxial chemical vapor deposition

techniques both with and without plasma-activation. His research interests

include epitaxial growths of diamond, silicon, germanium, gallium nitride, and

alloys such as SiGe and dilute C, SiC alloys.

DR. KEITH A. SNAIL received a B. S. in physics in 1978 (summa cum laude) from

the Honors Tutorial College at Ohio University. He went on to study

nonimaging optics and solar energy under Roland Winston at the University of

84
Chicago and received his Ph.D. in physics in 1983. He then began work as a research physicist at the Naval Research Laboratory's (NRL) Optical Sciences

Division. Dr. Snail's research at NRL has focused on three areas: (1) the

combustion and CVD synthesis of diamond, 2) the optical characterization of

diamond and other optical materials, and 3) the development of high accuracy

diffuse reflectometers . Dr. Snail has received 3 patents and is the author of over 20 publications.

DR. C. MARTIN STICKLEY received his BSEE from the University of Cincinnati,

the MSEE from MIT, and the Ph.D from Northeastern University. His early

research work was in the dynamics of optically-pumped crystalline lasers and

in laser- induced damage to laser materials. He became the Director for

Materials Sciences of the Advanced Research Projects Agency where he initiated

a nvimber of R&D programs to develop new optical and IR materials for use with

lasers. He later became the Director of the Inertial Confinement Fusion

Program at the Department of Energy where he initiated efforts to build the

world's largest laser, NOVA, at the Lawrence Livermore National Laboratory.

Subsequently, he joined BDM International, Inc., a professional and technical

services firm which conducts research and development for clients. At BDM, he

developed an Advanced Technology Group which conducts research in sensors,

photonics, neural networks, applications of advanced computing architectures,

intelligent controls for materials processing, and other subjects. Dr.

Stickley is now Assistant Director and Professor of Electrical Engineering at

the Center for Research in Electrooptics and Lasers at the University of

Central Florida. He is a Fellow of the Institute of Electrical and Electronic

Engineers and serves as an unofficial advisor to the Materials Sciences

Division of the Defense Advanced Research Projects Agency.

DR. MICHAEL A. TAMOR earned his B.S. in Physics from the University of

California, Los Angeles and his M.S. and PhD. in physics from the University

of Illinois at Urbana- Champaign (1982) . His thesis research involved a systematic study of the transport properties of excitons and electron-hole

droplets in ultrapure silicon and germanium. Upon completion of his

dissertation. Dr. Tamor joined the Research Staff of Ford Motor Company where

he is now a principal research scientist in the Physics Department. While at

Ford, he has worked in the areas of optical and electronic properties of

semiconductor alloys, transport in highly disordered materials and electronics

for high temperature operation. His current research is in the area of the

formation, structure and applications of both diamond and diamondlike hard

carbon materials

PROFESSOR WALTER A. YARBROUGH has spent most of his career in industrial

product and process development, first with Celanese Fibers Co. and

subsequently with the Norton Co. of Worcester Massachusetts. He held several

positions with both organizations, the most recent ones being Manager of

Product Development and Senior Research Associate with the Norton Co. He

returned to the academic community when offered the opportunity to work and

study at the Materials Research Laboratory of the Pennsylvania State

University where he completed a Ph.D in Solid State Science under Rustum Roy

and where he is presently Assistant Professor of Solid State Science. He

holds patents on industrial products in the fields of sol -gel chemistry and

composite materials and is a consultant to research and business

organizations. He has been an invited speaker and lecturer at many

institutions, national and international meetings on sol-gel materials, the

85
preparation of hard coatings, and low pressure diamond synthesis. Presently

he supervises much of the current research in the deposition of diamond, boron

nitride and related materials through the Diamond and Related Materials

Consortium of The Pennsylvania State University. His research interests are

in materials synthesis and his published and presented work includes the

preparation of ceramics by chemical methods (e.g., "sol-gel"), the control of

microstructure by seeding, the preparation of nanocomposites , the

thermodynamics of materials synthesis, and presently focuses on the chemical

vapor deposition of diamond and cubic boron nitride.

