bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) MOSFET Development in IBM–1963 to Present
Authors: Critchlow D. L.
Published: March 2014

Some of the highlights of the basic work, application requirements decisions, and product developments made in IBM on MOSFET technology are described. The work spans the pioneering work in n-channel in the 1960s through the 64-kbit RAM developments and exploratory work in the 1970s.
(Invited) Recent Progress in VAD Fiber Fabrication Process
Authors: Inagaki Nobuo , Edahiro Takao , Nakahara Motohiro
Published: March 2014

Since the development of the Vapor-phase Axial Deposition (VAD) process in 1977, rapid progress has been made in the improvement of transmission properties by the analysis of the above process. This paper describes the progress in the fabrication process for attaining better transmission characteristics and future aspects of this process.
Specific characteristics obtained in this process are: reduction in the transmission loss of fibers by the optimal material composition and dehydration technique, the realization of less than 1 ppb of OH content, a bandwidth that now exceeds 6 GHz-km at 1.3 µm, which was attained through the analytical studies of the profile formation mechanism and the controlling of the deposition condition, and the production of long low-loss graded-index fibers.
Low EPD and High Avalanche Multiplication of Lattice-Mismatched In0.52Ga0.48As on InP Substrate
Authors: Takeda Yoshikazu , Sasaki Akio
Published: March 2014

The etch pit density (EPD) of In1-x
Ga
x
As was found to be lowest at the composition of x\cong0.48 where the lattice was mismatched with the substrate, InP, at room temperature. Electron concentration was achieved as low as 3.8×1014cm-3, and avalanche multiplication was obtained as high as 88 in the mesa-diode of In0.52Ga0.48As on InP.
Integration of a Laser Diode and a Twin FET
Authors: Matsueda Hideaki , Fukuzawa Tadashi , Kuroda Takao , Nakamura Michiharu
Published: March 2014

Monolithic integration of a double heterostructure laser diode and field effect transistors, all of GaAs/GaAlAs, involving only planar type fabrication processes is demonstrated. The ICs are fabricated using liquid phase epitaxy, and lift-off. The functions of normally-on type Schottky gate FETs and a Fabry-Perot type infra-red laser diode are successfully matched, to realize high speed modulation with high extinction ratio and no pattern effect. Moreover, activation of the laser by positively pulsed electric signals on gates is demonstrated utilizing an auto-bias of the ICs. The rise time of the pulsed response is about 0.4 ns, suggestive of GHz operation.
In-Line Holographic Lenses of High Numerical Aperture
Authors: Kojima Chiaki , Miyahara Kosuke , Hasegawa Kayoko , Otobe Takashi , Ooki Hiroshi
Published: March 2014

In-line holographic lenses of numerical aperture of 0.4 and 0.55 were successfully fabricated for the purpose of the application to an optical disk player with a He-Ne laser. They were recorded at 6471 Å in the methylene-blue sensitized dichromated gelatin film of 15 µm in thickness. The special design of the optical recording system and the careful processing of the recording materials were required. The evaluations of the modulation transfer function, the focused beam profile, the average diffraction efficiency and the stability test were performed. Bragg and Raman Nath diffractions occurred in the hologram were also investigated to explain the observed results.
LPE Growth and Photoluminescence of In1-xGaxP1-yASy, on GaAs
Authors: Suzuki Akira , Kyuragi Hakaru , Matsumura Shigeo , Matsunami Hiroyuki
Published: March 2014

Lattice-matched In1-x
Ga
x
P1-y
AS
y
, layers (x∼0.51, y∼0.03) have been grown on (100) GaAs by the supercooling LPE method. Mirror-like layers of 2–10 µm in thickness were obtained under lattice-match conditions at the growth temperature of 785–790°C, with an initial supercooling of 10–15°C, a cooling rate of 0.2°C/min, and a growth time of 10–30min. Photoluminescence of undoped n-layers showed band-edge emissions. Temperature dependence of the peak half-width agreed with the theoretical value of 1.8 k
T. The band gap determined from the peak photonenergy varied as 1.987-(7.28×10-4
T
2)/(T+344) eV. Photoluminescence of Zn-doped p-layers showed the band-edge peak and another emission peak due to the recombination through Zn acceptors.
Low-Threshold-Voltage AC Thin-Film Electroluminescent Device
Authors: Okamoto Kenji , Nasu Yasuhiro , Okuyama Masanori , Hamakawa Yoshihiro
Published: March 2014

Thin-film electroluminescent (EL) devices having low-threshold-voltages less than 50 volts have been developed utilizing ferroelectric insulating layers. Ferroelectric PbTiO3 and PLT layers having a dielectric constant of 100–200 and a breakdown strength of 0.5–1.5×106 V/cm have been employed as insulating layers. Typical threshold voltages of 60 volts for the PbTiO3 film and 45 volts for the PLT film obtained are approximately four times smaller than that of the conventional EL devices. Typical brightness and power conversion efficiency are measured to be 300 fL at 60 volts and 3×10-3 W/W, respectively. The very slight change in the threshold voltage during an initial ageing process is found to be less than 10 volts, which is about one order of magnitude smaller than that of the conventional EL devices. Technical data on the relation between the device performances and the device structure are presented and discussed.
(Invited) Ion Implantation into a Cr-Doped Semi-Insulating GaAs Substrate
Authors: Nishi Hidetoshi , Okamura Shigeru , Inada Tsuguo , Hashimoto Hisao
Published: March 2014

