bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Growth and Characterization of Amorphous Hydrogenated Silicon
Authors: Hirose Masataka
Published: March 2014

The chemistry of silane decomposition and possible heterogeneous reactions of admolecules responsible for a-Si: H growth are discussed on the basis of the diagnostic of the silane discharge. Along with the plasma diagnostic, wide optical gap (∼2 eV) and photoconductive (ηµτ≃10-4 cm2V-1) a-Si
x
N1-x
: H has been prepared from the glow discharge of a SiH4+NH3 gas mixture. Result of scanning electron microscopy for microcrystalline-like silicon has exhibited the presence of a columnar structure in the film and the structural model consistent with X-ray and IR measurements is proposed. As for electronic characterization of a-Si: H, the acoustic emission due to the nonradiative recombination of photocarriers in the i-layer of the pin junction has, for the first time, been observed and significant correlation between the acoustic signal intensity and the gap states of the i-layer has been demonstrated.
Window Effects of Hydrogenated Amorphous Silicon Carbide in a p-i-n a-Si Solar Cell
Authors: Tawada Yoshihisa , Kondo Masataka , Okamoto Hiroaki , Hamakawa Yoshihiro
Published: March 2014

A good valency electron controllability has been found in hydrogenated amorphous silicon carbide prepared by the plasma decomposition of [SiH4 + CH4] gas mixture. Utilizing this a-SiC: H layer as window in an a-SiC: H/a-Si: H heterojunction structure, effects of a-SiC: H on the photovoltaic performance have been investigated. A series of systematic experimental data of photovoltaic performance with parameters of methane fraction, optical gap to window side material and p-layer thickness are presented. Remarkable improvements in both short circuit current density and open circuit voltage have been seen in an a-SiC:H/a-Si: H heterojunction cell. This experimental fact implies that not only a wide gap window effect but also voltage factor due to potential profile steepened with wide dap a-SiC: H contribute to the photovoltaic performance of the a-SiC: H/a-Si: H heterojunction solar cell. It has been shown that a-SiC: H might be a useful new material for the development of low cost high efficiency solar cells.
(Invited) Fine Focused Ion Beams
Authors: Seliger R. L. , Kubena R. L. , Wang V.
Published: March 2014

The use of a focused ion beam for direct implantation of dopants into a semiconductor substrate results in appreciable simplification in the processing of semiconductor devices. We have demonstrated that liquid metal (LM) field-ionization sources (based upon the electrostatic formation of an emitting cusp of liquid metal) offer the necessary high brightness to make focused ion beam microfabrication feasible. This paper reports upon three developments: (1) the development of eutectic-alloy LM ion sources for the production of boron and arsenic for direct implantation of silicon devices, (2) the fabrication of a FET using a Au–Si beam that was mass separated at the target and (3) the development of a three-lens variable-energy focusing column that incorporates a mass-separator of low aberration.
(Invited) New Materials for Josephson Junction Devices
Authors: Inamura Takahiro , Murakami Toshiaki , Inukai Takashi , Enomoto Youichi , Suzuki Minoru
Published: March 2014

Fabrication processes and superconducting properties of two types of oxide superconductors, perovskite-type BaPb1-x
Bi
x
O3 (BPB) and spinel-type Li1+x
Ti2-x
O4 (LTO), are described. A new concept of Josephson junction device, namely Boundary Layer Josephson Junctions (B.L.J.J.), is introduced. It is shown that both superconductors have a potentiality for Josephson junctions.
Reliability of InGaAsP/InP Buried Heterostructure Lasers
Authors: Mizuishi Ken-ichi , Hirao Motohisa , Tsuji Shinji , Sato Hitoshi , Nakamura Michiharu
Published: March 2014

Degradation modes of InGaAsP/InP buried heterostructure lasers are classified into three types; rapid, saturable, and gradual degradation. The influences of the temperature dependence of threshold current and the carrier leakage through the buried regions on degradation are described. Lasers that can operate cw above 90°C and show only gradual degradation can be expected to have a mean-time-to-failure of more than 107 h at 25°C.
U-Groove Isolation Technology for High Density Bipolar LSI's
Authors: Tamaki Yoichi , Kure Tokuo , Shiba Takeo , Higuchi Hisayuki
Published: March 2014

A new isolation technology for high packing density bipolar LSI's has been developed. This technology is composed of two main processes, U-groove formation and U-groove filling. The U-grooves are formed by anisotropic etching and reactive sputter etching of silicon. The grooves, covered with a composite Si3N4/SiO2 layer, are filled with polysilicon. Surface planarity is achieved by selective etching of the polysilicon. An ECL integrated circuit fabricated using the U-groove isolation (U-Iso) technology exibits a minimum isolation distance of 3 µm, an isolation voltage of 50 V, an isolation capacitance of 0.2 pF, and a propagation delay time, measured by ringoscillator, of 0.3 ns/gate.
Multi-Coloring of Thin-Film Electroluminescent Device
Authors: Suyama Takahiro , Sawara Nobuyuki , Okamoto Kenji , Hamakawa Yoshihiro
Published: March 2014

