National Institute of 

Standards and Technology

Technology Administration

U.S. Department of 

Commerce

NISTIR 6614

January 2002

Electronics and Electrical 

Engineering Laboratory

Electromagnetic

Technology

Division

Programs, Activities, and 

Accomplishments
The Electronics and Electrical

Engineering Laboratory

Through its technical laboratory research programs, the

Electronics and Electrical Engineering Laboratory (EEEL)

supports the U.S. electronics industry, its suppliers, and its

customers by providing measurement technology needed to

maintain and improve their competitive position. EEEL also

provides support to the Federal government as needed to

improve efficiency in technical operations, and cooperates

with academia in the development and use of measurement

methods and scientific data.

EEEL consists of six programmatic divisions and two matrixmanaged offices:

Electricity Division

Semiconductor Electronics Division

Radio-Frequency Technology Division

Electromagnetic Technology Division

Optoelectronics Division

Magnetic Technology Division

Office of Microelectronics Programs

Office of Law Enforcement Standards

This document describes the technical programs of the

Electromagnetic Technology Division. Similar documents

describing the other Divisions and Offices are available.

Contact NIST/EEEL, 100 Bureau Drive, MS 8100,

Gaithersburg, MD 20899-8100, Telephone: (301) 975-2220,

On the Web: www.eeel.nist.gov
Electronics and Electrical

Engineering Laboratory

Electromagnetic

Technology

Division

Programs, Activities, and

Accomplishments

NISTIR 6614

January 2002

U.S. DEPARTMENT OF COMMERCE

Donald L. Evans, Secretary

Technology Administration

Phillip J. Bond, Under Secretary of Commerce for Technology

National Institute of Standards and Technology

Arden L. Bement, Jr., Director

ME

UNITED STATES OF AMERICA

DEPARTMENT OF COM

RCE

 Electromagnetic Technology Division iii

Contents

Welcome ......................................................................................................................... iv

Josephson Array Technology ............................................................................................1

Nanoscale Cryoelectronics .................................................................................................6

Terahertz Technology......................................................................................................15

High Tc Electronics ..........................................................................................................19

Nanoscale Fabrication .....................................................................................................24

Appendix A: Experimental Systems and Instruments .........................................................25

Appendix B: Postdoctoral Opportunities............................................................................26

Appendix C: Awards and Recognition ...............................................................................27

Appendix D: Electromagnetic Technology Division Staff.....................................................30
iv Electronics and Electrical Engineering Laboratory

Welcome

The roughly forty staff and guest scientists in the Electromagnetic Technology Division and I

take great pride in bringing you this brief report on recent progress of our Division. We have

a long history of inventing and disseminating new standards and measurement technology.

We focus on exceptional standards and measurement methods using remarkable quantum

effects and low noise available only at temperatures close to absolute zero or 0 K (–460 oF).

This publication describes some of our recent successes.

It has always been our goal to provide U.S. industry with the best metrology in the world.

We began about thirty years ago to bring the unique capabilities of cryogenic electronic

technology to bear on metrology, the science of measurement. In many cases our technology

enables measurements that are otherwise impossible. We developed what has become the

world’s practical standard of voltage, based on integrated circuits containing tens of thousands of superconducting Josephson junctions made in our own fabrication facility. We demonstrated the first capacitance standard based on counting of single electrons. For materials

analysis, we perfected an X-ray spectrometer that combines the best features of two types of

existing detectors and promises to be critical in defect analysis of future semiconductor devices. We have also improved our cleanroom facilities, which are critical to all of our efforts

and enable us to produce microfabricated structures smaller than 100 nanometers.

We have a long tradition of excellence dating back to the formation of our organization in

1969. Our world-leading work has resulted in many prestigious awards to our staff, some of

which are listed in Appendix C.

Whether you are our customer and use the results of our efforts, or are simply interested in

the remarkable progress our technology brings to measurements, we hope you will find this

report exciting. You will find descriptions of our recent work, lists of our publications, and

descriptions of our postdoctoral research opportunities. For the most up-to-date information,

please visit our Web site, http://emtech.boulder.nist.gov. Our website also contains a

searchable bibliography of all of our publications.

Thank you for your interest in NIST’s Electromagnetic Technology Division.

Richard E. Harris

Division Chief

Electromagnetic Technology Division

National Institute of Standards and Technology

325 Broadway

Boulder, Colorado 80305-3328

(303) 497-3678

http://emtech.boulder.nist.gov
 Electromagnetic Technology Division 1

Josephson Array Technology

Goals

To develop superconducting electronic circuit

and system technology for fundamental, quantum-based DC and AC voltage standard systems;

to provide improved standards for fundamental

metrology; and to support U.S. industry’s test and

measurement applications.

Clark Hamilton operating one of the 10 V conventional Josephson voltage standard systems

developed at NIST and used throughout the

world for calibration of Zener voltage references.

Customer Needs

The demands of modern technology for accurate

voltage calibrations have gradually exceeded the

capability of classical artifact standards. To meet

current needs, an international agreement signed

in 1990 redefined the practical volt in terms of

the voltage generated by a superconductive

integrated circuit developed at NIST and the

Physikalisch-Technische Bundesanstalt in Germany. This circuit contains thousands of superconducting Josephson junctions, all connected in

a series array and biased at a microwave frequency. The voltage developed by each junction

depends only on the frequency and a fundamental

physical constant; thus, the circuit never needs to

be calibrated. This allows any standards or commercial laboratory to generate highly accurate

voltages without the need to calibrate an artifact

standard. This advance has improved the uniformity of voltage measurements around the

world by about a hundredfold. These systems are

rapidly becoming essential for meeting legal and

accreditation requirements in commercial, governmental, and military activities.

The U.S. electronics instrumentation industry

maintains its world position through the development and deployment of increasingly accurate,

flexible, easier-to-use instruments. Providing

U.S. industry with quantum voltage standard

systems gives these customers, with appropriate

oversight from the NIST Electricity Division,

immediate realization of the highest possible inhouse accuracy. These customers also benefit

dramatically by eliminating their dependence on

less accurate reference standards that require

frequent calibration.

We also support the standards community by

developing voltage standard systems with new

capabilities, including lower cost, increased

functionality, and ease of use. Other customers

are the superconductive electronics community

and the U.S. military, which we support through

development of novel superconductive circuits

and high-performance systems, and by providing

technical expertise.

Over the past 20 years, this project has developed

superconductive Josephson junction array technology for quantum voltage standard systems.

Groundbreaking work at NIST led to commercialization of the first practical dc Josephson

voltage standard system. Recent improvements in

system design and operation have led to a traveling Josephson voltage standard system that is

compact, of low cost, and transportable for calibration of Zener reference standards. The technology for this conventional Josephson voltage

standard system has been completely transferred

to the private sector, where systems are produced

and supported by a number of small companies.

A 1 centimeter × 1 centimeter superconductive

integrated circuit with 32 768 SNS Josephson

junctions for the 1 volt programmable voltage

standard.

A few years ago, we developed a novel superconductor-normal metal-superconductor (SNS)

Technical Contact:

Sam Benz

Staff-Years (FY 2001):

3 NIST staff

1.25 Other staff

The voltage pulse

developed by

each junction

depends on

fundamental

physical constants

and never needs

to be calibrated.
 2 Electronics and Electrical Engineering Laboratory

junction technology that adds the features of

stability and programmability to the accuracy of

conventional Josephson voltage standards. Programmable Josephson voltage standard systems

based on these junctions have been delivered to,

and installed in, a number of metrology experiments – namely the Watt-balance experiments at

NIST and Switzerland’s Federal Office of Metrology (OFMET) and the metrology triangle

experiment at France’s Central Laboratory for

Electrical Industry (LCIE), where these features

should reduce the uncertainty of the experimental

measurements.

Charles Burroughs with the 1 volt programmable

voltage standard system showing (left to right)

the low thermal probe, the microwave and highspeed bias electronics, and the computer control.

The NIST Electricity Division (811) is interested

in improving the internal efficiency of its maintenance and dissemination of the volt through the

development and deployment of an improved

one-volt programmable voltage standard. This

year we collaborated with Electricity Division

staff to develop a Josephson voltage standard to

be used directly in the customer calibration chain.

This system has been completed and delivered to

the calibration lab in Gaithersburg, MD.

Technical Strategy

Our present primary goal is to develop the

world’s first quantum-mechanically accurate

voltage source for both ac and dc metrology. The

device is effectively a digital-to-analog converter

capable of synthesizing arbitrary waveforms

using the perfectly quantized pulses of Josephson

junctions. The concept for this new device was

co-invented by NIST and Northrop-Grumman

researchers in 1996. Present ac voltage calibrations are done using ac-dc thermal voltage converters. A quantum-based ac source would provide an entirely new instrument and methodology

for ac metrology. Its use as a stable generator of

accurate arbitrary waveforms would also be

useful for calibration of other scientific instruments, such as ac voltmeters, spectrum analyzers,

amplifiers, and filters. The major challenge of

this technology is to achieve practical output

voltages by developing improved broadband

circuits and novel submicrometer junctions.

We will develop an ac voltage source with an

output voltage of 1 volt.

Paul Dresselhaus demonstrates a waveform

synthesized with the Josephson arbitrary waveform generator.

The concept of an arbitrary-waveform generator

with quantum mechanical accuracy has enabled

the possibility of making a quantum-based thermometer. The quantum-based waveform generator can be used to synthesize an equivalent noise

voltage with a known, calculable noise spectrum.

This quantized noise source can be used to calibrate the correlator measurement electronics of a

Johnson noise thermometry system. In collaboration with the Chemical Science and Technology

Laboratory’s Process Measurements Division

(836), we have begun development of this new

quantum-based electrical thermometer.

We will develop a quantized voltage noise source

for calibration of a Johnson noise thermometer.

Accomplishments

 NIST operates 1 V Josephson chip on a

cryocooler — In collaboration with Sandia National Laboratories and NASA, NIST researchers

have successfully operated a 1 V conventional

voltage standard chip on a 4 K cryocooler. Guest

researcher Clark Hamilton designed a cryopackage that was compatible with the Josephson

voltage standard. The cryostat was built by Cryo

Industries of America, Inc. Dr. Hamilton installed

75 GHz waveguide and dc wiring for biasing the

superconducting chip. Hypres, Inc. provided a 1

V array chip that was mounted on a copper block

Groundbreaking

work at NIST led to

commercialization

of the first practical

DC Josephson

voltage standard

system.

Our present

primary goal is to

develop the world’s

first quantum

mechanically

accurate voltage

source for both AC

and DC metrology.

We provide

systems and

support to NIST

and other national

metrology

laboratories for

Josephson voltage

standard systems.
 Electromagnetic Technology Division 3

for efficient cooling. All the components were

assembled and cooled to 4 K using Leybold’s

Coolpower 4.2 LAB cryocooler, which includes a

two-stage Gifford-McMahon cryocooler and a

CTI 8200 2.1 kW compressor. The cryocooler

provides 0.25 W of cooling power at 4.2 K. The

chip was successfully cooled to 4 K, where the

Josephson junctions produced the appropriate

zero-crossing constant-voltage steps that are

necessary for conventional voltage standard

operation. The cryocooler and cryopackage are in

use at Sandia National Laboratories.

 NIST demonstrates remote operation of 10

Volt Josephson voltage standard system — At the

June 2001 Combined Calibration Group (CCG)

meeting, Charles Burroughs demonstrated the

new Windows version of the control software for

the conventional 10 Volt Josephson Voltage

Standard (JVS) system. This software is the first

to provide remote operating capability of JVS

systems. A laptop computer with a modem connection in a conference room in Gaithersburg was

used to dial-up the 10 V JVS in the Josephson

Array Technology Lab in Boulder. Complete

remote control of the system was demonstrated

by performing a number of calibrations. The new

software will replace older DOS-based software,

making the system compatible with current

computer hardware and software. Remote operation will reduce operating costs of JVS systems

by allowing an operator (or repair expert) to

monitor, control, and diagnose JVS systems from

any location. Additional enhancements will allow

JVS operators to collect statistics and perform all

the capabilities of the earlier DOS-based software. VMetrix, LLC (Clark Hamilton) and Universal CADD (Rich Jones) have been contracted

to do most of the programming.

 Uniform Ti-barrier Josephson junction arrays

for ac Josephson voltage standard — We have

made the first uniform arrays of Josephson junctions using titanium as a junction barrier material.

We have focused on using Ti because it can be

reactive ion etched with the superconducting Nb

electrodes. Paul Dresselhaus and Jelle Plantenberg have made a considerable effort experimenting with different etch chemistries to improve the etch anisotropy for etching pentalayer

Nb-Ti-Nb-Ti-Nb junction stacks. For example,

the figure below shows both isotropic (right, top)

and anisotropic (right, bottom) etch processes for

a 2-junction pentalayer. The stepped pyramid

(right, top) is undesirable compared to the nearly

vertical walls (right, bottom) for the anisotropic

etch. Two vertically stacked junctions fabricated

with this process should have nearly identical

areas that very closely match the dimensions of

the photoresist. The closely matched areas of the

two junctions are essential to ensure that their

electrical characteristics are similar.