In this paper, we present the current technical state of ion implantation into a Cr-doped semi-insulating GaAs substrate. It is shown that low dose implantation to form n layer is relatively well understood and already established as a controlled doping technique. Problems encountered in high dose implantation for n+ layer formation are discussed. Emphasis is on the redistribution behavior of Cr during the post-implantation annealing in Cr-doped semi-insulating substrate with the objective to correlate it with the electrical properties of low-dose implanted layer or to illuminate the complicated situation of high-dose implanted layer.
Planar GaAs IC's Using Multiple Localized Ion-Implantation
Authors: Kusakawa Hirotsugu , Suyama Katsuhiko , Okamura Shigeru , Fukuta Masumi
Published: March 2014

The family of planar GaAs IC's has been developed by using a multiple localized ion-implantation technique. In order to show advantages of the multiple localized ion-implantation technique, 5-stage ring oscillators and binary frequency dividers have been fabricated using both multiple ion-implantation and ordinary single ion-implantation.
A maximum counting frequency of 2.2 GHz for the divider was obtained from IC's fabricated using the multiple ion-implantation technique; on the other hand, 1.1 GHz was obtained when single ion-implantation was used. A 4-bit arithmetic and logic unit (ALU) has been fabricated to examine the adaptability of this planar ion-implantation technique to the GaAs LSI fabrication process.
(Invited) Wafer Bow and Warpage
Authors: Takasu Shin'Ichiro , Otsuka Hideo , Yoshihiro Naotsugu , Oku Taiji
Published: March 2014

Initial Si wafer bow origin, and the relation between initial wafer bow and heat cycled wafer warpage were studied systematically through looking at crystal growth, from wafering process to heat cycle conditions. Initial bow and heat cycled warpages were studied from the view point of their sign and type, and their state was characterized as being of a non-elastic, elastic or plastic wafer deformation nature. Several instruments were used including a newly developed one. Initial wafer bow is seen to originate from initial slicing blade rim bending. Heat cycled warpage a fixed wafer buckling form, caused by dislocation generation and multiplication. Wafer warpage is thus seen to be affected by residual backside damage, oxygen concentration, and oxygen precipitation.
Novel Deposition Technique of a-Si: H –Silane Glow Discharge in Magnetic Field–
Authors: Hamasaki Toshihiko , Hirose Masataka , Kurata Hiroyuki , Taniguchi Mitsuhiro , Osaka Yukio
Published: March 2014

Optical emission spectra from the glow discharge of silane have been studied as a function of magnetic field applied to the plasma column. The result has revealed that the magnetic field remarkably affects not only the decomposition kinetics but also the structural properties of the resulting films. Further, the crystallization of phosphorus doped Si: H films is found to occur at a temperature below 200°C, under the deposition conditions of a low flow rate of silane and the presence of the magnetic field.
Improvement of the Open Circuit Voltage of Amorphous Silicon Solar Cells
Authors: Kaneko Setsuo , Saito Takeshi
Published: March 2014

a-Si(H) films have been produced in a large diameter chamber, in order to eliminate the influence of the chamber walls on the discharge, using an electrodeless inductive coupled RF glow discharge system and p-i-n a-Si(H) solar cells have been fabricated.
Open circuit voltage, as high as 0.845 V of a 5% efficiency cell, has been obtained. The 0.875 V maximum open circuit voltage has been obtained by optimizing the film deposition condition. Dark I-V and I
sc-V
oc characteristics have also been examined to evaluate the non-doped layer.
Amorphous SiGe: H for High Performance Solar Cells
Authors: Nakamura Genshiro , Sato Kazuhiko , Yukimoto Yoshinori , Shirahata Kiyoshi , Murahashi Toshiaki , Fujiwara Kenzo
Published: March 2014

A preliminary study has been carried out on electrical and optical properties of amorphous silicon-germanium mixed films (a-SiGe: H) deposited by a glow discharge plasma reaction. As a germanium content in the film increases, an optical absorption coefficient increases and an optical gap energy E
gopt. decreases. Growth rate of a-SiGe: H films increases with the germanium content in the film and reaches to the value for pure a-Ge: H films about 3 times larger than that of a pure a-Si: H film.
Film properties were examined by dark- and photoconductivity, MOS FET transistor characteristics, and photoluminescence. Photoconductivity and carrier mobilities decreases drastically when the mole ratio GeH4/(GeH4+SiH4) exceeds 25%.
Solar cells of various structures using a-SiGe: H and a-Si: H films were fabricated and compared their photovoltaic properties with that of a simple p-i-n type a-Si: H solar cell. Tandem structure with a-Si: H p-i-n and a-SiGe: H p-i-n cells shows a broadened spectral response at long wave length region and an open circuit voltage of 1.13 V, about twice of a single cell.
Fabrication and Properties of Diffused Solar Cells Using Solar-Grade Silicon Prepared by a Fluidized-Bed Reactor
Authors: Matsubara Sunao , Warabisako Terunori , Kuroda Ekyo , Saitoh Tadashi , Tokuyama Takashi , Enomoto Yoshihiro , Kaneko Kiyoji , Hasegawa Niichiro
Published: March 2014

New solar-grade silicon materials for low cost solar cells are prepared by the hydrogen reduction of chlorosilane gases in a fluidized-bed reactor. Diffused cells are fabricated from 2-inch pulled crystals made from the materials. A high conversion efficiency of 11.3% is obtained from the silicon materials prepared using SiCl4 gas. Diffused cells are also fabricated from purified SiHCl3 gas to investigate the performance of the fluidized-bed reactor, and a maximum conversion efficiency of 13.3 % is obtained. Inhomogeneities in the solar cells are revealed by characterizing laser-beam induced current images and photoresponse variation with illumination intensity. The solar-grade silicon materials are highly promising due to their higher cell performance and lower power consumption in material preparation.
Electrophotographic Properties of RF Glow Discharge-Produced Amorphous Si: H Film
Authors: Yamamoto Nobuyuki , Nakayama Yoshikazu , Wakita Kazuki , Nakano Masao , Kawamura Takao
Published: March 2014