Green, orange-red, orange, yellow, blue and white light emitting thin-film electroluminescent (EL) devices have been developed by using various rare-earth fluoride luminescence centers. A series of technical data on the relation between device performances and film deposition conditions are presented. The device performances, particularly, brightness and efficiency, much depend on ZnS active layer thickness and the concentration of luminescence centers, while the substrate temperature is not so effectual to obtain high brightness. The brightness of more than 100 foot-Lambert (fL) has been obtained for the devices emitting green (TbF3, ErF3 and HoF3), orange-red (SmF3), yellow (DyF3) and white (PrF3) under 5 kHz sinusoidal excitation. Especially, more than 600 fL is obtained by the TbF3 doped device. Typical efficiencies are 0.15 lm/W for the device doped with TbF3 and 0.03–0.05 lm/W for the devices doped with SmF3, DyF3, PrF3, ErF3 and HoF3.
Threshold Voltage Difference Compensating Sense Amplifier for High Density Dynamic MOS RAMs
Authors: Furuyama Tohru , Saito Shozo , Fujii Shuso
Published: March 2014

A new threshold voltage difference compensating sense amplifier is introduced, and the sensitivity improvement is verified both theoretically and experimentally. In this paper, theoretical calculation is first presented, then results obtained with a test device, which was designed and fabricated to estimate the new sense amplifier by using MoSi2 gate technology, are described. Measured data show good agreement with calculated data. Remarkable sensitivity improvement, in comparison with a conventional sense amplifier, is observed. From these results, the new threshold voltage difference compensating sense amplifier appears to be applicable to VLSI dynamic RAMs.
Soft Error Rate Analysis Model (SERAM) for Dynamic NMOS RAMs
Authors: Aoki Masaaki , Toyabe Toru , Shinoda Takashi , Masuhara Toshiaki , Asai Shojiro , Kawamoto Hiroshi , Mususada Kazumichi
Published: March 2014

Soft Error Rate Analysis Model (SERAM) for dynamic NMOS RAMs is developed. SERAM simulates the three-dimensional diffusion and collection processes of alpha-particle induced carriers for various incidences. To verify SERAM, the frequency of collected charge in one memory cell and soft error rates of 64 K-bit samples were measured. The simulations were in good agreement with the experiments. Memory cell scaling analysis by SERAM shows that if the cell area scales as (1/K)2, the ratio Q

c
/Q
α decreases as (1/K)β, where K>1, β∼0.4 for unsealed voltages, and Q

c
and Q
α are the critical charge and the noise charge, respectively.
Novel High Alpha-Particle-Immunity and High Density d-RAM Cell
Authors: Tsuchiya Toshiaki , Nakajima Shigeru
Published: March 2014

A novel high-alpha-particle-immunity and high-density dynamic RAM cell with readout signal gain is proposed. The cell is composed of an MOSFET for charge transfer, an MOS capacitor for charge storage and a JFET with buried channel under the MOS capacitor. The buried channel is dynamically switched according to whether there is charge-storage or not in the capacitor. The capacitor area can be extremely reduced, because the cell has smaller collection efficiency for charges generated by alpha-particles, and larger permitted value for leakage charges, compared with other cells. Thus, the cell can achieve higher packing-density memories, compared with other cells.
Scaling Down MNOS Nonvolatile Memory Devices
Authors: Yatsuda Yuji , Hagiwara Takaaki , Minami Shin-ichi , Kondo Ryuji , Uchida Ken , Uchiumi Kyotake
Published: March 2014

Scaling down of MNOS nonvolatile memory devices are presented. Knowledge of operating mechanisms of the electrically alterable nonvolatile memory provides guidelines for choosing the proper thickness of the gate insulating films (Si3N4 and SiO2). It is found that writing time of an MNOS device depends on the nitride thickness alone but not on the oxide thickness, while erasing time depends on the thicknesses of both films. A 10-V programmable scaled down MNOS memory device is realized by decreasing nitride thickness from 50 nm to 19.5 nm and keeping oxide thickness almost constant at about 2.1 nm. Experimental devices are shown to be highly reliable, if the Si3N4 is slightly oxidized, resulting in an MONOS structure.
The Effect of CdTe Pattern on the Characteristics of Screen Printed CdS/CdTe Solar Cell
Authors: Matsumoto Hitoshi , Uda Hiroshi , Komatsu Yasumasa , Nakano Akihiko , Ikegami Seiji
Published: March 2014