Nb-Ti-Nb-Ti-Nb pentalayer with photoresist on

top, etched with standard SF6 process resulting

in an undesirable stepped pyramid profile. The

pentalayer thicknesses from bottom to top are

250 nm, 40 nm, 140 nm, 40 nm, and 140 nm.

Nb-Ti-Nb-Ti-Nb pentalayer with photoresist on

top, etched with SF6 + O2 process yielding a

desirable nearly vertical sidewall. Same thicknesses as above.

Using this new process we fabricated arrays of

single (unstacked) Nb-Ti-Nb junctions in microwave circuits designed for arbitrary waveform

synthesis. These junction arrays are embedded in

microwave circuits that are used to evaluate the

junction uniformity. We successfully generated

constant-voltage steps in 1000- and 4100-

junction series arrays. This result is encouraging

because it demonstrates that the correct voltage is

generated over a significant current range for a

broad range of frequencies for this large 4100-

junction array. This indicates good junction

The concept of an

arbitrary voltage

waveform generator

with quantummechanical accuracy

has enabled the possibility of making an

electronically based

thermometer.

Improved operating

margins and a new

circuit design have

enabled us to perform

the first ac metrology

measurements of the

Josephson arbitrarywaveform synthesizer.
 4 Electronics and Electrical Engineering Laboratory

uniformity as well as good microwave uniformity

for the Ti normal-metal barrier. This result allowed us to attempt a stacked 2-junction pentalayer (described below).

 First quantum voltage steps demonstrated in

an array of stacked Josephson junctions — We

have measured the first constant voltage steps in

stacked Ti-barrier Josephson junctions. This is a

significant milestone toward creating lumped

arrays of Josephson junctions for ac voltage

standards. In order to achieve higher output

voltage for future standards, all of the junctions

must be tightly packed into a size smaller than

one-quarter wavelength of the microwave drive

frequency. This lumped-array design ensures

that all the junctions see nearly the same microwave power, and it is more efficient than distributed arrays because all of the microwave power

is used to drive junctions, not dissipated in a

termination resistor. For ac and dc programmable voltage standards, lumped arrays will enable

increased output voltage, increased bandwidth,

increased operating margins, and operations at

lower-power.

One thousand double-junction stacks, for a total

of 2000 series-connected junctions, were fabricated for the first time. The 40 nm titanium

barriers are separated by only 50 nm of niobium.

When a 16 GHz microwave bias is applied, a

constant voltage step is measured at the expected

quantized value of 66.17 mV. The voltage of the

step is constant over a 3.5 mA current range,

which is more than sufficient for operation as a

programmable voltage standard array. This

observation of constant voltage steps demonstrates that the stacked junctions are sufficiently

uniform for application in voltage standard circuits. For each increase in the number of junctions per stack, we expect to see an improvement

in operating margins. Adding a third and fourth

junction to each stack will be the next step toward our goal of fabricating and observing steps

in 50-junction stacks in order to create a lumped

array 2 mm long with a 50 ohm impedance.

Sam Benz optimizes the operating margins for

the Josephson arbitrary-waveform synthesizer.

 Broadband operation of Josephson synthesizer circuits — Progress has been made toward

the development of improved circuits for the

Josephson arbitrary-waveform synthesizer. A

number of filter designs were found that allow

operation at higher frequency and wider

broadband compared to previous designs. This

has led to a circuit with the largest dc output

voltage per junction to date using two seriescoupled 3750-junction arrays (for a total of 7500

junctions). Constant voltage steps were measured

on this circuit across a broad range of frequencies

from 3 to 18 GHz. Also as a result of the improved filters, another circuit with 1000 junctions

was driven at a bit-stream data rate by more than

a factor of two higher than any previous Josephson array circuit; the bit-stream data rate was

successfully increased from 5 gigabits per second

to 12 gigabits per second (the maximum data rate

of the HP bit-stream generator) while maintaining operating margins for a kilohertz synthesized

sine wave. This result gives us confidence that

we will be able to fabricate circuits that can be

used with the fixed-speed low-cost bit stream

generator at 10 gigabits per second that is currently under construction.

 Constant voltage steps in Josephson junction

series arrays at 10 K — NIST is collaborating

with Dr. Shoji at Japan’s Electrotechnical Institute (ETL), [which has recently become part of

the National Institute of Advanced Industrial

Science and Technology (AIST)] to develop a

higher-temperature programmable voltage standard, so that this system can operate with an

economical cryocooler. We have provided fabrication development advice, circuit designs and

circuit testing. After considerable improvements
 Electromagnetic Technology Division 5

in their fabrication process over the last two

years, including the addition of 2 planarization

steps and the addition of NbN wiring, Dr. Shoji’s

group has made the first all-NbN arrays with

useful operating margins. Arrays of 4096 junctions have sufficient uniformity at an operating

temperature of 10 K to generate constant voltage

steps. An array circuit was designed with different numbers of junctions in a binary sequence to

demonstrate operation as a programmable dc

standard. The data show that each segment has a

common current bias range of 3 mA for the n=1

step. The total array voltage when all segments

are on the n=1 step is 135.5 mV. This circuit can

be used as a 10 K programmable standard operating over a range of ±135 mV. The uniformity is

also good enough to begin designing circuits with

33,000 (unstacked) junctions for 10 K programmable voltage standard circuits. We hope to

continue this collaboration with AIST and begin

stacking the junctions for lumped arrays.

Collaborations

 We are collaborating with Dr. Shoji and Dr.

Yamamori at Japan’s AIST to develop cryocooler-compatible Josephson junctions for programmable voltage standards. The latest results

are described above in the accomplishments.

 We are collaborating with Ian Robinson of

the National Physical Laboratory (NPL), England, to provide a programmable 1 V probe and

chip for their Watt-balance experiment. NPL will

purchase the probe from NIST and construct their

own bias electronics and computer control.

 We are collaborating with Northrop-Grumman on the development of a pulse-quantized

arbitrary waveform generator for radar

applications. This application uses the same

pulse-quantized AC synthesis techniques as the

NIST metrology application except at radar

frequencies. We have designed and fabricated

SNS junction circuits using Northrop-Grumman

designs and demonstrated multiple-tone waveforms at megahertz frequencies.

Recent Publications

S.P. Benz, F.L. Walls, P.D. Dresselhaus, C.J. Burroughs,

“Low-distortion Waveform Synthesis with Josephson Junction Arrays,” Proc. 8th Int’l Superconductive Electronics

Conf. (ISEC '01): 115-116; 19-22 June 2001, Osaka, Japan.

R.H. Hadfield, G. Burnell, M.G. Blamire, P.D. Dresselhaus,

S.P. Benz, “Nanofabricated SNS Junction Series Arrays in

Superconductor-Normal Metal Bilayers,” Proc. 8th Int’l

Superconductive Electronics Conf. (ISEC '01): 391-392; 19-

22 June 2001, Osaka, Japan.

H. Yamamori, M. Itoh, H. Sasaki, A. Shoji, S.P. Benz, P.D.

Dresselhaus, “Fabrication of all-NbN digital-to-analog

converters for a programmable voltage standard,” Proc. 8th

Int’l Superconductive Electronics Conf. (ISEC '01): 219-220;

19-22 June 2001, Osaka, Japan.

S. P. Benz, J. M. Martinis, S. W. Nam, W. L. Tew, D. R.

White, “A new approach to Johnson noise thermometry using

a Josephson quantized voltage source for calibration,” to

appear in Proc. of TEMPMEKO 2001, 8th Int’l Symp. on

Temperature and Thermal Measurements in Industry and

Science, April 2001 (in press).

C.A. Hamilton, S.P. Benz, “Broadband Josephson voltage

standards,” submitted to the Microwave Conf. Digest of the

2001 Int’l Microwave Symp., to appear in the Special Symposium Issue of the IEEE Trans. on Microwave Theory and

Techniques, December 2001 (in press).

S.P. Benz, C.J. Burroughs, P.D. Dresselhaus, “AC coupling

technique for Josephson waveform synthesis,” IEEE Trans.

Applied Superconductivity 11(1): 612-616 (June 2001).

B. Jeanneret, A. Rüfenacht, C.J. Burroughs, “Comparison

Between the SNS and SIS Josephson Voltage Standards at

OFMET,” IEEE Trans. Instrumentation and Measurement,

50(2): 188-191 (April 2001).

S.P. Benz, C.J. Burroughs, P.D. Dresselhaus, L.A. Christian,

“AC and DC Voltages from a Josephson Arbitrary Waveform

Synthesizer,” IEEE Trans. on Instrumentation and Measurement, 50(2): 181-184 (April 2001).

S.P. Benz, P.D. Dresselhaus, C.J. Burroughs, “Nanotechnology for next generation Josephson voltage standards,” Proc.,

Symp. on Microtechnology in Metrology and Metrology in

Microsystems: 127-132; 31 August-1 September 2000, Delft

University of Technology, Delft, The Netherlands; also to

appear in IEEE Transactions on Instrumentation and Measurement, December 2001 (in press).

The larger voltage

has enabled 10

times lower uncertainty for acto-ac comparisons as compared

to previous

measurements

using lumped

arrays.
 6 Electronics and Electrical Engineering Laboratory

Nanoscale Cryoelectronics

Goals

To develop novel integrated circuits for metrology based on the unique properties of electronic

devices operating at temperatures below one

Kelvin.

Atomic force microscope image of an electron

counter, the heart of a new capacitance standard

based on counting electrons. The standard,

shown in the schematic, consists of the electron

counter, a capacitor, and a single-electron

electrometer to monitor the process (not shown).

The electron counter, based on seven nanometerscale tunnel junctions in series, can “pump”

electrons onto the capacitor with a error rate of

less than 1 electron in 108

.

Customer Needs

We work in two principal areas: single-electron

devices and microcalorimeter-based detectors.

The goal of the single-electron project is to use

the unique capabilities of single-electron tunneling (SET) devices to create new quantum standards based on the manipulation of single electrons and to develop measurement techniques

applicable to new generations of electronics that

will operate with very few electrons. The goal of

the microcalorimeter detector project is to use the

unique low-noise, high-sensitivity properties of

cryogenic electronics to create new generations

of detectors for high energy-resolution measurements of radiation, from infrared through X ray.

We have also begun two new programs: work to

significantly improve Johnson noise thermometry

using state-of-the-art room temperature electronics and Josephson junction voltage standards, and

work on quantum computing and quantum coherence.

Single Electron Devices for Electrical and Photonic Standards

The U.S. electronics industry continues to seek

improved and more accessible standards for

maintaining instrument calibration. NIST is

working to support this need through the development of intrinsic standards based on fundamental physical principles, such as the volt, based

on the Josephson effect, and the ohm, based on

the quantum Hall effect. For capacitance, NIST’s

primary standard (the calculable capacitor) is a

unique instrument that is difficult to replicate,

and it currently provides the best accuracy at only

one fixed frequency.

We are focused on producing a capacitance

standard based on counting electrons. This standard will provide accurate calibrations over a

wide range of frequencies and will be more easily

replicated to meet customers’ needs. This same

technology is being explored as a way to create

new optical calibration devices based on the

production of single photons.

Technical Strategy

The creation of electronic devices capable of

manipulating and detecting individual electrons

has opened the door to the development of entirely new standards and metrology tools. SET

devices are made possible by a combination of

state-of-the-art nanolithography to create the

nanometer-scale devices, millikelvin cryogenics

to cool the devices to their operating temperature,

custom low-noise electronics to operate and

measure the devices, and fundamental physics, to

understand and diagnose the operation of the

devices. Maintaining expertise and capabilities

across these fields represents the core technical

strategy of this effort.

We will compare measurements on SET devices

to theoretical models to understand the

performance and operating margins of the

capacitance standard.

At present, the main application for SET devices

within the project is to create a new capacitance

standard based on the fundamental definition of

capacitance: capacitance is stored charge per unit

voltage, C=Q/V. By placing a known number of

electrons on a capacitor, and measuring the

voltage across the capacitor, C can be determined. A prototype of such a standard has been

demonstrated with repeatability on order of 1 part

Technical Contact:

David Rudman

Staff-Years (FY 2001):

10 NIST staff

8.25 Other staff

We have already

demonstrated a

prototype capacitance

standard based on

counting electrons

one at a time.
 Electromagnetic Technology Division 7

in 107

. In order to confirm the accuracy of the

standard, a portable version must be taken to

NIST in Gaithersburg for direct comparison with

the calculable capacitor.

Using a new variable-frequency capacitance

bridge and capacitance artifacts calibrated

against the calculable capacitor, we will perform

improved accuracy measurements on the SET

standard in Boulder.

In collaboration with the Electricity Division, we

will build a new copy of the SET capacitance

standard in a portable millikelvin refrigerator to

allow transport to Gaithersburg and direct

comparison with the calculable capacitor.

With the availability of electron pumps, it may be

possible to perform unique comparisons of the

three intrinsic electrical standards: the volt (based

on the Josephson junction), the ohm (based on

the quantum Hall effect) and now the ampere

(based on counting electrons). This test, known

as the quantum-metrology triangle, will provide

new understanding and confidence in these

quantum standards. The experiments will require

a significant increase in current from the electron

pump.