Amorphous silicon film with extremely high dark resistivity, 1013–1014 ohm-cm, at room temperature is prepared for the first time by glow discharge decomposition of SiH4 with suitable doping by B2H6 and a slight content of oxygen. The a-Si: H film exhibits an excellent photoconductive sensitivity in visible wavelength range. Room temperature electron and hole drift mobilities are found to be almost the same in a-Si: H film deposited at 200°C of the substrate temperature and 10-3 B2H6/SiH4 doping gas ratio. These unique properties of a-Si: H films are utilized for bi-chargable monolayer electrophotographic photoreceptor, and positive and negative reproduced images have been firstly demonstrated by utilizing a-Si: H deposited drum.
(Invited) Thermal Nitridation of Silicon in Advanced LSI Processing
Authors: Ito Takashi , Ishikawa Hajime , Fukukawa Yukio
Published: March 2014

Very thin silicon nitride films, thinner than 100 Å, are grown directly on silicon surfaces by thermal nitridation with highly purified ammonia gas. The growth conditions and film stoichiometry have been found to be greatly improved using RF activated gas. The film is dense enough to prohibit impurity diffusion and provides a good interface with silicon. The thermal nitridation process has been applied to fabrications of various LSI devices including very narrow field oxides, low voltage alterable EAROM cells and very thin nitride gate IGFETs. These applications demonstrate that the new process has notable potential in LSI processing.
New Type of Nb Microbridges
Authors: Gamo Kenji , Arimoto Kazutami , Namba Susumu
Published: March 2014

Fabrication procedure using microfabrication technology and DC characteristics of new type of Nb microbridges are presented. The bridges have a threedimensional rotationally symmetric structure which connects two Nb planes separated by a thin SiO2 film through a small pinhole in the SiO2 film. The bridges exhibit no hysteresis in the current-voltage characteristics and the critical current varied weakly with a temperature. Two-junction SQUID's composed of the present bridges show a periodic dependence of the critical current (I
c) on an applied magnetic field at a temperature where I
c almost saturates with a temperature. These are important improvement over one or two-dimensional microbridges.
Nb Weak Links with Three Dimensional Structure
Authors: Tazo Yasuo , Uehara Singo
Published: March 2014

Nb weak links with three dimensional structure were fabricated and tested. A well controlled short length constriction, which is an essential requirement for good Josephson operation, was realized by employing selective anodic oxidation technique. Static and rf characteristics at various temperatures were studied for links with constriction length of 50 nm and constriction diameter of from 0.3 µm to 2.0 µm. The Josephson operation temperature range, as checked by the rf irradiation, was rather wide (from lower than 3.6K to 8.2K, for the smallest diameter links) and showed slight dependence on the constriction diameter.
(Invited) Silicon Graphoepitaxy
Authors: Geis Michael W. , Antoniadis Dimitri A. , Silversmith Donald J. , Mountain Robert W. , Smith Henry I.
Published: March 2014

Silicon graphoepitaxy has been achieved using a strip-heater oven and a sample configuration consisting of a relief grating in an SiO2 substrate, a deposited amorphous silicon film, and a deposited SiO2 overlayer or “cap”. The resulting films are free of cracks and superior in crystallographic orientation and surface smoothness to graphoepitaxial films produced by laser crystallization. Enhancement mode, n-channel, insulated polysilicon gate field effect transistors were fabricated and gave electron surface mobilities in the range 300–460 cm2/V sec at a boron doping of 1016 cm-3. An SiO2 cap, either intentionally deposited or produced by laser crystallization in the presence of oxygen, was found to be necessary for Si graphoepitaxy. We attribute this effect to shear stresses produced by the SiO2 cap during crystallization.
(Invited) A SIPOS-Si Heterojunction Transistor
Authors: Matsushita Takeshi , Hayashi Hisao , Oh-Uchi Norikazu , Yamoto Hisayoshi
Published: March 2014

SIPOS (Semi-Insulating Polycrystalline Silicon) which is used as a surface passivation film has wider energy gap than Si. SIPOS doped heavily with phosphorus or boron has been used as the emitter material of a heterojunction transistor with the base and collector made of Si. An npn SIPOS-Si heterojunction transistor, showing 50 times the current gain of an npn silicon homojunction transistor with the same base Gummel number, has been realized by high-temperature treatments in nitrogen and low-temperature annealing in hydrogen or forming gas. A pnp heterojunction transistor has also been developed and the current gain is about 5 times as large as that of a pnp homojunction one.
Photovoltaic Effect in Monoclinic ZnP2
Authors: Ito Kentaro , Matsuura Yoshihiro , Nakazawa Tatsuo , Takenouchi Hidemi
Published: March 2014

Heterojunction diodes consisting of n type In2O3 film and p type monoclinic ZnP2 single crystal were formed. Spectral response of monoclinic ZnP2 was measured on these diodes using polarized monochromatic light. At wavelengths around 0.76 µm, the response for the electric vector of plane polarized light parallel to the c-axis was considerably larger than that for the light polarized perpendicular to c. The anisotropy of the response corresponds to an intense dichroism observed in the absorption spectrum of monoclinic ZnP2. The overall response observed within the 0.35-0.86 µm range matches with the solar spectrum.
Growth and Evaluation of n-CdS/n-InP/p-InP Heteroface Solar Cell
Authors: Yoshikawa Akihiko , Yamaga Shigeki , Kasai Haruo
Published: March 2014