86
APPENDIX G

Itinerary

DIAMOND TECHNOLOGY IN JAPAN -- Itinerary, Revision of May 23, 1990

(number of visitors in parenthesis)- Name represents site report coordinator

May 26 - 27 Travel to Japan

Mon May 28 1:30pm JRDG (1) L. Schwartz

Tues May 29 Tokyo am 10:00 Team A STA (4) Stickley

10:30 Team B Asahi Diamond (4)

11:00 Team C Fujitsu (4)

pm

1:30 MITI (4) L. Schwartz

Asahi Diamond Feldman

to 3:00 Snail

Wed May 30 Tokyo am 9:30 Team A Showa Denko K.K. (4)

Stickley

9:00 Team B Mitsubishi Metals (4)

Yarbrough

9:30 Team C Idemitsu (4) Holly

pm

1:30 Aoyama Gakuin U. (4) Cuomo

1:30 Nippon Institute of Tech. (4)

Tamor

2:00 Seiko (4) Angus

Thurs May 31 Travel to Tskuba am 10:30 Full team NIRIM (12)

pm return to Tokyo

NIRIM Mitchell

Fri June 1 Tokyo am

9:00 Team A' Tokyo Inst, of Tech.

Snail (4)

9:00 Team B' Toshiba Tungaloy (4)

Yarbrough

9:15 Team C' Semiconductor En. Lab

(4) Rudder

pm

1:30-4:00 NEC Fundamental Res. Lab.

(4) Mitchell

Sat June 2 Travel to Osaka

WEEKEND

Sun June 3 Osaka

Mon June 4 Osaka am 9:00 Full team Osaka University (11)

Angus

pm

1:00 Sumitomo Electric (11)

(Itami Research Center) Rudder

Tues June 5 Osaka am Full team (A"+B")

9:00 Team B" Matsushita Electric (3)

Tamor

pm

1:30 Kobe Steel (11) Glass

(3 may arrive late)

Wed June 6 Osaka am Prepare draft report

pm

Return to U.S.

87
Visiting Teams

Team A

Schwartz

Glass

Cuomo

Stickley

Team B

Feldman

Yarbrough

Tamor

Rudder

Team

Schwartz

Glass

Stickley

Snail

Team B

' Feldman

Yarbrough

Tamor

Mitchell

Team A

" Glass

Mitchell

Stickley

Snail

Feldman

Yarbrough

Holly

Rudder

Team C

Snail

Angus

Mitchell

Holly

Team C

' Angus

Cuomo

Holly

Rudder

Team B

" Angus

Cuomo

Tamor

88
APPENDIX H

List of Companies, Universities and Government Agencies Visited

Aoyama Gakuin University

Professor Tadao Inuzuka

6- 16-1 Chitosedai

Setagaya-ku, Tokyo 157, Japan '

Asahi Diamond Industrial Co., Ltd

Dr. Kozuo 0-oka

Director and Manager of R&D

7- 2, Kouj imachi 5-chome

Chiyoda-ku, Tokyo 102 Japan

Fuj itsu Inc

Dr. Takahiko Misugi

Managing Director

Fujitsu Laboratories Ltd.

10-1 Morisato-Wakamiya,

Atsugi 243-01 Japan

Idemitsu Petrochemical Co., Ltd.

Dr. K. Ito

Manager

Planning of High-Tec Materials

Planning and Development Department

3-1-1 Marunouchi, Chiyoda-ku

Tokyo 100 Japan

Kobe Steel Corp. (Kobelco)

Dr. Masami Konishi

Deputy General Manager

Electronics Research Laboratory \-

5-5 Takatsukadai 1-chome Nishiku

Kobe, Hyogo 673-02 Japan

Matsushita Electric Industrial Co. Ltd.