We will develop a superconducting version of the

electron pump with a goal of providing sufficient

current for the metrology triangle experiments.

SET devices can also be used as tools to measure

the performance of other devices that operate

with individual electrons. Work has begun on

creating a new class of electronic devices designed to produce single photons on demand.

These devices will be based on quantum dots of

semiconductor materials. To understand their

behavior, it will be necessary to measure the

electrical currents into the dots at the single

electron level. This can be done only using SET

technology.

In collaboration with the Optoelectronics Division,

we will integrate SET devices into a single photon

circuit and confirm the electrical operation of the

photon source.

Accomplishments

 The past few years have brought to fruition

the results of a decade of research into SET

electronics. The goal of this work has been to

develop a capacitance standard based on counting

electrons. A thorough understanding of the

physics of SET devices has been necessary to

count electrons with metrological accuracy. The

fundamental error mechanisms in the electron

pump have been the subject of theoretical and

experimental investigations in the project for

several years. The development of an experimental technique for characterizing individual

junctions in the pump made possible the first

quantitative comparison between experiment and

theory in the regime of very rare errors. This

comparison showed that the pump was not performing nearly as well as the standard theory

predicted. Experiments and theoretical work on

the effect of photon-assisted tunneling, which is

not included in the standard theory, have shown

that this is probably the origin of the discrepancy.

This expanded theory remains a powerful tool for

predicting and diagnosing the performance of the

electron pump.

 A prototype of a capacitance standard based

on counting electrons has now been demonstrated. The components of the standard are an

electron counter, a capacitor, and an electrometer

to monitor the process. The electron counter is

based on seven nanometer-scale tunnel junctions

in series. It can “pump” electrons onto the capacitor with an error rate of less than one electron

in 108

. The electron pumping is monitored with

an SET-based electrometer fabricated on the

same chip as the pump, with a charge sensitivity

better than 10–2 electrons. The capacitor, fabricated by Neil Zimmerman in the Electricity

Division (811), operates at cryogenic temperatures and uses vacuum as the dielectric, resulting

in a frequency-independent capacitance.

Demonstration of pumping electrons on to and

off a prototype capacitance standard.

To operate the standard, approximately 100

million electrons are placed, one at a time, on the

capacitor. The voltage across the capacitor is then

measured, resulting in a calibration of the cryogenic capacitor. This capacitance can then be

transferred to room temperature using a standard

ac bridge measurement technique. The figure

above shows the result of pumping electrons on

and off the capacitor, with a 20 second pause

To evaluate the

electron counting

capacitance standard, we will compare it with the

present calculable

capacitor.

Work has begun on

creating a new class

of electronic devices designed to

produce single

photons on demand.
 8 Electronics and Electrical Engineering Laboratory

when fully charged to measure the voltage. The

result is a value of capacitance with a repeatability of one part in 107

.

Recently the dependence of pump errors on

voltage across the pump has been measured for

the first time. This directly gives the operating

margin for the feedback that must be maintained

during operation of the capacitance standard, a

critical design parameter for the next generation

of the standard. It has also been determined that

the pump can be cycled to temperatures in the

range of 50 K without affecting the noise performance. This will allow the standard to be

operated in an adiabatic demagnetization refrigerator, a much simpler cryogenic system than the

current dilution refrigerator.

An AFM image of electron-beam lithographicallywritten contact to a single QD. The black triangle

indicates where the QD is located. The lead that

approaches the QD from the bottom is used to

capacitively couple the QD to a single-electron

transistor structure. The white lines coming in

from the left side of the micrograph are alignment marks.

 The past two years have produced significant

progress towards the development of a singlephoton turnstile, a device designed to generate

single photons on demand using quantum dots

(QD) and single-electron principles. The first step

towards this end requires the development of a

process to allow electrical contact to individual

quantum dots. The process uses a combination of

photolithography, electron-beam lithography,

atomic-force microscopy, etching, and film

deposition to allow individual QD, which are

only a few tens of nanometers in diameter, to be

located and connected to microscopic leads on

the same chip. Each of the 12 steps in the process

has been executed individually with good yield,

and fabrication of a completed chip with contact

to four separate quantum dots will be pursued

next. An AFM image of electron-beam lithographically-written contacts to a single quantum

dot is shown at left.

Cryogenic Detectors

The ability to detect photons with high energy

resolution and near-unity quantum efficiency will

enable new generations of spectroscopic tools to

be created. Improved energy-dispersive X-ray

spectroscopy will be used to solve a wide range

of problems in materials analysis. For example,

the semiconductor manufacturing industry needs

improved X-ray materials analysis to identify

small contaminant particles on wafers and to

evaluate very thin layers used in current device

structures.

To make this technology available to the materials analysis community, NIST has licensed

several patents to two U.S. companies for commercialization. Additionally, NIST’s Chemical

Science and Technology Laboratory will use this

spectroscopy to improve its own materialsanalysis capability. The National Aeronautics and

Space Administration (NASA) also needs improved instruments for imaging at wavelengths

from infrared to X-ray. We are working with

NASA to bring this technology into use.

The same devices can also be used to detect

single optical photons such as are conceived to be

used in the future for quantum information and

communication systems. We are working to

apply this technology to the measurement of

these entangled photons.

Technical Strategy

Introducing a radically new technology such as

cryogenic microcalorimeters to a large community requires creating and demonstrating an entire

measurement instrument, not just the detector. In

this case, we have developed superconducting

electronics to read the detectors, compact adiabatic demagnetization refrigerators to simplify

cooling the detectors to millikelvin operating

temperatures, and room-temperature electronics

to process the output signals. The resulting system makes a much more compelling case for the

technology than the performance specifications

of the detector alone. Thus, our goal is to develop

new detector systems and to apply those systems

to problems of interest to our customers.

We will provide technology transfer support to

the NIST licensees commercializing this

technology.

In the area of X-ray spectroscopy, the performance target depends on the application. For materials analysis, further improvements in energy

resolution are not as important as an increase in

the maximum count rate and collection area. This

Our detectors will

help the semiconductor industry to

improve yield by

identifying small

contaminant

particles.
 Electromagnetic Technology Division 9

can be achieved by the creation of multipixel

arrays of detectors. In addition to the fabrication

difficulties in making such arrays, the cold- and

room-temperature electronics to read out the

arrays must also be created. The current approach

to the electronics is to develop a superconducting quantum interference device

(SQUID) multiplexer (MUX) circuit to read the

array, and room-temperature digital signal processing (DSP) to process the MUX signals.

We will fabricate, instrument and test a small

array of x-ray microcalorimeter detectors to

demonstrate the increase in collection area and

count rate achievable through arrays.

The application of X-ray detectors to materialsanalysis problems represents a test bed for this

technology. With a focus towards the semiconductor manufacturing industry, problems in

characterization of small particles and very thin

layers of material are very important. The ability

of the detector to differentiate overlapping X-ray

lines at low energies enables analysis of previously inaccessible systems.

We will provide the Chemical Science and

Technology Laboratory (CSTL) of NIST with a

complete prototype system for collaborative use

in studying problems of interest to our

customers.

For some materials-analysis applications and for

astronomical observations, improvements in the

energy resolution at relatively high X-ray energies (6000 eV) are still needed. In addition, largeformat, densely packed arrays of detectors are

required for imaging. These are ambitious goals

that will require improved understanding of the

limitations on performance of microcalorimeter

detectors. Novel fabrication techniques will need

to be developed to make densely packed arrays,

and SQUID MUX and DSP circuitry will be

required to read out the arrays.

We will develop models of single-pixel

microcalorimeter performance to assist in

improving detector sensitivity, and will fabricate

and test novel detector designs based on these

models.

We will develop improved bulk and/or surface

micromachining techniques to allow fabrication of

dense packed arrays of detectors.

These detectors also provide remarkable performance at lower energies, from infrared

through visible. In the visible, single-photon

microcalorimetry is still possible, opening a

range of interesting applications. In the field of

quantum information and communication, the

detection of single photons is a key measurement

requirement. In a new program funded through

DARPA, we are working to develop a multichannel single-photon detection system that will

allow detection and analysis of correlated photons. A similar system is also being developed

for optical imaging spectroscopy.

We will develop a single-photon microcalorimeter

system, and in collaboration with Boston

University, use it to analyze correlated photons.

With Stanford University, we will develop a 32

pixel optical imaging microcalorimeter

instrument.

For infrared applications, the goal is clearly to

develop large-format imaging arrays with high

sensitivity and energy resolution. The present

application for these arrays is in astronomy, both

ground-based and in space.

We will develop arrays of detectors optimized for

imaging infrared bolometry, along with the

necessary wiring, SQUID MUX and room

temperature DSP electronics to read the array.

Accomplishments

 The success of the microcalorimeter detector project has been made possible by broad

expertise within the Division in such fields as

physics superconductivity, device fabrication

including Si micromachining, superconducting

electronics, cryogenic engineering, and lownoise, room-temperature electronics. Without

expertise in all of these areas, the complete

systems that have provided the compelling

demonstrations for the power of this technology

would not have been possible. As an example,

the schematic on the next page shows a microcalorimeter energy-dispersive spectrometer

(EDS) X-ray detector system inserted into a

scanning electron microscope to allow chemical

microanalysis of materials.

The ability of the

microcalorimeter

detector to differentiate overlapping X-ray lines

enables analysis

of previously

inaccessible systems.

Introducing a

radically new

technology such

as cryogenic microcalorimeters to

a large community requires

creating and

demonstrating an

entire measurement instrument,

not just the detector.
 10 Electronics and Electrical Engineering Laboratory

Schematic of a microcalorimeter energydispersive spectrometer (EDS) X-ray detector

system inserted into a scanning electron microscope.

 The microcalorimeter detector uses a superconducting/normal-metal bilayer to create a

superconducting transition-edge sensor (TES).

Using the proximity effect, the transition temperature of the bilayer can be selected to match

each specific application. We created an accurate

model of the proximity effect in this system,

which allows the thickness for each layer to be

calculated, minimizing trial-and-error fabrication.

 Originally each TES was individually fabricated using Al/Ag bilayers and a shadow-mask

deposition process, but recent advances with

Mo/Cu bilayers have allowed whole-wafer photolithographic processing. The TES and appropriate X-ray absorber are fabricated on a Si3N4

micromachined membrane to produce the required thermal isolation. The device operates

using a current bias and extreme negative electrothermal feedback, so that it self-regulates in

temperature. Absorbed X rays produce heat

pulses in the device, which are read out as pulses

of reduced bias current by a first-stage, singleSQUID amplifier located adjacent to the detector

to minimize inductance. The output of the firststage SQUID is read out by a unique 100-SQUID

amplifier invented and fabricated by the Division

specifically to allow direct coupling of the signal

to room-temperature electronics. The detector is

cooled to below 100 mK by a compact adiabatic

demagnetization refrigerator, which has unique

design features that produce nearly 24 hours of

continuous operation, and days of hold time for

liquid helium.

Comparison of resolutions of NIST microcalorimeter EDS to standard semiconductor EDS.

This system holds the world record for energy

resolution for an EDS detector of 2.0 eV at 1500

eV, which is over 30 times better than the best

high-resolution semiconductor-based detectors

currently available. The figure above compares

an X-ray spectrum obtained with this system to

that from a semiconductor energy-dispersive

detector, clearly demonstrating the remarkable

improvement in resolution. The specimen was a

glass prepared by Dale Newbury of the Chemical

Science and Technology Laboratory to use as a

test standard for EDS. We have used the system

to identify submicrometer particles of materials

such as W on Si substrates, an identification

problem that is impossible with standard EDS

detectors and of great importance to the semiconductor industry. It has also demonstrated energy

shifts in the EDS X-ray spectra of materials such

as Al, Fe, and Ti, depending on their chemical

bonding state, thus allowing differentiation

between a particle of Al and Al2O3, for example.

Furthermore, we have completed several effective partnerships with companies in the semiconductor industry to demonstrate the usefulness of

the microcalorimeter spectrometer for practical

analysis. For example, in collaboration with

researchers at Lucent Technologies in Orlando,

Florida, we critically compared the ability of

microcalorimeter-based x-ray analysis to detect

trace Cu with that of other industrial analytical

techniques, including conventional semiconductor Energy-Dispersive Spectrometry (EDS),

Auger Electron Spectrometry, and Secondary Ion

Mass Spectrometry (SIMS). Although only

SIMS is capable of analysis of trace Cu down to

the ~0.02 % atomic level, microcalorimeter EDS

fared very well in comparison with the other nondestructive analytical techniques.

The key innovation

for absolute noise

thermometers is a

Josephson-junction

calculable noise

voltage source.

The success of the

microcalorimeter

detector project has

been made possible

by the broad expertise within the

division in such

fields as physics of

superconductivity,

device fabrication

including Si micromachining, superconducting electronics, cryogenic

engineering, and

low noise, roomtemperature electronics.
 Electromagnetic Technology Division 11

A microcalorimeter EDS spectrum of 0.7 % by

weight Cu/Al alloy thin film (from Lucent Technologies) demonstrating the sensitivity of microcalorimeter EDS for analysis of trace Cu in the

semiconductor industry.