Fabrication and electrical and optical characteristics of an n-CdS/n-InP/p-InP heteroface solar cell are described. The cell was fabricated by two growth steps; i.e., first, a thin n-InP layer was grown on a p-InP substrate by a conventional LPE technique, successively a thin n-CdS layer was grown on the n-InP layer by the close-spaced technique. It is shown that the photoresponse of an n-InP/p-InP homojunction cell is remarkably improved by applying a CdS layer on the n-InP, because the surface recombination velocity on the n-InP reduces after a CdS growth. Furthermore, the reverse saturation current and the built-in voltage of the InP homojunction are also improved after a CdS growth.
The conversion efficiency of the heteroface solar cell with no AR coating was 10.4% under AM2 condition. The lower observed efficiency than that expected theoretically is attributed to a “poor” electrical characteristic of the n-InP/p-InP homojunction.
Amorphous SixSe1-x–SnO2 Thin Film Photovoltaic Devices
Authors: Matsushita Tatsuhiko , Okuda Masahiro , Suzuki Akio , Naito Hiroyoshi , Nakau Tanehiro
Published: March 2014

Measurements of electrical and optical properties have been made on Si
x
Se1-x
amorphous thin films in the composition range from x=0.05 to 0.2. It is shown how the photovoltaic effect for the system of metal electrode–amorphous Si
x
Se1-x
film–SnO2 layer can be enhanced by the forming process. For the system of x=0.1, the conversion efficiency of about 1% was obtained at room temperature.
Effect of Fluorine on the Photovoltaic Properties of Amorphous Silicon Prepared by DC Glow Discharge
Authors: Nishihata Kazuhiro , Komori Kōichirō , Konagai Makoto , Takahashi Kiyoshi
Published: March 2014

Amorphous Si–F–H films were prepared by DC glow discharge in an atmosphere of SiF4+H2. The electrical and optical properties have been described. Infrared spectra of amorphous Si–F–H have been studied for various deposition pressures. In the n-type doping characteristics, the maximum conductivity obtained is 10.0 (Ω cm)-1 with the addition of 500 vppm PH3. The Schottky barrier a · Si–F–H solar cell shows an efficiency of 3.5% under AM1, 100 mW/cm2 insolation.
Dispersive Transport in Hydrogenated a-Si Prepared by rf Sputtering
Authors: Shirafuji Junji , Kim Gi Il , Sawadsaringkarn Montri , Inuishi Yoshio
Published: March 2014

Time-of-flight measurement of photo-excited carriers has been carried out in hydrogenated a-Si deposited by rf sputtering method. Both electrons and holes show highly dispersive transport. The electron drift mobility near room temperature ranges from 5×10-3 to 4×10-5 cm2/V · s, much lower than that of GD samples, and the activation energy is about 0.3 eV. The value of the hole mobility is comparable with that in GD specimens, but its activation energy is about 0.2 eV which is about half of that observed in GD a-Si.
Photoconductive Decay in Amorphous Silicon Films
Authors: Matsumoto Nobuo , Kagawa Toshiaki , Motosugi George , Kumabe Kenji
Published: March 2014

The photoconductive current behaviors were measured for amorphous silicon films prepared by plasma decomposition and sputtering. The decays becomes faster for shorter and stronger excitation pulse and the slow components of the decays are independent of them and behave as τ-0.5. The results can be interpreted using a model in which lifetimes of excess carriers are distributed in wide range. It becomes clear that the distribution function G(τ) is consisted of two main components, fast (τ<τ0) and slow (τ>τ0) relaxation processes. In the plasma decomposition sample τ0 is 1 µisec and in the sputtered sample τ0 is 0.1 µsec.
Interpretation of Characteristics in a-Si:H Solar Cells
Authors: Uchida Y. , Sakai H. , Nishiura M.
Published: March 2014

Current versus voltage characteristics in an illuminated a-Si:H solar cell which shows conversion efficiency of 4.3% (cell area: 1.0 cm2) are interpreted by assuming a simplified junction model and a distribution of the density of states in the band gap.
Since the width of the depletion region relates to this distribution, a depletion width (W) versus bias voltage (V) relation can be calculated from this distribution. Also, another W-V relation is obtained from light-generated current data on the basis of a few assumptions.
These two different estimations of the W-V relation excellently agree when one assumes a hyperbolic distribution of the density of states in the band gap which is symmetric with respect to the middle of the energy band gap and has a density of mid-gap states of 8.3×1015 (cm3 eV)-1. This value is comparable to the minimum density of states in the a-Si:F:H reported by W. Czubatyj et al.
Fabrication and Properties of Silicon Solar Cells Using Squarely Shaped Crystals
Authors: Kuroda Ekyo , Matsubara Sunao , Saitoh Tadashi , Tokuyama Takashi
Published: March 2014

Square single crystal silicon ingots with 3-inch sides are grown by producing uniform melt temperature distribution in the crucible. The growth of square ingots is described in a model where supercooling is present at the growth interface, and where growth rates vary for different faces. A relatively high conversion efficiency of 12–13% is obtained from square solar cells. Inhomogeneities in the solar cells are revealed by studying laser-beam induced current images and crystal defect density distribution. The packing density in modules increases up to the 0.93–0.95 level. As a result, modular efficiency also increases by 20%, compared with when using circular wafers.
Junction and Bulk Region Characteristics of the Laser Annealed Si Solar Cells
Authors: Usami Akira , Nishioka Hiroshi
Published: March 2014

The photovoltaic characteristics of the Q-switched and normal-switched laser annealed Si solar cells are described and compared with those of furnace annealed cells. Implantation was performed with 2×1014 B+, BF2
+ and P+ ions/cm2 at 80 keV and 100 keV. The efficiency and open circuit voltage (V
oc) of the furnace annealed (FA) cell (800°C) are greater than those of the laser annealed (LA) cells. All cells have no A.R. coating. A efficiency of 6.7% is obtained for the B+ implanted p+/n cell with laser energy density of 1.5 J/cm2. As the junction characteristic, the values of τd (lifetime near the junction) are measured from the decay curve of V
oc. The values of diffusion length (L) in the bulk region for the LA and FA (700°–900°C) cells are about 150 µm and 50 µm, respectively. And the values of τd are comparable for both cells. In the laser annealed cells, the values of τd depend on the laser energy density, while those of L do not and keep the values for starting materials.
Fundamental Properties of MIS Solar Cells Using Mg-p Si System
Authors: Matsuura Hideharu , Nishino Shigehiro , Matsunami Hiroyuki
Published: March 2014