The influence of the CdTe width on the characteristics of screen printed CdS/CdTe solar cell was studied by making 14 cells whose CdTe widths ranged from 2 to 8 mm on a 5×10 cm2 glass substrate. As the CdTe width decreased, the short-circuit current density of the cell decreased and the fill factor (FF) increased as expected. However, the increase of the FF with the decrease of CdTe width was smaller than the result calculated by assuming the series resistance of a cell determined only by the resistance of CdS film. Therefore, other improvements such as reducing contact resistances between semiconductor films and electrodes may be necessary to get a higher value of FF. The maximum practical efficiency (ηp) was obtained at the CdTe width around 5 mm, so many cells having CdTe width of about 5 mm were produced using 5×10 cm2 glass substrates and the maximum ηp of 5.2% (intrinsic efficiency of 8.5%) was obtained.
Silicon Solar Cells Made by Liquid Phase Epitaxy
Authors: Ito Kentaro , Nakazawa Tatsuo , Masamura Akira
Published: March 2014

Silicon pn junction solar cells with the conversion efficiency up to 10.4% were made by a liquid phase epitaxial technique. Using gallium instead of aluminum as a solvent, p type silicon epitaxial layers with more uniform thickness were obtained on the n type silicon substrates at lower deposition temperatures. It was found that the fill factor of this solar cell was limited by the series resistance of the diode. The cell efficiency can be increased up to 14% without antireflection coatings by reducing the series resistance effect.
GaAs Concentrator Solar Cells Using Aluminum-Cored Printed Circuit Bases
Authors: Sasatani Yukihiro , Iguchi Shin-ichi , Murakami Kazuhito , Hosoda Yoshikado , Motoyoshi Kenya
Published: March 2014

An effective cooling method is essential for GaAs concentrator solar cells operated under highly concentrated sunlight, because the conversion efficiencies of the cells decrease at high temperature.
We fabricated aluminum-cored printed circuit bases which consist of an aluminum core, anodic oxide layer of aluminum, polymer layer such as polyimide, and metal layer. In this paper we report that this aluminum-cored printed circuit base is effective and that on this base a higher conversion efficiency can be obtained than on a conventional alumina ceramic base. Cell conversion efficiencies of 23.9%, 23.7%, and 22.6% were obtained at 96 suns, 186 suns, and 327 suns, respectively, from the GaAs concentrator solar cell mounted on the aluminum-cored printed circuit base.
Characterization of Amorphous Si: H Films Prepared by rf Planar Magnetron Sputtering
Authors: Nagatomo Takao , Moribe Shunji , Usui Masaaki , Omoto Osamu
Published: March 2014

Hydrogenated amorphous silicon films were prepared by rf planar magnetron reactive sputtering. We describe the influence of the preparation parameters on the physical properties and on the hydrogen content in the films. The hydrogen content C
H and the ratio of C
SiH to C
SiH2
are major factors governing the film properties. The a-Si: H films with the high resistivity (7.2×1010∼1.2×1011 Ω·cm) and the high ratio of photo-conductivity to dark-conductivity (σph/σd∼1.4×104) were obtained at the deposition pressure of 3×10-4 Torr and the substrate temperature of 250°C.
Exact Determination of Bulk Gap-State Density in a-Si: H
Authors: Suzuki Tohru , Hirose Masataka , Osaka Yukio
Published: March 2014

The electronic density of bulk gap-states in a-Si: H has been determined by combining field effect technique with capacitance-voltage measurement of the MOS structure. This new method enables us to make simultaneous determination of both bulk gap-state and surface state density distributions. It is demonstrated that the electronic states existing in the a-Si: H/SiO2 interface hardly affects on the accuracy of the gap state density distribution determined either by the field effect technique or by the conventional capacitance-voltage method.
Ultrathin Silicon Solar Cell for Space Application
Authors: Matsutani Toshinobu , Saga Tatsuo , Ueyama Hideyuki , Hagihara Yasufumi , Hirano Taizo , Suzuki Akio
Published: March 2014