 In collaboration with the University of

Albany (NY), we have used the microcalorimeter

EDS to analyze ultra-thin films of TaSiN that are

under development as ion diffusion barriers in

integrated circuit (IC) interconnect structures

smaller than 0.1 micrometer. The figure below

compares the spectra taken with the microcalorimeter EDS to that taken with a conventional

semiconductor EDS. The high resolution of the

microcalorimeter EDS allows unambiguous

separation of the Ta M lines from the Si K lines,

even for films as thin as 3.5 nm. Such constituent identification is impossible with conventional

Si-based EDS detectors.

EDS spectra from a 3.5 nm thick TaSiN film on Si

taken with a beam voltage of 3 keV. The solid

line denotes EDS data taken using a microcalorimeter x-ray detector. Open circles denote EDS

data taken using a conventional Si(Li) detector.

Based on these types of results, two U.S. X-ray

spectrometer companies have acquired licenses

for a suite of patents covering this technology to

begin commercialization. Technology transfer to

both companies has occurred.

 To enable more advanced applications of this

technology to materials-analysis problems requires coupling the spectrometer to state-of-theart analytical tools, such as those available in the

Chemical Science and Technology Laboratory

(CSTL) at NIST-Gaithersburg. To this end, the

single-pixel spectrometer used in the above

research has been relocated to Gaithersburg.

Installation will be completed once a new detector is available, and the system will be used

jointly with CSTL to continue microanalytical

work on problems of interest to the semiconductor and other materials-intensive industries.

 In addition to X-ray detection, this microcalorimeter technology is being developed for

use at other wavelengths, from optical down

through the sub-millimeter. Our TES bolometers

have achieved world-record sensitivity for infrared radiation. This impressive result confirms the

utility of this technology for this application as

well. However, to meet the needs of NASA,

large-format arrays of these detectors have to be

fabricated, and electronics have to be created to

read out the arrays. We have developed the first

SQUID-based MUX for this purpose, and have

demonstrated it with a 1 x 16 array of TES bolometers. This array and MUX have been delivered to NASA, and were first field-tested in the

spring of 2001 on the Cal Tech Submillimeter

Observatory located in Hawaii. The devices

performed as expected, and will be used for

further observations this fall.

A photograph of an 8-channel SQUID multiplexer

chip fabricated at NIST. On the 6.4 mm chip are 8

first-stage SQUID amplifiers and one secondstage series-array SQUID amplifier. This chip has

been used to multiplex 8 channels at 1 million

samples per second.

500 1000 1500 2000

0

500

1000

1500

2000

2500

0

50

100

850 900 950 1000

C-K Cu-L

O-K W-M

W-M

W-M

Si-K

Counts (0.16 eV/channel)

Energy (eV)

Cu L 1

NIST cal EDS

3 keV beam energy

1.3 nA beam current

500 s-1 input rate

1000 s live time

Cu L 1,2

1600 1700 1800 1900 2000

0

500

1000

1500

2000

2500

Si K

Si K 3,4 satellit e

Ta M

Ta Mα

Si Kα1,2

Energy (eV)

β β

α

Our compact adiabatic demagnetization refrigerator has

unique design features that produce

nearly 24 hours of

continuous operation, and days of

hold time for liquid

helium.

This system holds

the world’s record

for energy resolution for an EDS

detector.

The system has

demonstrated for

the first time EDS

energy shifts depending on chemical bonding state.
 12 Electronics and Electrical Engineering Laboratory

We have also invented a new SQUID MUX

concept that (in models) will have better bandwidth and 2 orders of magnitude lower power

dissipation than the present design. The first

fabrication run yielded devices that work at the

design specifications. High-speed testing and

noise analysis will be performed this fall.

 The ability to handle the data read out from

large arrays of detectors may, in the end, prove as

important as the performance of the detectors

themselves. Even once a multiplexing technology

is developed, the huge amount of data acquired

from this system will require new roomtemperature electronics to collect and process the

information. We developed a first-generation

digital signal-processing (DSP) system and have

successfully interfaced it with the SQUID amplifiers, providing the feedback required for their

operation. In collaboration with Stanford University, these electronics have been used with a

small array (2 x 2) of optical TES detectors (built

by Stanford) to perform astronomical observations at the McDonald Observatory. Using the

electronics, real-time data were acquired from the

Crab pulsar at higher rates than had been previously achieved. A new 32-channel system is

currently being built in collaboration with Stanford.

 This detector technology has also been

explored as a means of providing new capabilities in the field of mass spectrometry. The microcalorimeter can detect the kinetic energy associated with the impact of an accelerated ion on the

detector. We have demonstrated the use of this

energy measurement to determine the charge of

incident ions created using an electro-spray ion

source (ESI). ESI is widely used for mass spectrometry of biomolecules because it creates gasphase ions directly from liquid input. One important drawback of ESI is that it creates ions

with a wide range of charge states, leading to

many peaks in the measured spectrum of massto-charge ratio. This difficulty limits the utility of

ESI for complicated samples such as mixtures.

The use of an energy-resolving detector can in

principle provide a solution to this difficulty by

allowing an independent measurement of the

ionic charge, which can then be used to deconvolve the spectra. We have demonstrated this

technique with a variety of proteins (masses up to

77 kDa), and used this technique to analyze a

mixture of calibration proteins. While this technique showed promise, the impact-energy resolution is currently insufficient for widespread

application. We have currently suspended work

in this area.

New Projects

The technical expertise in the project lends itself

to the creation of new projects. Over the past two

years two new efforts have been started: Johnson

Noise Thermometry and Quantum Computing.

Both are in the early stages, but significant results

are expected within the next few years.

Technical Strategy

The development of DSP electronics for the

detector project stimulated interest in applying

this technology to other metrology problems.

Electronic thermometers based on Johnson noise

have been limited by electronic measurement

capabilities. In collaboration with the Josephson

Array Technology Project and the Chemical

Science and Technology Laboratory, we have

begun work to develop Johnson noise thermometers using state-of-the-art analog and digital

electronics. The key innovation will be the creation and use of a Josephson junction-based Arbitrary-Waveform Synthesizer to generate a calculable-noise voltage source to provide accurate

calibration of the amplifiers and correlators

needed to make the thermometer. The goal is to

make a highly accurate noise thermometer that

can be easily replicated for use in a wide variety

of applications.

We will develop and test the analog and digital

electronics needed to realize a new generation of

Johnson noise thermometers.

There has been considerable worldwide interest

in using coherent quantum states as a new type of

“bit” (qubit) in a computer. To date the most

successful demonstration of this concept has used

a few trapped ions as the qubits. There has also

been research into using superconducting devices

to establish the required coherent quantum states.

However, it has proved difficult to create devices

with coherence times long enough to be considered useful.

John Martinis has conceived of a new way of

using Josephson junctions (JJ) to create qubits for

a potential quantum computer. Extensive modeling of the behavior of JJ suggested that a practical qubit could be built using superconducting

circuits. The modeling, which included noise

sources such as 1/f noise, led to a conclusion that

large, rather than small, junctions should improve

performance of the qubit.

Under funding from the NSA preliminary devices

have already been fabricated based on this model.

Three iterations of the initial design have been

made and tested. Significant attention (modeling

The ability to read out

large arrays of detectors may, in the

end, prove as important as the detectors

themselves.

This detector technology may provide

new capabilities in

mass spectrometry.
 Electromagnetic Technology Division 13

and testing) has been paid to the microwave

properties of the inductor. The results have been

encouraging: energy relaxation times are now

compatible with the design values.

We will design, fabricate and test Josephson

junction devices as potential qubits.

Recognition

 Presidential Early Career Award for Scientists and Engineers to Mark Keller, 2000.

 NIST Condon Award, for excellence in

writing, 2000.

 NIST Applied Research Award, Cryogenic

X-ray Detector, 1999.

 Department of Commerce Gold Medal,

Cryogenic X-ray Detector, 1999.

Patents

 "Particle Calorimeter with Normal Metal

Base Layer," issued June 1997.

 "Mechanical Support for a Two Pill Adiabatic Demagnetization Refrigerator," issued

August 1999.

 "Superconducting Transition-Edge Sensor,"

issued March 1999.

 "Microcalorimeter X-ray Detectors with Xray Lens," issued March 1999.

 "Superconducting Transition-Edge Sensor

with Weak Links," filed November 1998.

 "The Use of Superconductor-InsulatorNormal (SIN) Tunnel Junctions in Superconducting Quantum Interference Device (SQUID)

Multiplexers," disclosure submitted, April 2000.

Recent Publications

Single Electron Devices

A.L. Eichenberger, M.W. Keller, J.M. Martinis, N.M. Zimmerman, “Frequency Dependence of a Cryogenic Capacitor

Measured Using Single Electron Tunneling Devices,” J. Low

Temp. Physics 188, 317 (2000).

R.L. Kautz, M.W. Keller, J.M. Martinis, “Noise-Induced

Leakage and Counting Errors in the Electron Pump,” Phys.

Rev. B 62, 1588 (2000).

N.M. Zimmerman, M.W. Keller, “Dynamic Input Capacitance of Single-Electron Transistors and the Effect on

Charge-Sensitive Electrometers,” J. Appl. Phys. 87, 8570

(2000).

A.L. Eichenberger, M.W. Keller, J.M. Martinis, N.M. Zimmerman, "Measurement of the Frequency Dependence of a

Single-Electron Tunneling Capacitance Standard,” Proc.,

Conf. on Precision Electromag. Meas. (CPEM) 2000, 16-17

(2000).

M. Covington, M.W. Keller, R.L. Kautz, J.M. Martinis,

"Photon-assisted Tunneling in Electron Pumps," Phys. Rev.

Lett. 84, 5192 (2000).

M.W. Keller, N.M. Zimmerman, A.L. Eichenberger, J.M.

Martinis, "A Capacitance Standard Based on Counting

Electrons," Proc. Conf. on Precision Electromag. Meas.

(CPEM) 2000, 317-318 (2000).

R.L. Kautz, M.W. Keller, J.M. Martinis, "Leakage and

Counting Errors in a Seven-Junction Electron Pump," Phys.

Rev. B 60, 8199 (1999).

M.W. Keller, A.L. Eichenberger, J.M. Martinis, N.M. Zimmerman, "A Capacitance Standard Based on Counting

Electrons," Science, 285, 1706 (1999).

Cryogenic Detectors

R.E. Geer, D. Wu, D.A. Wollman, “High-resolution EDS

Analysis of Ultra-Thin TaSiN Diffusion Barriers for Cu

Metallization Using Microcalorimetry,” Proc. IEEE 2001 Int'l

Interconnect Tech. Conf., 192-194 (2001).

S.W. Nam, D.A. Wollman, D.E. Newbury, G.C. Hilton, K.D.

Irwin, D.A. Rudman, S. Deiker, N.F. Bergren, J.M. Martinis,

“Progress Towards Arrays of Microcalorimeter X-ray Detectors,” J.M., Microscop. & Microanal. 7 (Suppl. 2: Proc.),

1050-1051 (2001).

S. Deiker, J. Chervenak, G.C. Hilton, K.D. Irwin, J.M.

Martinis, S. Nam, D.A. Wollman, “Transition Edge Sensor

Array Development,” IEEE Trans. Appl. Supercond. 11, 469-

472 (2001).

G.C. Hilton, J.M. Martinis, K.D. Irwin, N.F. Bergren, D.A.

Wollman, M.E. Huber, S.W. Nam, “Microfabricated Transition-Edge X-ray Detectors,” IEEE Trans. Appl. Supercond.

11, 739-742 (2001).

K.D. Irwin, M.E. Huber, “SQUID Operational Amplifier,”

IEEE Trans. Appl. Supercond. 11, 1265 (2001).

M.E. Huber, P.A. Neil, R.G. Benson, D.A. Burns, A.M.

Corey, C.S. Flynn, Y. Kitaygorodskaya, O. Massihzadeh,

J.M. Martinis, G.C. Hilton, “DC SQUID Series Array Amplifiers with 120 MHz Bandwidth,” IEEE Trans. Appl. Supercond. 11, 1251-1256 (2001).

K.D. Irwin, G.C. Hilton, J.M. Martinis, S. Deiker, N.F.

Bergren, S.W. Nam, D.A. Rudman, D.A. Wollman, “A MoCu Superconducting Transition-Edge Microcalorimeter with

4.5 eV Energy Resolution at 6 keV,” Nuclear Instrum. and

Methods in Physics Research A 444, 184-187 (2000).

D.A. Wollman, S.W. Nam, D.E. Newbury, G.C. Hilton, K.D.

Irwin, N.F. Bergren, S. Deiker, D.A. Rudman, J.M. Martinis,

“Superconducting Transition-Edge-Microcalorimeter X-ray

Spectrometer with 2 eV Energy Resolution at 1.5 keV,” Nucl.

Instrum. and Methods in Phys. Res. A 444, 145-150 (2000).
 14 Electronics and Electrical Engineering Laboratory

J.M. Martinis, G.C. Hilton, K.D. Irwin, D.A. Wollman,

"Calculation of Tc in a normal-superconductor bilayer using

the microscopic-based Usadel theory," Nuclear Instruments

and Methods in Physics Research A 444, 23 (2000).