Existence of an inversion layer at the surface of Si in an MIS diode using Mg-p Si system is confirmed by the analysis of C
-2-V characteristics, and charges in the inversion layer are estimated. This diode is thought to behave like a p-n junction diode, since minority carrier current is dominant in I-V characteristics. Effects of oxidation time on the C
-2-V and I-V characteristics are studied. Photovoltaic properties of this inversion type MIS diode are measured.
Efficiency Increase of Solar Cells Operated in Dielectric Liquid
Authors: Ugumori Tadaki , Ikeya Motoji
Published: March 2014

Photocurrent and electrical characteristics are investigated for photo cells operated in liquids. Photocurrent increases with increase in the permanent electric moment of molecules in liquid. This effect is considered to be due to adsorption of polarizable molecules which reduce carrier recombination at the surface of photo cells.
Recent Development in Measuring Techniques of Ultrasonic Velocity and Absorption
Authors: Wada Yasaku
Published: March 2014

Methods for measuring ultrasonic velocity and absorption are classified into six: pulsed ultrasonic wave technique (§2), Bragg reflection method (§3), Brillouin scattering method (§4), reverberation method (§5), resonance method (§6), and variable path interferometer (§7). Basic principles and recent developments of each method are briefly surveyed.
2.944 MHz Bandpass Ceramic Filter for Direct-to-Line FDM Carrier System
Authors: Inoue Takeshi , Takahashi Sadayuki
Published: March 2014

The 2.944 MHz ceramic bandpass filter for direct-to-line FDM carrier system is examined. The filter is designed with 5th order passband Chebyshev characteristics. It is composed of five trapped energy piezoelectric ceramic strip resonators and nine ceramic capacitors. The stopband attenuation is more than 80 dB and the passband ripple is ±0.1 dB. Temperature coefficient of the center frequency is 10 ppm/°C and its aging rate is below 0.01%/decade. The filter size is reduced to 1/5 that of the usual LC filter.
Characteristics of ZnO/Si Monolithic SAW Convolver with MIS-Transistor Structure
Authors: Matsumoto Kazuhiko , Moriizumi Toyosaka , Yasuda Tsutomu
Published: March 2014

The characteristics of the ZnO/Si monolithic SAW convolver with MIS-Transistor structure have been investigated. The convolution output of the present convolver is controlled by the combination of the dc junction bias and the dc gate bias. It has been found that the nonlinearity caused by the carrier flow in the surface channel can be used to generate convolution output when all the junctions are biased with the same voltage. When the junctions are biased in the same way as in a MIS Transistor, the quadratic characteristics of the drain saturation current vs. the gate bias give rise to effective convolution output.
High Rate Deposition of Thick Piezoelectric ZnO and AlN Films Using a New Magnetron Sputtering Technique
Authors: Hata Tomonobu , Takeda Fumio , Morimoto Osamu , Noda Etsuji , Hada Toshio
Published: March 2014

ZnO and AlN films were prepared on glass substrates with a new reactive magnetron sputtering technique using a metal target. Highly oriented ZnO films (c-axis orientation) were fabricated on the glass substrates. Resistivities of the films were 106–109 Ω cm for ZnO and 109–1011 Ω cm for AlN. An electromechanical coupling constant of thick ZnO films (∼30 µm) was obtained by measuring a frequency response of transducer impedance near the fundamental resonance frequency of the interdigital electrode. For AlN, the c-axis orientation from substrate normal to parallel can be controlled by adding H2 gas to N2 gas.
Low Temperature Growth of Piezoelectric Films by RF Reactive Planar Magnetron Sputtering
Authors: Shiosaki Tadashi , Yamamoto Takashi , Oda Takafumi , Harada Kazushige , Kawabata Akira
Published: March 2014

Piezoelectric films of ZnO, AlN and KLN have been fabricated by rf planar magnetron sputtering. A single-drystalline AlN film has been grown epitaxially onto a basal plane sapphire substrate, and a c-axis oriented AlN film has also been grown on a glass or metal-film substrate at substrate temperatures as low at 50°C to 500°C. Because of this low substrate temperature, AlN films have become available for the first time to bulk wave transducers, SAW transducers with the IDT's between AlN films and substrates, SAW transducers on low melting point material, and piezoelectric resonators
separated from their substrates.
Acoustic Drying
Authors: Seya Koichiro , Otsuka Tetsuro
Published: March 2014

The study described in this paper consists of two parts, (1) an investigation of some drying factors which are influenced by high intensity audio frequency range, and (2) an investigation of some methods of applying the high intensity macrosonics range to the drying process.
Drying factors investigated included: the effect of the position of material to be dried in the standing wave field, the effect of particle velocity of sound upon the drying rate and the critical moisture content, and the effect of sound frequency.
The introduction of macrosonics increased the drying rate under all the conditions. The drying rate was found to be substantially increased when the material was positioned at the sound pressure node of the standing wave field.
Estimation of Characteristics of an Ultrasonic Piezoelectric Transducer with Voltage Transfer Gain
Authors: Kojima Tadashi
Published: March 2014