Dr. Tsuneharu Nitta

Director

Central Research Laboratories

3-15 Yagumo-Nakamachi , Moriguchi

Osaka 570, Japan

Ministry of International Trade and Industry (MITI)

Makoto Sonai

Director

Fine Ceramics Office

1-3-1 Kasuniigaseki

Chiyoda-ku, Tokyo 100 Japan

89
Mitsubishi Metal Corporation

Dr. Akihiko Nagasaka

Director of Research

1-297 Kitabukuro-cho

Omiya, Saitama 330 Japan

National Institute for Research in Inorganic Materials (NIRIM)

Dr. Yoichiro Sato

Diamond Group Leader

1- 1 Namiki, Tsukuba

Ibaraki 305 Japan

NEC Corporation

Dr. Hisatsune Watanabe

General Manager

Fundamental Research Laboratories

34, Miyukigaoka

Tsukaba, Ibaraki 305 Japan

Nippon Institute of Technology

Professor Masao Murakawa

Mechanical Engineering Institute of Technology

Miyashiromachi

Saitama 345 Japan

Osaka University

Professor Akio Hiraki

Department of Electrical Engineering

Suita-shi, Osaka 565 Japan

Research and Development Corporation of Japan (JRDC)

Dr. Masaru Goto

5-2 Nagata-cho 2-chome

Chiyoda-ku, Tokyo 100 Japan

Science and Technology Agency (STA)

Takayuki Shirao

Director

Office of Materials Science and Technology

Bureau of Research and Development

2- 2-1 Kasumigaseki

Chiyoda-ku, Tokyo Japan

Seiko Instruments

Ryoichiro Sakami

Director

Technology & Project Administration Department

563, Shinden Takatsuka, Matsudo-shi

Chiba 271 Japan

90
Semiconductor Energy Laboratory Co., Ltd.

Dr. Shumpei Yamazaki

President

398 Hase Atsugi-shi, Kanagawa-ken

,

243 Japan

Showa Denko K.K. Annex

Dr. Junichi Sato

Chief Staff Manager

Ceramics Division

1-13-9 Shibadaimon, Minato-ku

Tokyo, 105 Japan

Sumitomo Electric Itami Research Center

Dr. Akio Hara, Director

1- 1 Koyakita, 1-chome

Itami-shi, Hyogo, 664 Japan

Tokyo Institute of Technology

Professor Osamu Fukunaga

Department of Inorganic Materials

2- 12-1, 0-okayama

Meguro-ku, Tokyo 152 Japan

Tokyo Institute of Technology

Professor Masanori Yoshikawa

Department of Mechanical Engineering

2-12-1, 0-okayama

Meguro-ku, Tokyo 152 Japan

Toshiba Tungaloy Inc

.

Dr. Tamotsu Fukatsu

Vice President and Director

General Manager of Technical Research Division

Toshiba Tungaloy Inc.

1-7, Tsukagoshi, Saiwai-ku

Kawasaki, 210 Japan

91
APPENDIX I Alphabetical Listing of Abbreviations

Al aluminum

Ar argon

As arsenic

Au gold

B boron, billion

BN boron nitride

B2Hg diborane

C carbon

cBN cubic boron nitride

CH^ me thane

CI chlorine

CO carbon monoxide

Co cobalt

CO2 carbon dioxide

CVD chemical vapor deposition

DC direct current

DLC diamondlike carbon

EACVD electron assisted chemical vapor deposition

ECR electron cyclotron resonance

ERATO Exploratory Research for Advanced Technology

ESCA electron spectroscopy for chemical analysis

H, H2 hydrogen

HFCVD hot filament chemical vapor deposition

HPHT high pressure/high temperature

JNDF Japan New Diamond Forum

JRDC Japan Research and Development Corporation

JTECH Japanese Technology Evaluation Program (U.S.)

KW kilowatt

M million

MESFET metal semiconductor field effect transistor

MITI Ministry of Internation Trade and Industry

MOMBUSHO Ministry of Education, Science and Culture

MSE materials science and engineering

Nd:Yag yttrium aluminum garnet doped with neodymium

NIRIM National Institute for Research in Inorganic Materials

NIT Nippon Institute of Technology

Ni nickel

NMR nuclear magnetic resonance

NRIM National Research Institute for Metals

NSF National Science Foundation (U.S.)