J.A. Chervenak, E.N. Grossman, K.D. Irwin, J.M. Martinis,

C.D. Reintsema, C.A. Allen, D.I. Bergman, S.H. Moseley, R.

Shafer, "Performance of multiplexed SQUID readout for

Cryogenic Sensor Arrays," Nuclear Instruments and Methods

in Physics Research A 444, 107 (2000).

D.A. Wollman, S.W. Nam, G.C. Hilton, K.D. Irwin, N.F.

Bergren, D.A. Rudman, J.M. Martinis, D.E. Newbury,

"Microcalorimeter Energy-Dispersive Spectrometry Using a

Low Voltage Scanning Electron Microscope," J. Microscopy

199, 37-44 (2000).

S. Nam, D.A. Wollman, G.C. Hilton, J. Chervenak, S.

Deiker, K.D. Irwin, J.M. Martinis, "A Digital Readout

Scheme for Arrays of Microcalorimeter X-ray Detectors,"

Proc. Microscopy and Microanal. 2000, 742-743 (2000).

J. A. Chervenak, K. D. Irwin, E. N. Grossman, J. M. Martinis,

C. D. Reintsema, M. E. Huber, "Superconducting Multiplexer

for Arrays of Transition Edge Sensors," Appl. Phys. Lett. 74,

4043 (1999).

C. K. Stahle, D. McCammon, K. D. Irwin, "Quantum Calorimetry," Physics Today 52, 32 (1999).

D.A. Wollman, S.W. Nam, D.E Newbury, G.C. Hilton, K.D.

Irwin, N.F. Bergren, S. Deiker, D.A. Rudman, J.M. Martinis,

"Superconducting transition-edge-microcalorimeter x-ray

spectrometer with 2eV energy resolution at 1.5 keV," Nuclear

Instruments and Methods in Physics Research A 444, 145

(2000).

K.D. Irwin, G.C. Hilton, J.M. Martinis, S. Deiker, N.F.

Bergren, S.W. Nam, D.A. Rudman, D.A. Wollman, "A MoCu superconducting transition-edge microcalorimeter with 4.5

eV energy resolution at 6 keV," Nuclear Instruments and

Methods in Physics Research A 444, 184 (2000).
 Electromagnetic Technology Division 15

Terahertz Technology

Goals

To develop and apply electronic technology,

especially cryogenic electronic technology, in the

terahertz spectral range to measurements and

standards in support of other NIST organizations

and U.S. industry.

Customer Needs

The U.S. aerospace and defense industries are

being pushed toward both higher performance

and faster, less expensive systems. Devices

originally developed for cryogenic electronics, in

particular cryogenic bolometers and tunnel diodes, are often useful in a wide variety of metrological applications, as well as in other scientific or commercial applications, not always at

cryogenic temperatures. Atmospheric scientists

use satellite-based spectrometers to monitor the

worldwide distribution of species relevant to

climate change. Security equipment manufacturers are developing millimeter-wave imagers for

concealed weapons detection. And submillimeter

spectroscopy is being developed as a diagnostic

tool—monitoring species concentrations and

temperatures—for plasma processes in semiconductor manufacturing. The activities of this

project focus on adapting millimeter-wave to IR

technology for the benefit of these industries,

either directly through collaborative research and

development programs, or indirectly, by improving the metrological capabilities of other

NIST Divisions, which in turn make the results

available to U.S. industry.

Technical Strategy

The work of this project focuses particularly on

bolometric detectors, initially developed for

cryogenic electronic applications, but also useful

in the detection or frequency conversion of

radiation from millimeter to infrared wavelengths. Work on improving the sensitivity or

precision of power measurements exploits the

low noise properties of thin-film bolometers.

One focus is the development of bolometers with

ever-higher sensitivity, and their incorporation

into imaging systems based on large focal-plane

arrays. Depending on engineering tradeoffs we

make during the design phase, (i.e. between

sensitivity and other characteristics such as

operating temperature), these imagers are applicable to remote sensing of the Earth, atmospheric

spectroscopy, or astronomy. Some of this work

is supported by the National Aeronautics and

Space Administration (NASA), and its contractors in the aerospace industry.

We will develop a high-sensitivity bolometer for

far-IR wavelengths with an noise equivalent

power (NEP) of less than 10–18 watts per root

hertz.

Because readout is a critical element in any array

technology, a SQUID-based cryogenic multiplexer is being developed to provide the frontend processing of the bolometers’ outputs. The

bolometers are superconducting films biased on

their transition edge, and operated in an electrical

substitution mode.

Monolithic SQUID multiplexer circuit. A 1 × 8

prototype has been demonstrated at pixel rates

of 1 megahertz.

Far-infrared spectroscopy at the highest levels of

sensitivity and spectral resolution has traditionally been accomplished with heterodyne techniques, in which the weak signal to be measured

is combined with a strong “local oscillator” and

focused onto a detector or “mixer.” The signal at

the difference frequency is then measured with an

ultra-low-noise detection system. A program is

underway to develop ultra-sensitive mixer elements based on superconducting hot-electron

bolometers (HEBs). Like the transition-edge

bolometer arrays, a major application for these

mixers lies in space-based, remote sensing. HEBs

formed of thin films of niobium and niobium

nitride have already demonstrated sensitivities

within a factor of 5 of the fundamental quantum

limit. The focus of our research, and of the most

Technical Contact:

Erich Grossman

Staff-Years (FY 2001):

2 NIST staff

3 Other staff

Our large arrays of

bolometers are

applicable to remote

sensing of the earth,

atmospheric

spectroscopy, and (by

NASA) astronomy.

Recent advances in

nanoscale fabrication

make the vision of

direct rectification of

sunlight much more

realistic.
 16 Electronics and Electrical Engineering Laboratory

recent progress in the state of the art, lies in

extending the frequency coverage of this measurement technique above 2 THz, allowing measurement of a wider variety of species, and in

developing integrated heterodyne arrays.

By 2002, we will demonstrate a 2 x 2 element

heterodyne mixer array operating at 2.5 THz,

with noise temperature within a factor of 10 of

the quantum limit.

We also use superconducting bolometers to

standards-related metrology, both for audio

frequencies (where they are known as AC-DC

thermal transfer standards) and for IR frequencies

(where they are known as electrical substitution

radiometers). This project is collaborative with

the Electricity Division, which is responsible for

AC electrical calibration and metrology.

For audio frequencies, we will achieve precision

better than 1 part in 106

 in AC voltage transfer at

microwatt power levels.

In addition, we are working on the application of

uncooled terahertz bolometer arrays to analyze

and diagnose problems in the etching plasmas

used for semiconductor manufacturing. These

plasmas typically contain a number of molecular

and ionic species, whose concentrations and

temperatures can be accurately monitored by

spectroscopy on their pure rotational transitions,

which lie in the terahertz spectral region. A

collaborative program with the Physics Laboratory, funded by the NIST Advanced Technology

Program (ATP), was started in FY 2001 to demonstrate the usefulness of this technique as an

industrial plasma diagnostic, and to develop a

practical system that can be applied to it. A key

part of this program is the development of bolometer arrays with sufficient sensitivity to perform the spectroscopy, but which are not cryogenically cooled, and are therefore practical for

industrial use. Based on prior work done for

other programs, a detector system based on

uncooled Nb bolometers has been designed and

built; an example device is shown in the next

figure.

By 2002,we will integrate an uncooled THz

bolometer with the Physics Lab ‘s Gaseous

Electronics Conference (GEC) plasma reactor and

backward-wave oscillator sources, and perform

spectroscopy on a CF2 plasma.

We also develop thin-film bolometers, coupled to

antennas and operated at room temperature, in

applications where the very highest sensitivity is

not required. An example is millimeter-wave

imaging for the detection of concealed weapons

(clothing is transparent at millimeter wavelengths). In collaboration with the Electricity

Division and the Office of Law Enforcement

Standards, we are developing an actively illuminated imaging system for this application, based

on a full wafer-scale array of several hundred

antenna-coupled bolometers. The technical

emphasis in this case is on development of a

practical system, rugged enough and low enough

in cost to allow for field deployment, for example

with mobile police units or in airports.

We will develop an imaging system with

reflectivity contrast less than 5 % at a range of 5

meters in a 120-element array.

First version of a 120-element antenna-coupled

bolometer array for detection of concealed

weapons.

In most of these programs, the lithographic

antenna forms an important component of the

system, frequently requiring as much development as the bolometer or tunnel diode, although

its only function is the efficient coupling of

radiation to the device. We therefore perform

significant development work on lithographic

antennas themselves. These are ubiquitous in

wireless telecommunications systems (e.g. cellular phones) at lower, microwave frequencies.

The relentless drive for greater bandwidth in such

telecom systems is driving a push to raise the

operating frequencies to the millimeter-wave

range or beyond, where our present antenna

development effort is focused. Moreover, the

polarization-specific nature of antennas can

frequently be exploited to provide our devices

with additional functionality. For example, the

emittance or reflectance properties of a surface

differ for s and p polarizations of obliquely

incident radiation. This can be exploited to resolve the ambiguity inherent in noncontact thermometry or materials analysis due to unknown

specimen emissivity. In collaboration with a

Our millimeter wave

imaging is being

evaluated for

concealed weapons

detection.
 Electromagnetic Technology Division 17

commercial semiconductor metrology manufacturer, we are exploring the potential of this technique.

Accomplishments

 First electrical substitution radiometer based

on superconducting sensors — In 1997, we

completed a standards-grade, electrical substitution radiometer for measurement of mid- and farIR-wavelength blackbody radiation, and delivered it to the Optical Technology Division, which

is responsible for optical and IR power calibration and metrology. For an extended series of

experiments covering a range of substitution

power from 500 picowatts to 5 microwatts, the

instrument’s noise floor could be approximated

as 4 picowatts plus 7 × 10−6

 times the measured

power. We are now assisting a U.S. manufacturer

of cryogenic radiometers with the incorporation

of superconducting sensors into its products.

 First ac-dc thermal transfer standard based

on superconducting sensors — In 1998, we

completed and reported a set of preliminary

experiments on ac-dc transfer using similar

transition-edge bolometers. These yielded errors

varying from 50 to 150 × 10–6 (for frequencies

from 100 hertz to 10 kilohertz), limited chiefly by

inaccuracy introduced in delivering the ac signal

to the cryogenic reference plane.

 First SQUID-based multiplexer for transition-edge bolometers — In far-IR astronomical

applications (both imaging and low-resolution

spectroscopy), speed, and therefore sensitivity,

are both limited by the number of pixels that can

be read simultaneously. Present far-IR bolometer

arrays are already at the practical limit for lowtemperature wire count, so further improvement

requires cold multiplexing. Over the last 2 years,

a novel SQUID-based multiplexing scheme was

conceived and demonstrated in a 1 × 8 channel

prototype. It operates at pixel rates up to 1 megahertz, and has noise sufficiently low to multiplex

up to about 250 channels without degrading the

system noise.

 First monolithic arrays of transition-edge

bolometers for space astronomy — These 1 × 8

arrays are prototypes of a new generation of

detector arrays for low-background, far-infrared

astronomy, and were spotlighted in a recent

article in Superconductor and Cryoelectronics

magazine. The Al-Ag or Mo-Au arrays are fabricated on micromachined Si structures that enable

construction of closely packed two-dimensional

arrays by folding the “legs” back out of the focal

plane. The bolometers operate with a 300 millikelvin base temperature requiring 3

He refrigeration, and have a saturation power of about 5

picowatts and a time constant of about 2 milliseconds. Electrical NEP is phonon-noise limited

at roughly 2 × 10–17 watts per root hertz, the best

ever reported for an IR bolometer operating with

3

He refrigeration, and within a factor of six of the

best reported for any other IR bolometer.

 A novel slot-ring antenna design for uncooled millimeter-wave bolometer arrays –

Imaging applications in the terahertz spectral

range require large numbers of pixels, reasonable

sensitivity, and reasonable cost. One approach to

achieving all three goals simultaneously is use of

lithographic antennas to couple the radiation into

micrometer-sized detectors. In this case, the

antenna engineering challenge is to develop an

array-compatible antenna with the highest possible directivity in a completely planar monolithic

structure. This is the motivation behind a new

antenna design we have developed, in which slotring antennas with finite groundplanes are patterned on electrically thin substrates. Because the

application is imaging, sensitivity to radiation

from only one side of the substrate is desired, so

a planar backshort is employed to reflect radiation from the backside of the substrate into the

forward direction. With the backshort at the

proper position behind the plane of the slot-ring

antenna, constructive interference occurs between

the directly received radiation and that reflected

by the backshort, increasing the directivity.

Measured beam patterns are highly circular and

exceptionally narrow (22 ̊ at –3 dB) from a

completely planar antenna. They can be arrayed

at a spacing of 1.5 wavelengths with negligible

measured effect on performance. A 120-element

array for 95 GHz has been fabricated.