Ultrathin silicon (Si) solar cells for space application were fabricated on an experimental basis and the electrical characteristics were investigated for three kinds of cells (Black, BSFR and Conventional cells). Under 135.3 mW/cm2 (AMO) illumination, ultrathin Black cells showed 67.7 mW output, which is equal to 89% output of 280 µm Black cells. The power to mass ratio of bare ultrathin Black cells was 3.6 times high compared with 280 jum thick Black cells. 1 MeV electron irradiation test was carried out to evaluate the radiation resistance. Ultrathin cells showed superior radiation resistance compared with that of 280 µm thick cells, and it was comparable to that of a GaAs solar cell which had been recognized as a radiation resistive cell.
Our experiments suggest that the ultrathin solar cells have high potential to be used for space application.
Characteristics of Schottky Barrier Diodes in P-doped Amorphous Si: H
Authors: Okushi Hideyo , Yamasaki Satoshi , Kawai Hiroshi , Hotta Masahiro , Tanaka Kazunobu
Published: March 2014

Schottky barrier diodes were fabricated using P-doped a-Si: H films for different doping ratio (PH3/SiH4), and their I-V and C-V characteristics have been presented systematically. The effective density of gap states (N
I) deduced from a 1/C
2-V curve increases with an increase in a doping level of P atoms. N
I is strongly correlated with ICTS and PAS data which are more directly associated with a density of gap states.
Properties and Photovoltaic Characteristics of a-SiC: H Film
Authors: Enomoto Keiichi , Nishiwaki Hidenori , Watanabe Kaneo , Nakashima Yukio , Tsuda Shinya , Ohnishi Michitoshi , Kuwano Yukinori
Published: March 2014

a-SiC: H films was prepared from a glow discharge in a mixture of SiH4 and CH4 in a capacitive coupled system with parallel plane electrodes. The fundamental properties of the a-SiC: H films were investigated. Using the a-SiC: H film for window material, Glass/SnO2/p(SiC)-i-n/Al cells were fabricated by the consecutive, separated reaction chamber method. The best conversion efficiency of the cell with a size of 4 mm2 was 8.15%, which is much larger than that prepared by the single reaction chamber method in our laboratory. It seems that one of the main reasons for the difference in the conversion efficiency is the undesirable mixing of carbon in the non-doped a-Si: H layer.
An integrated type Glass/SnO2/p(SiC)-i-n/Al cell with a size of 10 cm×10 cm was also fabricated. The best conversion efficiency was 6.35%.
Comparison of High Energy Proton Radiation Damages on AlGaAs/GaAs and Si Solar Cells
Authors: Yoshida Susumu , Mitsui Kotaro , Oda Takao , Yukimoto Yoshinory
Published: March 2014

We have developed high performance AlGaAs/GaAs solar cells with a conversion efficiency in excess of 18% and high resistance to radiation damage by high energy protons.
Results on radiation hardness of AlGaAs/GaAs solar cells for 5, 10, 15, and 52 MeV proton with fluences up to 5×1012 p/cm2 are presented.
The AlGaAs/GaAs solar cells are superior to Si solar cells for radiation damage of high energy proton capable of penetrating a coverglass.
Distribution of Electrode Elements near Contacts and Junction Layers in Amorphous Silicon Solar Cell
Authors: Fukada Noboru , Imura Takeshi , Hiraki Akio , Tawada Yoshihisa , Tsuge Kazunori , Okamoto Hiroaki , Hamakawa Yoshihiro
Published: March 2014

Auger electron spectroscopy with the ion sputter-etching technique and secondary ion mass spectroscopy have been utilized to investigate the depth distribution of Sn and In, electrode elements, in amorphous silicon layers of the photovoltaic device. The comparison of the depth profiles with the cell performances has indicated that the presence of the reduced state of In in both the p and i-layers affects the solar cell performance, but that of Sn does not. It was also shown that layered structure of In–Sn oxide (ITO)/SnO2 effectively prevents the diffusion of In and accomplishes high cell performances, having the thickness of the SnO2 layer about 200 Å.
Selenium Thin Film Solar Cell
Authors: Ito Hideo , Oka Masayoshi , Ogino Toshio , Takeda Akitsu , Mizushima Yoshihiko
Published: March 2014

A selenium solar cell has been developed. Its maximum efficiency is 2.7% for an AMI light (100 mW/cm2) and 8.0% for a fluorescent lamp light. The cells are fabricated at low temperature using only vacuum evaporation. This results in a low cost device with high production efficiency. Current-voltage characteristics under illumination show that both series and shunt resistances decrease with illumination intensity.
GaP, AlGaAs/GaAs, AlGaAsSb/GaSb Photovoltaic Devices and Characteristics
Authors: Sasaki Akio , Ishio Keisuke , Noda Susumu , Fujita Shigeo
Published: March 2014