For estimation of the system-independent characteristics of an ultrasonic piezoelectric transducer in a pulse echo system, voltage transfer gain (VTG) is introduced, which is related to the transfer function between the input voltage of the transmitting transducer and the open circuit output voltage of the receiving transducer.
As the VTG represents the frequency characteristics of a transducer itself, the impulse response of a transducer can be easily calculated from the VTG characteristics with the inverse Fourier transformation. Absolute sensitivities of a transducer can also be calculated from both its VTG and input impedance. A typical design example of a 2.5 MHz transducer is discussed through the VTG method.
Acoustoelastic Stress-Measurement in Rolled Materials
Authors: Okada Kenichi
Published: March 2014

A new ultrasonic method is proposed for plane-stress determination in materials with slight orthotropy. This method is, in principle, based on the stress-acoustic relations previously proposed by the author, and utilizes an ultrasonic reflection technique, in which a reference specimen without stress is used together with a specimen to be measured. Equations for stress determination are given in terms of the quantities measured by this technique. Experiments were made on an aluminum plate 4 mm thick under uniaxial tension and the stress-acoustic coefficients appearing in the equations were obtained.
Optimum Ultrasonic Imaging System Using ARMA Processing
Authors: Sato Takuso , Yokota Takayoshi , Ikeda Osamu
Published: March 2014

Aiming at ultrasonic image reconstruction with as high fidelity as possible even from data available in a restricted observing aperture, a new image reconstruction processing based on the autoregressive moving-average (ARMA) model is proposed. The wave field on the object is assumed to be spatially incoherent and the coherence function on the aperture is detected. The image is reconstructed by estimating the power spectrum from the coherence function using ARMA processing. The principle, formulation, algorithm, some results of computer simulation, and basic experimental results are given.
Holographic Sonar 3D Underwater Ultrasonic Imaging
Authors: Sato Tomomasa
Published: March 2014

This paper describes the three-dimensional underwater ultrasonic imaging method. This “Holographic Sonar Imaging Method” combines the technique of sonar and that of acoustical holography. A phase modulating ultrasound using one period of a poly-phase orthogonal sequence is transmitted to the target. After the reflected ultrasound received by a heterodyne circuit of receivers is digitized and memorized, a 3D image is reconstructed by pulse compression and aperture synthesis calculations. The feasibility of this imaging method is presented by computer simulations.
Acoustic Properties of Hedoro Sediment
Authors: Kaya Akio , Tsuchiya Akira , Nishimura Minoru
Published: March 2014

To measure the density and thickness of a soft mud-like sediment (hedoro) layer by underwater ultrasonic pulse reflection method in situ, the relations between acoustical and physical factors concerned with sound reflection are discussed through measurements made in the laboratory. The results, that hedoro is considered as a 3-phase suspension, are applied to the calculation of bottom loss at various frequencies assuming a half-space or a multi-layered bottom model. A multi-layered model is available for estimation of loss at a frequency lower than 500 kHz in this study. At higher frequency, losses of both models show a good agreement.
On the Dispersion of Dolphins by Underwater Ultrasonic Waves
Authors: Hatakeyama Yoshimi , Ishii Ken , Maniwa Yoshinobu
Published: March 2014

Dolphins which come into Japanese waters eat or drive away many useful fish, thereby causing damage to the fishing industry. Since dolphins have excellent auditory capability, it was believed that artificial sounds might be effective in dispersing them. Therefore nine devices generating ultrasounds were manufactured and experiments were conducted in an aquarium pool and near partition nets at sea. The results showed that mechanically beating sounds, 24 kHz pulse, false echolocation clicks and sounds produced by a marine transponder were effective in dispersing the dolphins.
Frequency Spectrum of Acoustic Domain Caused by Variable Rise-Time Pulse
Authors: Tokunaga Yoshiaki , Hata Tomonobu , Hada Toshio
Published: March 2014

This paper is concerned with the behavior of acoustic domain in CdS with use of a variable rise-time of applied pulse. For a rise-time pulse slower than 6 µs, amplified fluxes are from thermal phonons. The peak and width of the flux distributions can be well explained by the small-signal theory. Signal shapes by Brillouin scattering become a trapezoid when the shock is relaxed. The lattice attenuation measured by the ultrasonic injection technique is proportional to the square of acoustic frequency (0.8 GHz to 2 GHz)
Characteristics of Multilayered Thin-Film Optical Tunable Separators Using Surface Acoustic Waves
Authors: Goto Nobuo , Miyazaki Yasumitsu , Akao Yasuo
Published: March 2014

New type optical tunable separators consisting of multilayered thin-film optical waveguides are studied. The coupling strength and coupling length can be controlled by surface acoustic waves. For this coupler, amorphous Nb2O5, Ta2O5 and ZnS film waveguides are fabricated on a substrate, Y-cut LiNbO3, by R.F. sputtering method. Tunable and wavelength-selective properties, that are important factors for active wave separators and tunable optical filters in multi-wavelength optical communication systems, are discussed with analysis of propagation properties of surface acoustic waves in film guides.
Changes of Zero-Crossing Slopes of a Finite-Amplitude Noise Propagating in a Tube
Authors: Watanabe Yoshiaki , Urabe Yasumasa
Published: March 2014

The propagation of a finite-amplitude noise was measured and the slope of zero crossing was regarded as a nonlinear parameter. The slopes become uniform with the increase of the propagation distance although they have various slopes at the source point. It is considered that the nonlinear effects, which are the nonlinear dissipation and the increase of propagation velocity, tighten the waveform and the large shocks sweep up the small irregularities. Therefore these effects make the slope uniform.
Measurement of Acoustic Power Radiating from Linear Array Transducer Using He–Ne Laser Light
Authors: Fukaya Kuniaki , Yano Tsutomu , Fukumoto Akira
Published: March 2014

The absolute acoustic power radiated from a linear array transducer for diagnostic ultrasound equipment has been determined using the integrated acousto-optic method. The acoustic power obtained by this method agrees fairly well with that calculated from the equivalent circuit method. The merits of this measuring technique are non-invasive measurement, ability to determine the absolute value and the possibility of measurements of the uniformity of the array element and the ultrasound beam profile.
High Speed Measurement of Ultrasonic Velocity Changes
Authors: Matsuda Takashi
Published: March 2014