 Uncooled antenna-coupled Metal-InsulatorMetal (MIM) junctions for IR rectification and

mixing — The ultra-low capacitance, fully lithographic diodes have areas as low as 30 × 30

square nanometers and are fabricated by angled

evaporation through a free-standing PMMA resist

bridge defined by electron beam lithography. The

diodes are coupled to planar dipole antennas

designed for resonance at a wavelength of 10

micrometers. We have successfully fabricated

and tested diodes from Al-AlOx-Al, Al-AlOx-Pd,

and Nb-NbOx-Ag materials. The nonlinear current-voltage characteristics are accurately predicted by the Brinkman-Dynes-Rowell theory of

tunneling through trapezoidal barriers, both for

the nano-MIMs and for separate, micrometerOur 300 mK infrared

bolometers have the

best noise equivalent

power ever reported.

Our nano-MIM diodes

have clearly rectified

10 μm infrared radiation.
 18 Electronics and Electrical Engineering Laboratory

sized Nb-NbOx-Ag MIM diodes. The latter show

barrier heights that can be controllably modified

by in-situ Ar-ion milling following the barrier

growth. The optical response of the nano-MIM

diodes to CO2 laser radiation at 10 micrometers

was clearly proven to arise from classical rectification. Previous attempts to develop fully lithographic MIM diodes, on the other hand, all foundered on the difficulty of separating optical

signals due to rectification from those due to

thermal mechanisms. The nonlinearity observed

in the large-area diodes is, according to theory,

sufficient to enable observation of photonassisted tunneling steps, a phenomenon observed

at room temperature only recently in GaAs heterostructures.

Recent Publications

J.A. Chervenak, K.D. Irwin, E.N. Grossman, K.D. Irwin, J.M.

Martinis, C.D. Reintsema, C.A. Allen, D. Bergman, S.H.

Moseley, R. Shafer, “Performance of Multiplexed SQUID

Readout for Cryogenic Sensor Arrays,” Nuclear Inst. Methods

A, in press.

M.E. MacDonald, A. Alexanian, R.A. York, Z. Popovic, E.N.

Grossman, “Spectral transmittance of Lossy Printed Resonant-Grid Terahertz Bandpass Filters,” IEEE Trans. Micro.

Theory Tech., v. 48 (4) p. 712 (2000).

S. Nolen, J.A. Koch, N. Paulter, C.D. Reintsema, E.N.

Grossman, “Antenna-Coupled Niobium Bolometers for mmWave Imaging Arrays,” Proc. SPIE, v. 3795 p. 279 (1999).

J.A. Chervenak, K.D. Irwin, E.N. Grossman, J.M. Martinis,

C.D. Reintsema, M.E. Huber, “Superconducting Multiplexer

for Arrays of Transition Edge Sensors,” Appl. Phys. Lett. 74,

4043-4045 (June 1999).

C.D. Reintsema, E. N. Grossman, J.A. Koch, “Improved VO2

Microbolometers for Infrared Imaging: Operation on the

Semiconducting-Metallic Phase Transition with Negative

Electrothermal Feedback,” Proc. SPIE 3698, 190-200 (April

1999).

E. Gerecht, C.D. Reintsema, E.N. Grossman, A.L. Betz, R.T.

Boreiko, “Superconducting Nb DHEB Mixer Arrays for FarInfrared Spectroscopy,” Proc. 12th Intl. Symp. on Space

Terahertz Technology, (Feb. 2001)

S. Nolen, T.E. Harvey, C.D. Reintsema, E.N. Grossman

“Properties of Cavity-backed Slot-ring Antennas at 95 GHz,”

Proc. SPIE v. 4373, p. 49(2001)

S. Nolen, C.D. Reintsema, E.N. Grossman, “Slot-ring Antennas with a Planar Backshort designed for Millimeter-wave

Imaging Applications,” submitted to IEEE Antennas and

Propagation Lett. (2001)

E.N. Grossman, T.E. Harvey, C.D. Reintsema, “Controlled

Barrier Modification in Nb/NbOx/Ag Metal Insulator Metal

Tunnel Diodes,” submitted to J. Appl. Phys. (2001)

E.N. Grossman, S. Nolen, N.G. Paulter, C.D. Reintsema,

“Concealed Weapons Detection System using Uncooled,

Pulsed, Imaging Arrays of Millimeter-wave Bolometers,”

Proc. SPIE, v. 4373, p 7, (2001)

N.G. Paulter, E.N. Grossman, G.N. Stenbakken, B.C. Waltrip,

S. Nolen, C. D. Reintsema, “Design of An Active Mm-wave

Concealed Object Imaging System,” Proc. SPIE. V.4373, p.

64 (2001)
 Electromagnetic Technology Division 19

High Tc Electronics

Goals

To aid and accelerate the development of new

thin-film materials and devices for electronic

applications, especially high temperature superconductors (HTS), thin film oxides, and microelectromechanical systems (MEMS).

Pulsed-laser deposition chamber for oriented

growth of complex oxides.

Customer Needs

We support the emerging HTS electronics industry through measurements that enable the development of HTS devices and circuits. Our customers are also those other NIST Divisions

responsible for standards and measurement

techniques in areas such as voltage; infrared,

millimeter wave, and microwave radiation; and

time and frequency standards. In addition, we

support other government agencies, including the

National Aeronautic and Space Administration

(NASA), the Office of Naval Research (ONR),

the National Security Agency (NSA) and the

Defense Advanced Research Projects Agency

(DARPA).

Technical Strategy

We consider three criteria when selecting research projects: importance for standards improvement and development; importance but precompetitive in the commercial sector; and the

inclusion of a strong component of innovative

science and technology.

To address these criteria, we have developed

fabrication processes, testing capabilities, and

theoretical competence for advanced cryogenic

materials and devices at rf, microwave and millimeter-wave frequencies. We use pulsed laser

deposition to grow novel thin-film materials and

take those materials through the device design

and processing steps to final test. We have also

developed techniques for fabricating micromachined structures to aid in metrology for a

number of different technological areas. We

actively collaborate with U.S. and international

standards laboratories that provide materials and

make comparative measurements. Below we

describe the efforts in the two major thrusts of

our project: cryogenic microwave measurements

and devices, and novel micro- and nano-scale

devices.

Microwave measurements and devices

We work with the HTS communications industry

to measure and improve the capabilities of HTS

devices. The rapidly expanding wireless communications industry has begun to adopt HTS components in receiver front-ends. This effort is

driven by the need for more efficient use of a

limited spectrum in the face of an increasing

amount of interference and signal from other

providers. The introduction of third- and fourthgeneration technology for the wireless Internet

has created a new market for improved passive

and active devices. Our work is aimed at addressing some of the unresolved issues in HTS

devices that affect their ultimate performance. In

particular, the nonlinear response of HTS-based

microwave devices is not well understood and is

a serious problem for communications applications.

We will perform measurements of the

microwave-frequency nonlinear signal generation

in commercially produced HTS materials for the

purpose of determining the source of the

nonlinear response in HTS devices.

We will transfer low-frequency measurement

techniques for screening unpatterned films for

nonlinear response to HTS communication

industry partners.

We collaborate with the Radio-Frequency Technology Division to improve both linear and

nonlinear microwave measurement and characterization techniques for thin-film materials and

devices, particularly at cryogenic temperatures.

We also investigate new materials and device

structures for achieving low-loss electronically

tunable microwave circuits.

We will develop superconducting devices to be

used as model nonlinear elements for detailed

evaluation using a Nonlinear Network

Measurement System in collaboration with the

Nonlinear Device Characterization Project in the

Radio-Frequency Technology Division.

Technical Contact:

James Booth

Staff-Years (FY 2001):

5 NIST staff

.25 Other staff

The rapidly expanding

wireless

communications

industry has begun to

adopt HTS

components in

receiver front-ends.

We have implemented

a cryogenic

microwave probe

station for broadband

(dc to 40 GHz)

characterization of

temperaturedependent microwave

properties.
 20 Electronics and Electrical Engineering Laboratory

We will improve methods for measuring the

broadband permittivity of ferroelectric thin films

as a function of temperature and bias voltage.

We are participating in developing a new standard for measuring the surface resistance RS of

ultra-low-loss superconducting thin films. This is

under the auspices of the International Electrotechnical Commission (IEC) and the Versailles

Agreement on Advanced Materials and Standards

(VAMAS).

We will continue development and improvements

in our implementation of the proposed

international standard technique for measuring

surface resistance at microwave frequencies.

Cryogenic microwave probe station.

Micromachining and MEMS

MEMS and nanoelectromechanical systems

(NEMS) are the enabling technology for entire

new generations of electronic systems. Novel

sensor and metrology technologies benefit from

the ability to use integrated-circuit fabrication

paradigms in constructing mechanical devices.

Our work in this area also includes measurement

techniques for evaluation of novel MEMS structures at rf and microwave frequencies.

We will continue research efforts in support of

the Time and Frequency Division while

developing new processes and applications.

We will develop new measurement techniques for

characterizing MEMS elements at cryogenic

temperatures.

Accomplishments

Microwave measurements and devices

 Loss and nonlinearity limit the utility of

HTS and tunable-dielectric-based components in

communications applications. Superconductivity

can significantly improve the sharp band edges of

filters, reduce insertion loss in most passive

components, and eliminate dispersion in transmission lines. HTS materials have been improved

to the point that they rival their low-temperature

counterparts in surface resistance, RS; however,

power handling and nonlinearity are not yet fully

understood or controlled in the manufacturing

environment. In contrast, tunable dielectric thinfilm materials, which offer the promise of electronic tuning of microwave circuit elements on

nanosecond time scales, suffer from excessive

loss at microwave frequencies, the origin of

which loss is unknown. Our measurements are

performed with a unique cryogenic microwave

probe station to enable precise characterization of

patterned devices. The project has achieved

significant technical progress in several areas of

study related to microwave measurements and

devices implementing HTS materials, tunable

dielectric materials, and MEMS structures.

View of two 40 GHz probes and a sample of YBCO

devices in the probe station.

 Intercomparison of nonlinearity – Using the

measurement techniques we have developed in

collaboration with the Naval Research Laboratory (NRL), we have conducted a study of nonlinearity using four measurement techniques. We

have shown that there is a distributed source of

geometry-independent nonlinearity that is clearly

associated with a current-dependent penetration

depth. These measurements span frequencies

from 2 kHz to 18 GHz. In addition, the results

obtained using our measurement techniques

compare well with results obtained from Passive

InterModulation (PIM) measurements and Nonlinear Network Measurement System (NNMS)

measurements for the same superconducting

device, made in collaboration with the Nonlinear

Device Characterization Project in the RF Technologies Division. We are now beginning to

study devices made from films produced by HTS

filter companies, with the goal of comparing our

measurements to the performance of the filters

made from identical thin films.

“Dr. Beall [of the

High Tc Electronics

Project] has

generously helped us

with technical advice

and processing

assistance which in

turn has had a

significant impact on

advancing our

prototypes. We hope

our relationship with

NIST will continue.”

- Astralux, Inc.,

Boulder, CO

MEMS and nanoelectromechanical

systems (NEMS) are

the enabling

technology for entire

new generations of

electronic systems.
 Electromagnetic Technology Division 21

 Nonlinear phase measurements – We have

succeeded in measuring for the first time the

phase of the nonlinear signal generated by HTS

devices at microwave frequencies, also in collaboration with the Nonlinear Device Characterization Project in the Radio-Frequency Technology Division. The value of the phase of the

nonlinear signal provides important information

on the origin of the nonlinear response in HTS

materials. In addition, a superconducting device

could be used to calibrate the relative phase of

higher harmonics in a nonlinear measurement

system. We are currently developing improved

circuits with the goal of more accurate nonlinear

phase measurements of HTS-based devices.

 Microwave signal limiter developed – It is

possible to build extremely sensitive digital

circuits using low-temperature superconducting

(LTS) Josephson junction technology. However,

such circuits can be vulnerable to transient overpower conditions such as lightening strikes or

unintended radar illumination. We have designed, fabricated and tested an HTS microwave

signal limiter for the purpose of protecting an

ultra-sensitive LTS analog-to-digital converter

from such over-power conditions. The device

makes use of the microwave current-induced

transition from the very low-loss superconducting

state to the high-loss normal state, and has been

shown to have extremely wide bandwidth

(> 40 GHz). Reversible operation has been

demonstrated at microwave powers up to 10

watts, and switching speeds for transitions between the limiting and non-limiting states have

been measured to be on the order of microseconds. Improved designs and further testing for

the signal limiter are currently underway.

 Measurements of dynamic effects in frequency-dependent permittivity of tunable dielectric thin films – Recent measurements in our

project of ferroelectric thin films have revealed

large relaxation effects at high microwave frequencies that have not been previously observed.

Ferroelectric thin films are potentially valuable

because they possess a dielectric permittivity that

can be modified by the application of a relatively

modest bias voltage. Such a tunable dielectric

material would enable very fast tuning of microwave elements such as filters, and would also

enable cheaper phased-array antennas. Our

measurements have revealed that the high microwave losses that to date have limited the

application of ferroelectric thin films are at least

in part due to coupling of energy into lattice

modes of these materials. We are aggressively

pursuing ways to engineer the lattice dynamics in

these materials in order to optimize their performance at microwave frequencies.