Solar cells using GaP, AlGaAs/GaAs, and AlGaAsSb/GaSb p-n junctions for a spectrum-splitting system have been studied to obtain a high conversion efficiency and a high output power. The GaP solar cell with Si3N4 anti-reflection coating exhibited the conversion efficiency η of 7.6% by the spectrum-splitting (0.35 µm<λ<0.50 µm), while η of AlGaAsSb/GaSb solar cell with a window layer of Al0.34Ga0.66As0.013Sb0.987 quaternary alloy was 1.84% even by spectrum-splitting (1.15 µm<λ<1.65 µm). The low conversion efficiency of the AlGaAsSb/GaSb solar cell is due partly to surface leakage current.
p-Ga0.2Al0.8As/p-Ga1-yAlyAs/n-Ga1-yAlyAs Solar Cells
Authors: Masu Kazuya , Konagai Makoto , Nakatsuka Shin-ichi , Takahashi Kiyoshi
Published: March 2014

Device performance of p-Ga0.2Al0.8As/p-Ga1-y
Al
y
As/n-Ga1-y
Al
y
As solar cell (Ga1-y
Al
y
As solar cell) was studied theoretically and experimentally. Theoretical calculations show that the Ga1-y
Al
y
,As solar cell has (1) a higher AM 1 conversion efficiencies than the conventional p-(GaAl)As/p-GaAs/n-GaAs solar cell under sunlight concentration greater than 600 suns and (2) a superior performance in AM 0 condition. The Ga1-y
Al
y
As solar cells were fabricated on GaAs wafers using the usual liquid phase epitaxy method. The observed characteristics measured under the simulated AMI insolation agree well with the predicted performance.
Photoacoustic Signal Induced by Pulse Ruby Laser in CdS
Authors: Kawai Masatoshi , Morimoto Jun , Yoshioka Takeshi , Miyakawa Toru
Published: March 2014

Both oscillatory and non-oscillatory components of PA signals in CdS single crystals excited by a Q-switched ruby laser were observed by PTZ transducer. Longitudinal thickness mode of CdS sample and PTZ transducer were identified through the analysis of the frequencies of the oscillatory components. Two-photon nature of the absorption process is elucidated from the intensity and polarization dependence of the signals. A simple model can reasonably account for the observed wave form and its dependence on intensity and polarization.
Application of Photoacoustic Spectroscopy to Solids
Authors: Ishiguro Takehiko , Tokumoto Hiroshi
Published: March 2014

Photoacoustic spectroscopy is described from the standpoint of its application to solid characterization. Photoacoustic signals from gas-microphone and transducer methods are discussed using simple models with their numerical calculations. The feasibilities of photoacoustic sepctroscopy are argued by citing recent developments in semiconductor characterization.
Discrimination of Defects by the Change of Wave Shape: Reflection at Right-Angle Corner
Authors: Saito Tetsuo , Fujimori Toshiaki , Harumit Kasaburo , Okada Hisao
Published: March 2014

This experiment revealed that when a transverse wave was applied to the corner, the polarity of the reflected wave was inverted at an incident angle of 45°, as compared to a wave reflected from a flat surface. No change of wave shape was observed at the incident angle of 60°; at the incident angle of 70°, the shape change was observed but was not clear. The experiment also confirmed that longitudinal waves were generated at incident angles of 45°, 60° and 70°.
Reflection of Elastic Waves by an Infinitely Long Ribbon Crack (PART II)
Authors: Okada Hisao , Harumi Kasaburo , Watanabe Shigeyoshi
Published: March 2014

By the use of Mathieu functions, reflection of incident plane elastic waves by a cavity ribbon crack in a steel has been computed. Diffraction patterns have been obtained for πd/λ=1 to 12, where d is the width of the ribbon crack, and λL the longitudinal wavelength.
On a Hysteresis Property in Acoustoelastic Effect
Authors: Okada Kenichi
Published: March 2014

Stress-induced ultrasonic birefringence under uniaxial tensile load was measured on a rolled plate of aluminum. Tensile loads were increased repeatedly up to a high stress level to cause plastic deformation. Measurements were carried out on tensile specimens in four different tensile direction (θ=0°, 30°, 60° and 90°) with respect to the rolling direction of the specimen. The ultrasonic birefringence showed a hysteresis effect induced by plastic deformation which depended on the tensile direction and original structural anisotropy.
Underwater Ultrasonic Wave Transducer Using Interdigital Electrodes
Authors: Nomura Tooru , Kikuchi Tsuneo , Moriizumi Toyosaka , Yasuda Tsutomu , Toda Kohji
Published: March 2014

An interdigital transducer (IDT), developed to excite surface acoustic waves, can emit longitudinal waves directly into liquid. The method of obtaining a convergence acoustic beam by designing the pattern of IDT is discussed in this paper. Also shown is that the acoustic reflection image of an object placed in water can be taken using the convergence beam.
Study on Detection of Buried Steel Bar in Concrete with Electromagnetic Impact Driving Method
Authors: Motooka Seiichi , Okujima Motoyoshi
Published: March 2014