A method has been developed for high speed measurement of ultrasonic velocity changes. The measurement of velocity change is obtained by phase comparison between an echo pulse and a reference carrier signal within a several echo oscillation for change faster than a few microseconds, and by the time-to-amplitude conversion method for change slower than the repetition rate of rf pulse.
A Technique for Measuring Phase Velocities of Surface Acoustic Waves Using Comb Filters
Authors: Hirabayashi Makoto
Published: March 2014

A technique for measuring velocities of SAWs has been developed. The technique utilizes a comb filter, i.e., a filter consisting of a uniform transducer and a transducer with a wide central space. A new accurate equation for obtaining velocities from the amplitude-frequency responses of comb filters has been derived. Velocities on 128°-rotated Y-cut X-propagating lithium niobate free or covered with an aluminum layer 110 nm thick were measured at 22°C. The velocities on the free and metallized surfaces were 3991 m/s and 3880 m/s, respectively, which agree with calculated values. The relative error of the technique was ±0.11%.
Visualization of Three-Dimensional Ultrasonic Wave Fronts Using Holographic Interferometry
Authors: Oshida Yoshihiro , Iwata Koichi , Nagata Ryo , Ueda Masahiro
Published: March 2014

A new method to visualize wave fronts of a 3-D ultrasonic wave in a transparent medium is proposed. It employs holographic interferometry with phase-modulated reference beam. The wave field is illuminated by a sheet-like light and the light scattered in the medium is recorded in a hologram. The reconstructed image displays wave fronts of the ultrasound on the light sheet. The experiments are carried out for an ultrasonic wave with frequency 200 kHz and 1 MHz, and prove the validity of the method. This method is considered applicable for an ultrasonic wave with frequency up to about 10 MHz.
Amplitude Weighted Metal Strip Reflective Array Compressors
Authors: Kitano Toshihiko , Nishikawa Katuhiko
Published: March 2014

Amplitude weighted metal strip reflective array compressors (RAC's) have been developed in which the reflection coefficient of the arrays is adjusted by varying the strip width. This structure has an advantage that the reflectors and the interdigital transducers can be fabricated in a single photolithographic step. Linear and non-linear 30 MHz FM RAC's, whose time-bandwidth (TB) products are 60 and 48, respectively, are fabricated on Bi12GeO20 substrates. Time sidelobe levels of the compressed pulse are less than -27 dB in linear FM case and -28 dB in non-linear FM case. The resulting metal strip RAC's have been proved to be adequate for practical use.
Realization of Miniature SAW Resonators Having High Quality Factor
Authors: Uno Takehiko , Abe Hiroshi , Miyamoto Nobuhide , Jumonji Hiromichi
Published: March 2014

A new SAW resonator design method to reduce resonator size is proposed. The main points of the design are: (1) optimization of transducer-reflector period ratio, in order to adjust the transducer center frequency (f
T) to the reflector center frequency (f
R), and (2) optimization of the transducer-reflector separation so as to create a satisfactory resonance condition at f
R.
Small size resonators with groove arrays were designed by the new method. Groove gratings were formed by reactive sputter etching, and miniature SAW resonators of 6 mm length were realized, with high Q value above 2×104 at 145 MHz.
Temperature-Stable Electromechanical Channel Filter with Temperature-Compensation Torsional Mode Transducer
Authors: Yano Takeshi , Kanazawa Seiichiro , Futami Takehiro , Hayashi Tetsuo
Published: March 2014

The paper presents a method for the design of excellent temperature characteristic electromechanical filters1,2) based on iterative approximation techniques. Elements of a filter are decided in order to minimize the temperature changes in filter characteristic. This paper also includes the 128 kHz torsional mode pole electromechanical channel filter without temperature-compensation capacitor by using a new kind of transducer. It is shown that the filter passband attenuation ripples satisfy the C.C.I.T.T 1/20 standard in a 0°C to 65°C temperature range.
Piezoelectric Polymer Film Transducer for Detection of Acoustic Emission
Authors: Onoe Morio , Yamada Hiroaki , Tomikawa Yoshiro
Published: March 2014

Experimental results connected with an application of a piezoelectric polymer film to an acoustic emission sensor are presented. The keynotes investigated through the experiments are following:
(1) A piezoelectric polymer film, can be used to excite and detect surface acoustic waves like an acoustic emission signal or not.
(2) Relative sensitivity of detection as a function of the diameter of a piezoelectric polymer probe.
(3) Relative sensitivity to layer numbers of a piezoelectric polymer film.
(4) Frequency characteristic of its polymer probe.
Experimental results indicate sufficient possibility of an application of a polymer film to an AE sensor.
PTC Behavior of Semiconductive Ceramics under Reduced Atmosphere
Authors: Igarashi Hideji , Hayakawa Shoji , Okazaki Kiyoshi
Published: March 2014

Changes in PTC behavior of several kinds of semiconductive BaTiO3 ceramics by heat-treatments in 10-5 Torr and in air at temperatures up to 500°C were measured. When an AC field and/or heat-treatments were applied in vacuum to a PTC material, the PTC jump was markedly decreased by 2 to 4 orders of magnitude. When reduced samples with a small PTC jump were heat-treated in O2 atmosphere at temperatures of 1100 to 1300°C, the PTC jump was gradually increased with increasing heat-treating temperature, approaching to the original characteristics of normally sintered materials. The experimental results were explained by the diffusion of oxygen ions through grain boundaries.
Properties of the Large-Capacitance Multilayer Ceramic Capacitor
Authors: Shimada Yuzo , Utsumi Kazuaki , Yonezawa Masatomo , Takamizawa Hideo
Published: March 2014