 Comparison of tuning and nonlinear response in tunable dielectric thin films – A major

issue in the application of tunable dielectric thin

films for microwave elements is the response

times over which one can vary the permittivity

using an applied bias field. We have performed

nonlinear harmonic generation measurements as

a way of deducing switching times for these

materials on the nanosecond scale. By comparing the tuning due to the rf field within the device

derived from such harmonic-generation measurements with the tuning induced by a dc bias

field, we have been able to show that tuning in

these materials is possible on nanosecond time

scales or faster. Further nonlinear measurements

are being pursued in order to determine tuning

times for different materials and also as a way of

assessing the detrimental nonlinear properties

that might arise in a tunable application.

 Measurements of MEMS structures at cryogenic temperatures – We have modified our

cryogenic microwave probe station to allow for

the application of large bias voltages in order to

enable measurements of MEMS structures at

cryogenic temperatures. So far, several sets of

devices, designed and fabricated by the Electrical

Engineering Department of the University of

Colorado, have been tested at both room temperature and cryogenic temperatures. These

initial measurements indicate that the MEMS

structures will function at cryogenic temperatures, which will allow for ultra-low-loss MEMS

and combination MEMS/superconductor structures to be designed and evaluated.

 International draft standard for surface

resistance – A draft standard for surface resistance RS using dielectric resonators has been

written, and round-robin testing in Japan has

begun. We have completed the first set of comparative measurements in our laboratory. Good

agreement was observed for values of the superconductor RS and the sapphire loss tangent in the

initial temperature-dependent measurements, and

further improvements to the measurement apparatus are underway.

Micromachining and MEMS

We use our new MEMS facilities to fabricate

novel structures that enable new measurements

and devices in a number of different areas.

We have developed a

model system to

investigate different

HTS structures for

nonlinear microwave

response, and can

test a variety of thin

films, fabrication

processes, and

structure dimensions

to achieve improved

performance.

“Working with Jim

[Beall, of the High Tc

Electronics Project]

has been a great help

to us. We have

benefited in

particular from Jim’s

experience with

silicon device

fabrication.”

-Precision Photonics

Corp.
 22 Electronics and Electrical Engineering Laboratory

 Micromachined structures for ion traps – We

have made micromachined structures for use in

ion traps, in collaboration with the Physics Laboratory’s Time and Frequency Division. They

have recently demonstrated quantum entanglement with four ions in one of these traps. Recent

traps made with improved surfaces have had

much smaller anomalous heating, leading to

improved ion-storage times. We are proceeding

with development of ion traps fabricated from

silicon electrodes, which should have even higher

quality.

 MEMS facility – The new facility for furnace processing of silicon is in routine use by

several projects. We have developed improved

cantilevers for magnetometers in collaboration

with the Magnetic Technology Division. We are

presently exploring collaborations to work on

MEMS and NEMS devices for new metrological

instruments, both internally with the Chemical

Sciences and Technology Laboratory (CSTL) and

externally with local companies. We have recently added a XeF2 gas-phase silicon isotropic

etch system that allows rapid dry etching of

silicon. This is useful for releasing membranes

and other delicate structures. This process was

used for development of a silicon nitride pop-updetector structure and a surface-micromachined

thermal-isolation platform structure, both of

which have applications in detector array technologies.

Cryogenic linear quadrapole Hg ion trap used for

atomic frequency standard experiments.

Collaborations

 We held the first NIST-Boulder MEMS

Working Group meeting in December 2000,

which was attended by NIST personnel from

several laboratories as well as members of the

local university and industrial MEMS community. This was an opportunity for researchers

across the community to meet become aware of

activities in the area.

Recent Publications

J.C. Booth, C.L. Holloway, E.F. Kuester, “Modeling Linear

and Nonlinear Inductive Effects in Superconducting Planar

Circuits,” Record of the 2001 IEEE Electromagnetic Compatibility International Symposium, pp. 594-599 (2001).

J.C. Booth, L.R. Vale, R.H. Ono, “Comparative studies of the

microwave nonlinearities in high temperature superconducting films and devices,” Physica C 357-360: 1516-1520

(2001).

H. Shimakage, R.H. Ono, L.R. Vale, “Interface Engineered

Josephson Junctions Optimized for High Jc,” IEEE Transaction on Applied Superconductivity 11(2): 4032-4035 (2001).

L.R. Vale, R. H. Ono, “Small Area, “Thin Films of YBCO for

Applications in Hot Electron Bolometers,” IEEE Transaction

on Applied Superconductivity 11(1): 762-765 (2001).

J.C. Booth, L.R. Vale, R.H. Ono, “On-Wafer Measurements

of Nonlinear Effects in High Temperature Superconductors,”

IEEE Transaction on Applied Superconductivity 11(1): 1387-

1391 (2001).

J.C. Booth, L.R. Vale, R.H. Ono, J.H. Claassen, “Power

Dependent Impedance of High Temperature Superconductors

Thin Films: Relation To Harmonic Generation,” J. Supercond. 14(1): 65-72 (2001).

J.C. Booth, L.R. Vale, R.H. Ono, “Broadband Determination

Of Microwave Permittivity and Loss in Tunable Dielectric

Thin Film Materials,” in Materials Issues for Tunable RF and

Microwave Devices, Proceedings, Materials Research Society

Symposium,Vol. 603, 253-264, Q. Jia, Ed., Warrendale, PA

(2000).

J.C. Booth, J.A. Beall, D.A. Rudman, L.R. Vale, R.H. Ono,

“Geometry Dependence of Nonlinear Effects in High Temperature Superconducting Transmission Lines at Microwave

Frequencies,” J. Appl. Phys. 86, 1020-1027 (July 1999).

J.C. Booth, C.L. Holloway, “Conductor Loss in Superconducting Planar Structures: Calculations and Measurements,”

IEEE Trans. Micro. Theory Tech. 47, 769-773 (June 1999).

J.H. Claassen, J.C. Booth, J.A. Beall, D.A. Rudman, L.R.

Vale, R.H. Ono, “Nonlinear Inductive Response of High

Temperature Superconducting Films Measured by the Mutual

Inductance Technique,” Appl. Phys. Lett. 74, 4023-4025

(June 1999).

H. Shimakage, R.H. Ono, J.C. Booth and L.R. Vale, “Third

Harmonic Generation in Bicrystal Junctions,” Superconductor

Science and Technology 12, 830-832 (1999).

L.R. Vale, R.H. Ono, D.G. McDonald and R. Phelan, “Large

area YBCO Bolometers on Si,” Superconductor Science and

Technology 12, 856-858 (1999).

J.C. Booth, L.R. Vale, R.H. Ono, J.H. Claassen, “Predicting

Nonlinear Effects in Superconducting Microwave Transmission Lines from Mutual Inductance Measurements,” Superconductor Science and Technology 12, 711-713 (1999).

J.H. Claassen, J.C. Booth, J.A. Beall, D.A. Rudman, L.R.

Vale, R.H. Ono, “Comparison of Microwave and Mutual

Inductance Measurements of the Inductive Nonlinearity of

HTS Thin Films,” Superconductor Science and Technology

12, 714-716 (1999).

C. Weber, J.C. Booth, L.R. Vale, R.H. Ono, A.M. Klushin, H.

Kohlstedt, R. Semerad, “Coplanar Transmission Lines with

Quantum

entanglement of

four ions has been

demonstrated in a

micromachined ion

trap.
 Electromagnetic Technology Division 23

Meandering Center Conductors in YBCO/Au Bilayers,”

Superconductor Science and Technology 12, 998-1000

(1999).

J.C. Booth, J.A. Beall, L.R. Vale, R.H. Ono, “Distributed

Nonlinear Effects In Planar Transmission Lines,” 53rd

Automated RF Techniques Group (ARFTG) Digest, 31 – 40

(Jun 1999).

D.A. Rudman, F.J.B. Stork, J.C. Booth, J.Y. Juang, L.R. Vale,

G.J. Beatty, C.I. Williams, J.A. Beall, R.H. Ono, S.B. Qadri,

M.S. Osofsky, E.F. Shelton, J.H. Claassen, G. Gibson, J.L.

MacManus-Driscoll, N. Malde, L.F. Cohen, “Role of Oxygen

Pressure during Deposition on the Microwave Properties

YBCO Films,” IEEE Trans. Appl. Supercond. 9, 2460-2464

(Jun 1999).

D.G. McDonald, R.J. Phelan, Jr., L.R. Vale, R.H. Ono, D.A.

Rudman, “Passivation, Transition Width, and Noise for

YBCO Bolometers on Silicon,” IEEE Trans. Appl. Supercond. 9, 4471-4474 (Jun 1999).

J.C. Booth, J.A. Beall, D.A. Rudman, L.R. Vale, R.H. Ono,

C.L. Holloway, S.B. Qadri, M.S. Osofsky, E.F. Shelton, J.H.

Classen, G. Gibson, J.L. MacManus-Driscoll, N. Malde, L.F.

Cohen, “Simultaneous Optimization of the Linear and

Nonlinear. Microwave Response of YBCO Films and Devices,” IEEE Trans. Appl. Supercond. 9, 4176-4179 (Jun

1999).

H.Q. Li, R.H. Ono, L.R. Vale, D.A. Rudman, S.H. Liou,

“Interactions Between Bicrystal Josephson Junctions in a

Multilayer Structure,” IEEE Trans. Appl. Supercond. 9, 3417-

3420 (Jun 1999).

L.R. Vale, R.H. Ono, J. Talvacchio, M.G. Forrester, B.D.

Hunt, M.S. DiIorio, K-Y. Yang, and S. Yoshizumi, “Long

Term Stability of YBCO Based Josephson Junctions,” IEEE

Trans. Appl. Supercond. 9, 3382-3385 (Jun 1999).

J.C. Bergquist, R.J. Rafac, B.C. Young, J. Beall, W.M. Itano,

D.J. Wineland, “Sub-Dekahertz Spectroscopy of 199Hg+,”

Proc. SPIE Conference, Laser Frequency Stabilization,

Standards, Measurement, and Applications (ed. J. Hall and J.

Ye), 1-7 (13 Mar 2001).

B.C. Young, R.J. Rafac, J.A. Beall, F.C. Cruz, W.M. Itano,

D.J. Wineland, J.C. Bergquist, “Hg+ Optical frequency

Standard: Recent Progress,” submitted to Proc. 14th Int. Conf.

on Laser Spectrosc., World Scientific, Singapore (20 Jul

1999).

R.J. Rafac, B.C. Young, F.C. Cruz, J.A. Beall, J.C. Bergquist,

W.M. Itano, D.J. Wineland, “199Hg+ Optical Frequency

Standard: Progress Report,” Proc. Joint Mtg. 13th European

Frequency and Time Forum and 1999 IEEE Int. Freq. Cont.

Symp., Besancon, France, April 13-16, 676-681 (13 Apr

1999).

R. Rafac, B. Young, J. Beall, W. Itano, D. Wineland, J.

Bergquist, “Sub-Dekahertz Ultraviolet Spectroscopy of

199Hg+,” Phys. Rev. Lett., 85, 2462-2465 (18 Sep 2000).
 24 Electronics and Electrical Engineering Laboratory

Nanoscale Fabrication

Our facilities for fabricating integrated circuits

are essential to nearly all of the work in the

Division. We maintain a research-class facility

for superconductor and MEMS structures.

Beginning with computer-aided design, we use

electron-beam and optical lithography to make

structures smaller than 100 nm and complex

circuits containing as many as 32,000 Josephson

junctions. Our tools are housed in 200 m2

 of

“class 100” cleanroom space, which was improved greatly in 1999. We also added tools for

fabricating MEMS that in the past have been

essential for many of our ultra-sensitive instruments, and for micromachined ion traps for

future clocks. We are applying these techniques

to novel magnetic instruments and photon

detectors.

Maggie Crews (left), Jim Beall and Jay Koch in

the lithography bay of the cleanroom.

Our near state-of-the-art facilities are open-shop.

All of our staff, and occasional visitors, can

personally use them after appropriate training. To

avoid constraining research activities to fixed

design rules and to allow maximum creativity our

processes are flexible. Our past accomplishments

are testimony to the success of our approach.

Computer-controlled research tube furnaces for

growth of SiO2, Si3N4, and other CVD materials.

For patterning at the 1 μm scale, we use optical

lithography in an I-line stepper and a deep-UV

contact aligner. Electron-beam lithography enables patterning at less than 100 nm. Our facilities support fabrication of superconductor integrated circuits and MEMS fabrication, as well as

laser ablation of thin films of high-temperature

superconductors. We recently installed a set of

tube furnace reactors (5" capable), shown above,

for wet and dry silicon oxidation, solid-source

diffusion of boron, low-stress silicon nitride/polysilicon low-pressure chemical vapor

deposition (LPCVD), and LPCVD of lowtemperature oxide.

In the past year we have upgraded our optical

pattern generator to a modern instrument capable

of making masks with feature sizes of 1.5 micrometers. Having an in-house mask-making

facility allows very rapid turnaround, which

improves productivity and encourages creativity.