The authors devised a new method of detecting the location of a steel bar within concrete from the concrete surface by an electromagnetic impact driving method. Various experiments were performed to test the possibility of detection by this method. The amplitude characteristics of radiated sound from such a bar were also examined. Consequently, it is clear that the electromagnetic impact driving method is useful for detection of the location of a steel bar buried in concrete.
Recent Trends in Nondestructive Ultrasonic Testing
Authors: Onoe Morio
Published: March 2014

Non-destructive testing has been found increasingly useful in on-line inspection, integrity assurance of large structures, maintenance inspection, weld inspection, etc. For the detection of inner defects, radiographic and ultrasonic testings are available, the latter being more versatile, portable and safe than the former. This paper first discusses the main features of ultrasonic testing and then reviews recent trends in its research and development. Quantitative evaluation, a high resolution transducer, calibration, visualization, integrity assurance, automatic inspection, high temperature inspection, and signal and image processing are covered.
Comparison of Optical Fiber Hydrophones
Authors: Takahashi Sumio , Kikuchi Toshiaki
Published: March 2014

The detection of underwater sound with an optical fiber is studied. The experiments are conducted on both the homodyne method and the heterodyne method. A linear relation between pressure and signal output has been obtained. However, the homodyne method is subject to temperature change depending on the environment of the fiber and the signal output fluctuates, while the heterodyne method is insensitive to temperature change and the signal output remains almost constant.
A Surface-Acoustic-Wave Continuously-Variable Delay Device with Two Unidirectional Transducers
Authors: Hirabayashi Makoto
Published: March 2014

A SAW device with a variable group delay over a wide range has been developed. The device utilizes two unidirectional transducers arranged on one side of a uniform transducer. The unidirectional transducers are inversely connected to each other or have complementary structures. The distance between them is 6.4 mm. The group delay varies with the phase difference between the input signals applied to the electrodes of the unidirectional transducers. The variable region of the group delay is more than 2 µs, and the bandwidth is 620 kHz; moreover, the group delay takes negative values.
Group-type Unidirectional Acoustic Surface Wave Filters Using Distance Weighting Techniques
Authors: Yamanouchi Kazuhiko , Meguro Toshiyasu
Published: March 2014

We earlier proposed distance weighting techniques which have better characteristics than apotization techniques. The distance weighting technique works best for reducing weighting and diffraction loss. A group-type of unidirectional transducer also has low loss characteristics. In this paper we investigate a low loss filter combining the distance weighting techniques and group-type unidirectional transducer.
Scattering from the SAW Waveguide with Edge Corrugations
Authors: Shimizu Yasutaka , Miroku Yoshihiko
Published: March 2014

SAW energy radiates to both sides from a SAW waveguide which has rectangular corrugations at one edge. In this paper we present theoretical results of propagation and radiation characteristics of the SAW waveguide with edge corrugations on both sides by the equivalent transmission line approach. Numerical results are shown for thin ribbon waveguide of gold on fused quartz and Δv/v waveguide on YZ-LiNbO3. As a result, it is found that SAW energy radiates toward only one side of the waveguide, if the corrugation size and position are suitably designed.
Vibration Characteristics of Piezoelectric-Ceramic Transducers for Generating High-Frequency Ultrasonic Power
Authors: Hatano Hajime , Sakuma Sadaomi , Oosumi Jun-ichi
Published: March 2014

Vibration characteristics of unbevelled and bevelled thickness-mode Pb(Zr·Ti)O3 ceramic transducers for generating high frequency ultrasonic power were studied by measuring electrical immitance and displacement distributions. A laser heterodyne system was employed for the direct measurements of the vibrations. It was shown that bevelling circular edges of disk transducers was effective in reducing the influences of coupled radial vibrations and improving the characteristics of thickness vibrations.
Ultrasonic Measurements Under Extreme Conditions. Part II. –Measurements under High Pressure
Authors: Hiki Yosio , Kosugi Toshio
Published: March 2014

The meaning and importance of ultrasonic experiments under high pressure were pointed out, and some examples of sound velocity and sound attenuation measurements in solids under hydrostatic pressure were briefly cited. Special emphasis was put on explaining details of our attenuation experiment by a pulse reflection method for a solid in pressurized fluid, and origins of sound losses other than true energy loss in the specimen solid were fully discussed. An experiment to determine the pressure dependence of damping of dislocation motion in crystals was referred as an illustration.
A Review of Progress in Filter Devices and their Future
Authors: Shibayama Kimio
Published: March 2014