Electrical properties of the large-capacitance multilayer ceramic capacitor made of the ceramics of Pb(Fe2/3W1/3)O3–Pb(Fe1/2Nb1/2)O3 system were studied. The ceramics are sintered at 900°C in air, and therefore, it is possible to use Ag–Pd alloy as the internal electrode. The size of the capacitor with capacitance of 400 µF is fairly small. Dissipation factor is extremely small (0.6%) under the D.C. voltage bias in wide frequency range. Insulation resistance is more than 6000 M Ω µF. Impedance at high frequency band is small compared with those of other electrolytic capacitors with the same capacitance. Electrical properties are hardly changed in lifetime test.
High-Dielectric Constant Ceramics for Base Metal Monolithic Capacitors
Authors: Sakabe Yukio , Minai Kiichi , Wakino Kikuo
Published: March 2014

In order to make the monolithic ceramic capacitors with a base metal internal electrode, the ceramics of {(Ba1-x
Ca
x
)O}
m
{(Ti1-y
Zr
y
)O2} compositions were investigaed, where 0.02≦x≦0.22, 0<y≦0.20 and 1.005≦m≦1.030. These ceramic materials are sintered in an atmosphere of low oxygen to yield a high resistivity (1012 Ω-cm), a high dielectric constant (7,000∼9,000), and a low dissipation factor of less than 2.5%. The monolithic capacitors of these ceramics with nickel electrode are as reliable as those with precious metal electode.
Deviation of Dielectric Properties in Magnesium Titanate Ceramics
Authors: Sato Takuro , Miyamoto Ryoichi , Fukasawa Atsushi
Published: March 2014

Extremely low loss and high permittivity magnesium titanate (MgTiO3) ceramics has been developed as a medium in the composition of miniaturized microwave filters.
This dielectric ceramics is characterized by the facts that the molar composition of major component materials, MgO and TiO2, is a little deviated from the stoichiometric ratio and that a 3rd component material, CaO, is added for compensation of temperature characteristics.
The permittivity (ε

r
), unloaded Q (Q

u
) and temperature coefficients of resonator frequency (T.C(f)) of this material are estimated to be ε

r
=20, Q

u
=9000 at 6.3 GHz and T.C(f)=0±2 ppm/°C.
K3Li2Nb5O15 and Pb2KNb5O15 Tungsten-Bronze Films for SAW Devices
Authors: Adachi Masatoshi , Kumagawa Katsuhiko , Shiosaki Tadashi , Kawabata Akira
Published: March 2014

Characteristics of SAW properties of tungsten-bronze layered structures of (K3Li2Nb5O15)/(substrate) and (Pb2KNb5O15)/(substrate) combinations have been calculated. Hetero-epitaxial growth of these tungsten bronze films have been also described. KLN single-crystal films have been successfully grown with good epitaxy onto KBN and sapphire substrates by the sputtering technique. The SAW propagation on a KLN film has been observed in a layered structure of (KLN)/(sapphire).
Electromechanical Properties of Piezoelectric Ceramics in the PLZT-PZN System
Authors: Nomura Shoichiro , Kaneta Kumiko , Kuwata Jun , Uchino Kenji
Published: March 2014

Piezoelectric ceramics with the chemical formula Pb1-x
La
x
[(Zr1-y
Ti
y
)1-z
(Zn1/3Nb2/3)
z
]1-x/4O3 (x=0.01–0.06, y=0.3–0.6, z=0.1), which are solid solutions composed of PLZT and PZN (Pb(Zn1/3Nb2/3)O3), have been prepared by hot-pressing at 1150°C, and the dielectric and electromechanical properties have been measured. In these materials the rhombohedral-tetragonal morphotropic phase boundary is located in the range of y=0.40–0.43, where the electromechanical coupling factor k
33 exceeds 70%. The k
eff coupling factor for the thickness mode of a plank-shaped bar also reaches nearly as high as 70% in this range. There exists a proportionality between the dielectric and the mechanical losses in the Mn-doped ceramics.
Liquid Phase Sintering of Grain-Oriented Ferroelectric Ceramics in the Bismuth Layer Structure Oxides
Authors: Takenaka Tadashi , Sakata Koichiro
Published: March 2014

The influence of a low melting second phase added to the grain-oriented ferroelectric ceramics with bismuth layer structure on their densification, forging behavior, grain orientation and electrical properties is investigated by using the hot-forging method combined with liquid phase sintering.
PbBi2Nb2O9 and Bi4Ti3O12 as host materials; Pb5Ge3O11, PbO and Bi2O3 as liquid phase agents are selected. The presence of liquid phase produces a good effect on hot-forging in PbBi2Nb2O9+Pb5Ge3O11 system. The PbO content ranging from 1 to 3 wt% in PbBi2Nb2O9+PbO system is most effective, and k
33 of 15.4% is obtained. On the other hand, liquid phases in Bi4Ti3O12 ceramics have little effect on their densification and forging behavior.
Mechanical Strength of Several Kinds of Piezoelectric Ceramics
Authors: Tashiro Shinjiro , Igarashi Hideji , Okazaki Kiyoshi
Published: March 2014

Several kinds of piezoelectric samples were prepared for the experiments on the mechanical strength. By adding an appropriate additives, the bend strength of BaTiO3 ceramics was greatly increased. In the grain oriented (Pb0.8Sr0.2)Bi2Nb2O9 ceramics, a considerable strength anisotropy was found. In a random oriented sample, the thermally diffused impurities injected by vapor phase diffusion of CuO into the grain boundaries increased somewhat the bend strength. The K

l
c
measurement using micro-indentation technique was applied to a hot-pressed pore-free PLZT ceramic sample and the average value was 0.995 MN/m3/2.