Our capability in electron beam lithography has

been expanded with the addition of a second

scanning electron microscope with wafer-scale

stages and load lock. We have added a silicon

dry-etch tool that uses xenon difluoride gas to

isotropically etch silicon without liquids. We

have completed procurement of two new sputterdeposition tools that will allow contaminationfree systems for depositions of SNS junctions and

superconducting bilayers. We are also in the

procurement phase for a deep silicon reactive ion

etch system.
 Electromagnetic Technology Division 25

Appendix A:

Experimental Systems and Instruments

A partial list of our measurement facilities and capabilities follows:

Experimental environments include a dilution refrigerator (DR) for temperatures down to

30 mK and adiabatic demagnetization refrigerators (ADR) for cooling to 50 mK. The DR cools

the capacitance standard to less than 50 mK and has special filtering to provide a noise-free

environment for the standard. See the Nanoscale Cryoelectronics Project section of this publication for more information on the capacitance standard based on counting electrons.

Mark Keller (left) and John Martinis The microcalorimeter system connected

with the dilution refrigerator used for the to an SEM for x-ray analysis.

capacitance standard based on counting

electrons.

Measurement systems include: high-speed electrical test facilities, an atomic-force microscope, a scanning electron microscope (SEM), high-resolution X-ray materials analysis, X-ray

structural analysis, a high-resolution mass spectrometer with electrospray source, variabletemperature microwave probe station, Josephson voltage standards, and tools for characterizating microwave loss in thin films and detailed properties of infrared antennas. The figure

on the above right is a photograph of an ADR with an x-ray microcalorimeter spectrometer

attached to a commercial SEM.
 26 Electronics and Electrical Engineering Laboratory

Appendix B:

Postdoctoral Opportunities

NIST offers postdoctoral associateships in collaboration with the National Research Council

(NRC). Research topics and associated advisors for the Electromagnetic Technology Division

are listed below. Please see our Web site at http://emtech.boulder.nist.gov for full details on

each opportunity. Contact a prospective adviser to discuss details of proposed work and the

application process. If you do not find a topic that exactly matches your interest, please

contact an advisor in a similar discipline. U.S. citizenship is required for postdoctoral appointments.

Research Topic Advisor(s)

Superconducting and Nanometer-Scale Devices for Infrared to Millimeter

Wave Applications

Erich Grossman

Applications of Superconducting Integrated Circuits and Josephson Junction ArraysSam Benz

Functional Materials and Systems for RF/Microwave/mm-Wave Electronics James Booth

Linear and Nonlinear Microwave Response of Oxide Thin Films and DevicesJames Booth

High-Tc Superconductors: Devices, Device Physics, and Circuits James Booth

Micromachined Materials and Devices for Metrological Applications James Booth

James Beall

Richard Harris

Physics and Applications of Single Electron Tunneling Devices Mark Keller

A Capacitance Standard Based on Counting Electrons Mark Keller

Characterization of Single-Photon Turnstiles Using Single-Electron Tunneling DevicesMark Keller

Superconducting Detectors for Photons from the Infrared through X Rays Kent Irwin

John Martinis

High-Resolution Microcalorimeters for X-Ray Microanalysis Gene Hilton

John Martinis

David Rudman

Quantum Computing using Superconducting Devices John Martinis
 Electromagnetic Technology Division 27

Appendix C:

Awards and Recognition

Notes: * indicates a coworker from outside the Electromagnetic Technology Division

Medal awards are from the U.S. Department of Commerce

Award Recipient Date Notes

William A. Wildhack

Award

Robert A. Kamper October,

1972

National Conference of Standards Laboratories

Arnold O. Beckman

Award (ISA)

Robert A. Kamper 1974 Instrument Society of America, no citation

Gold Medal James E. Zimmerman and

Robert A. Kamper

October,

1975

For innovative contributions to practical

precise measurements using superconducting quantum interference devices

(SQUIDs)

Industrial Research

-100 Award

Clark A. Hamilton, Robert

J. Phelan*, Gordon W.

Day*, John Geist*, and B.

McIntosh*

1975

NIST Condon Award Robert A. Kamper November,

1977

For distinguished achievement in written

exposition.

NBS Stratton Award James E. Zimmerman 1979

Silver Medal Clark A. Hamilton, Richard

E. Harris, Frances L. Lloyd,

and Robert L. Peterson

November,

1980

For creative advancement of the state of

the art in ultra-high-speed analog-to-digital

conversion.

NIST Condon Award Donald G. McDonald December,

1981

For distinguished achievement in written

exposition.

Silver Medal Michael. W. Cromar

Silver Medal Richard L. Kautz 1983 For fundamental contributions to the

understanding of chaotic behavior in Josephson junction devices.

Gold Medal Clark A. Hamilton 1983 For outstanding contributions to the development of ultra-high-speed Josephson

junction microcircuit technology.

NBS Fellow James E. Zimmerman 1984

EEEL Outstanding

Paper Award

Richard L. Kautz 1985 “Chaos and Thermal Noise in the rf-Biased

Josephson Junction,” Journal of Applied

Physics, Volume 58, Number 1 (1 July

1985).

NIST Stratton Award Richard L. Kautz and

Donald B. Sullivan

December,

1985

For exceptional accomplishments that

established the feasibility of a fundamental

improvement in the Josephson voltage

standard.

Research and Development Magazine Industrial Research

-100 Award

Clark A. Hamilton, Richard

L. Kautz and Frances L.

Lloyd

1986 For development of Josephson series array

voltage standards.

NBS Fellow Clark A. Hamilton 1987
 28 Electronics and Electrical Engineering Laboratory

NIST Gold Medal Clark A. Hamilton, Richard

L. Kautz, Frances L. Lloyd,

James A. Beall

October, 1989 For developing the first practical Josephson-junction series array voltage standards,

at both 1 V and 10 V levels, including the

U.S. primary standard.

IEEE Fellowship Robert A. Kamper 1989 For leadership and technical contributions

to the application of superconductivity in

instrumentation, measurement, and standards.

EEEL Outstanding

Paper Award

Samuel P. Benz and Charles J. Burroughs1991 “Coherent Emission from Two-Dimensional

Josephson Junction Arrays,” Appl. Phys.

Lett. 58(19): 2162-2164, May 1991

NIST Gold Medal High Temperature Superconducting Electronics

Team: James A. Beall,

Todd E. Harvey, Ronald H.

Ono, David A. Rudman,

etc

October,

1993

For the world’s best Josephson junction

and associated practical technology to put

the U.S. in the lead for superconducting

electronics

Department of Commerce Silver MedalRobert A. Kamper 1993 For leadership of NIST’s Boulder Laboratories and for excellent negotiating skills in

facilities development.

Harry Diamond Memorial Award (IEEE)Robert A. Kamper 1993 For pioneering the application of superconducting quantum mechanical principles to

metrology, directing development of advanced Cryoelectronics devices, and guiding a metrology program supporting the

lightwave industry.

EEEL Outstanding

Paper Award

John M. Martinis, Michael

Nahum, and Hans

Dalsgaard Jensen

1994 “Metrological Accuracy of the Electron

Pump,” Physical Review Letters, Volume

72, Number 6, pp. 904-907 (7 February

1994)]

EEEL Outstanding

Paper Award

Mark W. Keller, John M.

Martinis, Neil M. Zimmerman, and Andrew H.

Steinbach

1996 “Accuracy of Electron Counting Using a 7-

Junction Electron Pump,” Applied Physics

Letters, Volume 69, Number 12, pp 1804-

1806, 16 September 1996].

NIST Stratton Award John M. Martinis December,

1996

For applying new insights into quantum

phenomena to establish the fundamental

accuracy of Coulomb-blockage circuits for

single-electron counting

Silver Medal John Martinis December,

1996

For establishing the fundamental accuracy

of Coulomb-blockade circuits for singleelectron counting, providing the basis for

new intrinsic standards

EEEL Measurement

Services Award

Clark A. Hamilton February,

1995

EEEL Outstanding

Authorship Award

Mark W. Keller, John

M. Martinis, Neil Zimmerman, and Andrew H.

Steinbach

February,

1997

“Accuracy of electron counting using a 7-

junction electron pump,” Appl. Phys. Lett.

69(12), 1804-1806, 16 September 1996.

Allen V. Astin Award

(National Conference

of Standards Laboratories)

Samuel P. Benz, Clark A.

Hamilton, Charles J.

Burroughs, Todd Harvey,

and Lawrence Christian

1997 Josephson Standards for AC Voltage Metrology

Fellow of American

Physical Society, Condensed Matter Physics

John M. Martinis November,

1997

For his experimental investigations into the

fundamental quantum behavior of lowtemperature electronic devices
 Electromagnetic Technology Division 29

NIST Condon Award Richard L. Kautz December,

1997

For his extensive review of the physics of

the dc series array voltage standard in the

paper “Noise, chaos, and the Josephson

voltage standard,” which appeared in

Reports on Progress in Physics, vol. 59, pp.

935-992, Aug 1996.

Fellow of the American

Physical Society, Precision Measurements and

Fundamental Constants

Richard L. Kautz 1998 For experimental and theoretical investigations of Josephson junctions, particularly

the nonlinear dynamics of phase locking

and chaos, essential to the development of

practical series-array voltage standards.

Fellow of the American

Physical Society, Precision Measurements and

Fundamental Constants

Donald G. McDonald

EEEL Outstanding

Authorship Award

David A. Wollman, Kent D.

Irwin, Gene C. Hilton,

Laura L. Dulcie, Dale E.

Newbury, and John M.

Martinis

1998 “High-Resolution, Energy-Dispersive Microcalorimeter Spectrometer for X-Ray Microanalysis,” Journal of Microscopy, Volume

188, Pat 3, pp. 196-223, December 1997

NIST Applied Research

Award

Gene C. Hilton, Kent D.

Irwin, John M. Martinis,

and David A. Wollman

December,

1998

For inventing an x-ray detector, demonstrating its potential to revolutionize x-ray

microanalysis and developing it to the point

of commercialization

Gold Medal Gene C. Hilton, Kent D.

Irwin, John M. Martinis,

and David A. Wollman

December,

1998

For inventing a new x-ray detector, showing its potential to revolutionize x-ray

microanalysis, and bringing it to the point

of commercialization.

EEEL Outstanding

Authorship Award

Mark W. Keller, Ali L.

Eichenberger, John M.

Martinis, and Neil M.

Zimmerman

1999 “A Capacitance Standard Based on Counting Electrons,” Science, Vol. 285, 10 September 1999, pp 1706-1709

Presidential Early Career

Award for Scientists and

Engineers

Mark W. Keller October, 2000

NIST Condon Award Mark W. Keller, John M.

Martinis, Ali Eichenberger,

Neil Zimmerman

November,

2000

For distinguished achievement in written

exposition.

William H. Wildhack

Award

Clark Hamilton October, 2001 National Conference of Standards Laboratories

Symbols, Units, Nomenclature, Atomic Masses

and Fundamental Physical Constants

(SUNAMCO) Award

Clark Hamilton 2001 International Union of Pure and Applied

Physics (IUPAP)
 30 Electronics and Electrical Engineering Laboratory

Appendix D:

Electromagnetic Technology Division Staff

(December 2001)

Division Office

3776 Harris, Richard E. (Chief)

3678 Metz, Sara E. (Division Secretary)

3812 Schump, Jeanne (Admin. Officer)

3988 McCarthy, Sandy (Secretary)

5068 Copeland, Jill (Secretary)

Josephson Array Technology

5258 Benz, Sam (PL)

3906 Burroughs, Charlie

5211 Dresselhaus, Paul

3740 Hamilton, Clark (GR)

4218 Rogalla, Horst (GR)

Nanoscale Cryoelectronics

5081 Rudman, David (PL)

4137 Aumentado, Jose (PD)

5344 Bergren, Norm

4153 Beyer, Joern (GR)

4320 de Korte, Piet (GR)

3461 Deiker, Steven (PREP)

4280 Halford, Forrest (PREP)

5679 Hilton, Gene

3402 Huber, Martin (IPA)

5911 Irwin, Kent

3391 Kautz, Richard (GR)

5430 Keller, Mark

3597 Martinis, John

4212 Miller, Aaron (PD)

3148 Nam, Sae Woo

4325 Osborn, Kevin (PREP)

4319 Ruggiero, Steve (IPA)

5121 Vale, Leila

7457 Wollman, David

7894 Xu, Yizi (Ctr)

Terahertz Technology

5102 Grossman, Erich (PL)

3114 Bhupathiraju, Ashok (IPA)

4199 Gerecht, Eyal (IPA)

5052 Reintsema, Carl

4318 Salminen, Arto (GR)

High Tc Electronics

5989 Beall, Jim

7900 Booth, Jim

5049 Crews, Maggie

7064 Koch, Jay

5113 McDonald, Don (GR)

7213 Schima, Susan

Division website:

http://emtech.boulder.nist.gov/

Email addresses for all staff are:

firstname.lastname@boulder.nist.gov

Telephone numbers are: (303) 497-

XXXX (the four-digit extension as indicated).

Legend:

Ctr = Contractor

GR = Guest Researcher

IPA = Interagency Personnel Agreement

PD = Postdoctoral Appt.

PL = Project Leader

PREP = Professional Research Experience Prog.

PHASE = Practical Handson Application to Science

Education