This paper presents a review of recent developments in ultrasonic filter devices–magnetostriction, ceramic, mechanical and SAW filters. Special emphasis is given to an analysis of the developmental process of these various devices and speculation of filter devices in the future digital age is also made.
Optical Probing for Detecting Surface Displacement Profile of Ultrasound Vibrations
Authors: Saiga Noriaki , Tanii Kiyoshi , Suzuki Tatsuro
Published: March 2014

In optical probing of a vibration profile of sound in a medical transducer, using a modified Michelson interferometer, a technique for constant sensitivity is described. The method is due to the electronical processing whereby the influence of the optical characteristics of a measuring surface as well as of external vibrations upon the sensitivity is removed. By using the probing system employing the electronical processing unit, a profile of vibrating sound is found with high fidelty.
Mechanically Scanned Acoustic Microscope
Authors: Chubachi Noriyoshi
Published: March 2014

Recent studies performed mainly in the author's laboratory are reviewed regarding the quantitative measurements of acoustic velocities with acoustic microscopes. An interference microscope is described which measures acoustic velocities in thin biological materials. On the other hand, velocities of leaky surface acoustic waves can be measured by an acoustic microscope in a nonscanning operation. The principle of the velocity measurements is described, and a new construction for the acoustic microscope is described in which a linearly focused acoustic beam is introduced to investigate anisotropies of crystals such as Z-cut sapphire and Y-cut LiNbO3.
Piezoelectric Ceramics Used for Thickness Shear Mode and Their Applications
Authors: Takahashi Sadayuki , Yonezawa Masatomo , Inoue Takeshi , Ohta Masaya
Published: March 2014

Solid solution Pb[Zr, Ti, (Mn1/3Sb2/3)]O3 ceramics with small amounts of metal oxides show large electromechanical coupling factors (>0.5), high mechanical Q factors (>1000), small temperature coefficients of frequency constant (<±10 ppm/°C) and low aging rates of frequency constant (<0.01%/time decade) in regard to thickness shear vibration mode. It was confirmed that 1st and 2nd order group PCM timing tank ceramic filters, as well as the direct-to-line FDM bandpass ceramic filter and the channel bank mechanical filter, using thickness shear resonators made of the above ceramics, have sufficiently good performances and stabilities for practical use.
A Hysteresis Curve Tracer Using a Single-Board Microcomputer
Authors: Ishikawa Kenji , Tomoda Waichi , Toyoda Koichi
Published: March 2014

A new type of hysteresis curve tracer using a single-board microcomputer was produced. A complete hysteresis loop of a ferroelectric material can be obtained in 66 ms by applying a sinusoidal electric field for only two cycles. Limited duration of the field application protects specimens from temperature rise and makes it possible to carry out precise measurements near the phase transition point of a ferroelectric material. Also, hard copies of the hysteresis curve can be easily obtained with an X-Y plotter.
Laser Micromachining of a Modified PbTiO3 Ceramics in KOH Water Solution
Authors: Shiosaki Tadashi , Tanizawa Motoaki , Kamei Hidenori , Kawabata Akira
Published: March 2014

The Ar+ laser-enhanced chemical etching of a modified PbTiO3 ceramics is studied. It is shown that 10 mol/lKOH water solution is the best etchant for the ceramics, giving excellent appearances and edge definitions for hole and slot machining. The depth etch rate is as high as 150 µm/s for the hole machining in the first one second irradiation at 1 W output at 514.5 nm wavelength. It is postulated the main etching mechanism is not direct melting, dissolving or vaporizing of the ceramics but removing of the ceramic grains one after another.
A Color Viewfinder Using PLZT Light Shutters and a B/W CRT
Authors: Himuro Masami , Murano Kanji , Nishigaki Susumu , Masatoki Tamiharu , Ohno Katutoshi
Published: March 2014

A new line-sequential color viewfinder has been developed, which is expected to facilitate greatly the viewing and operating of portable color video cameras. Tri-color separation PLZT light shutters are used to convert the black and white image of a 1.5 inch CRT to a color image providing a resolution of 250 TV lines/inch. The shutters, which have a low-power consumption, are switched at high speed by the line-sequential video signals. A high-brightness and fast-decay luminescence phosphor suitable for this application was investigated.
Growth and Properties of Li2B4O7 Single Crystal for SAW Device Applications
Authors: Fukuta Katsuyoshi , Ushizawa Jisaburo , Suzuki Hitoshi , Ebata Yasuo , Matsumura Sadao
Published: March 2014