0, O2 oxygen

P phosphorus

R&D research and development

RHEED reflection high energy electron diffraction

RF radio frequency

S sulfur

S&T science and technology

SD Showa Denko K. K.

Se selenium

SEL Semiconductor Energy Laboratory

92
SENTAXY Selective nucleation based epitaxy. As used here - nucleation at

selected sites

Si silicon

SiC silicon carbide

SIMS secondary ion mass spectroscopy

STA Science and Technology Agency

TAB tape automated bonding

Ti titanium

TIT Tokyo Institute of Technology

W tungsten

wc tungsten carbide

WC-Co tungsten carbide with a cobalt binder

UHV ultrahigh vacuum

VLSI very large scale integrated circuits

93

NIST-114A

(REV. 3-89) U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

BIBLIOGRAPHIC DATA SHEET

1 . PUBLICATION OR REPORT NUMBER

NIST/SP-807

2. PERFORMING ORGANIZATION REPORT NUMBER

3. PUBUCATION DATE January 1991

4. TITLE AND SUBTITLE

U.S. Assessment of the New Diamond Technology in Japan

5. AUTHOR(S) Albert Feldman and Lyle H. Schwartz

6. PERFORMING ORGANIZATION (IF JOINT OR OTHER THAN HIST, SEE INSTRUCTIONS)

U.S. DEPARTMENT OF COMMERCE

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

GAITHERSBURQ, MD 20899

7. CONTRACT/GRANT NUMBER

8. TYPE OF REPORT AND PERIOD COVERED

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (STREET, CITY, STATE, ZIP)

Same as item #6

10. SUPPLEMENTARY NOTES

DOCUMENT DESCRIBES A COMPUTER PROGRAM; SF-185, FIPS SOFTWARE SUMMARY, IS ATTACHED.

11. ABSTRACT (A 200-WORD OR LESS FACTUAL SUMMARY OF MOST SIGNIFICANT INFORMATION. IF DOCUMENT INCLUDES A SIGNIFICANT BIBUOGRAPHY OR

UTERATURE SURVEY, MENTION IT HERE.)

This assessment of Japanese diamond technology was undertaken at the request

of the joint committees for implementation of the 1988 United States -Japan

Agreement on Cooperation in Research and Development in Science and Technology

under the auspices of the Committee on Materials, Office of Science and

Technology Policy. The purposes of the study were to assess the level of

scientific activity, areas of intended commercialization, progress in

commercialization, the role of the Japanese government in assisting industry

to exploit the new diamond technology, and the relative positions of Japan and

the U.S. in all aspects of synthesized diamond technology. Japanese efforts were chosen for assessment because Japan is the apparent world leader in the

drive for commercialization of this technology. The principal focus of the

study was diamond produced by chemical vapor deposition, with a peripheral

investigation of cubic boron nitride and diamond- like carbon. Based on this

assessment, a set of Conclusions and Recommendations is presented. This

assessment is based on site visits in Japan between May 28 and June 5, 1990.

12. KEY WORDS (6 TO 12 ENTRIES; ALPHABETICAL ORDER; CAPITALIZE ONLY PROPER NAMES; AND SEPARATE KEY WORDS BY SEMICOLONS)

abrasives; adhesion; BN; bonding; boron nitride; chemical vapor deposition; commercialization;

cubic boron nitride; cutting tools; CVD; diamond; diamond films; diamond technology; diamondlike carbon; doping; electronics, epitaxial growth; epitaxy; hard materials; heat conduction; mana ement'

^^'^^'^^^ tools; nucleation; optics; physical properties; polishing; thermal

13. AVAILABIUTY UNUNITED

FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE TO NATIONAL TECHNICAL INFORMATION SERVICE (NTIS). X

X

ORDER FROM SUPERINTENDENT OF DOCUMENTS, U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON, DC 20402. ORDER FROM NATIONAL TECHNICAL INFORMATION SERVICE (NTIS), SPRINGFIELD. VA 22161.

14. NUMBER OF PRINTED PAGES

96

IS. PRICE

ELECTRONIC FORM

*U.S.G.P.O: 1991 -281-557:40001

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