Large Li2B4O7 single crystals, up to 45 mm in diameter, have been successfully grown along the X- and Z-axis by Czochralski technique. Fundamental phsyical and chemical properties were determined, and basic SAW properties were studied for the various surface orientations and SAW propagation directions from theoretical and experimental points of view. It was found that there were useful substrate orientations for SAW resonators and narrow bandpass SAW filters around the rotated X-cut, Z-propagation, where SAW propagation delay time was a parabolic function of temperature and SAW coupling factor k2 was approximately 1%. When a SAW propagates along the Z-direction on the 28° rotated X-cut substrate, the temperature coefficient of delay time (TCD) is zero at 20°C and the second order TCD is 0.27 ppm/°C2, k2 is 0.8% and SAW velocity vs is 3470 m/s. The bulk wave spurious signal response level is lower by -20 dB than the SAW fundamental response level.
Vibration Mode Analysis of Circular Ring Transducers
Authors: Ueha Sadayuki , Sakuma Sadaomi , Shinada Toru , Mori Eiji
Published: March 2014

To find out analytical solutions of the vibrations in the circular ring transducer, the frequency spectra and vibration velocity distributions ofPb(Zr, Ti)O3 thick rings are measured for various outer diameters. As the results of the measurement and the analysis, the analytical solutions are found out to be nearly coincident with the measured ones and the R, the E and the L vibration modes are shown to exist as in the disk transducer.
The High Frequency Transducer of HIP-Densified Piezoelectric Ceramics
Authors: Takata Mituhiro , Kageyama Keisuke
Published: March 2014

Two types of modified PZT densified by HIP process were prepared. The one (H7C) is rather ductile and can tolerate machining to very thin disk and the other (H7F) has lower dielectric constant for high frequency operation. Using these HIP'ed PZT ceramics, we obtained the ultrasonic transducers of resonance frequency up to 40 MHz. At that range of frequencies the thickness of ceramic disk was less than 40 µm. It was found that the frequency constant of thin disk was held constant to the lowest thickness examined.
A Highly Sensitive Displacing Device Using Piezoelectric Bimorph with Double-Support Structure
Authors: Tanuma Chiaki , Suda Yoshiyuki , Yoshida Seiichi , Yokoyama Katsunori
Published: March 2014

In order to improve displacing devices, new methods for supporting a bimorph element with a double-support structure were investigated. Consideration of bending properties revealed that, when the bimorph element was bent, the cross-sections at both of the bimorph element's ends rotated. A double-support bimorph element with U-shaped metal plates at each end was designed, the result being used. It was found that the displacement for the double-support bimorph with U-shaped metal plates was approximately 4 times larger than the displacement for a conventional double-support bimorph.
A Piezoelectric Single-Plate Bending Vibrator Using Interdigital Electrodes
Authors: Shimizu Hiroshi , Nakamura Kiyoshi , Oyama Shigeru
Published: March 2014

This paper presents an advanced design of the piezoelectric single-plate bending vibrator, in which interdigital electrodes formed in parallel to the plate-length are used for both poling treatment and excitation of vibrations. The dependences of the capacitance ratio of the vibrator on the electrode dimensions and the poling-voltage are clarified. It is demonstrated that the proposed vibrator exhibits the performance superior to the conventional bimorph vibrator.
Amorphous Dielectrics of Li2O-Nb2O5 System
Authors: Maeda Masaki , Kubo Takahiro , Sato Hidetaka , Ikeda Takuro
Published: March 2014

Properties of rapid-quenched glasses of xLi2O·(1-x)Nb2O5 were investigated. Amorphous phase was found in the composition range 0.25<x<0.55. The crystallization temperature depends on the heating-rate and the annealing-time. Dielectric and elastic properties of amorphous ribbons were measured with varying temperature and annealing conditions.
Results were discussed on the basis of a relaxation model.
Electrical Properties of Thin Films of Amorphous ABO3-Type Materials
Authors: Kitabatake Makoto , Mitsuyu Tsuneo , Hirochi Kumiko , Wasa Kiyotaka
Published: March 2014

Thin films of amorphous PbTiO3 and LiNbO3 were prepared by RF-sputtering deposition on cooled substrates and their electrical properties were studied. The amorphous LiNbO3 film showed high dielectric constant (ε>103) in high temperature region for low frequency measurement. The temperature dependence of dielectric constant can be explained by Debye-type dielectric relaxation. The amorphous PbTiO3 film was certified to contain Pb crystallites and exhibit high surface electrical conductivity (σs\gtrsim10 (Ω· cm)-1). This phenomena disappeared after an annealing above 220°C.
ESR Spectrum and Thermal Expansion of Grain Oriented Bi4Ti3O12 Ceramics
Authors: Kato Terumasa
Published: March 2014

The grain orientation of hot forged Bi4Ti3O12 ceramics were measured with ESR spectra and thermal expansion coefficient. It was concluded from ESR spectra that additive manganes ions were substituted on the lattice site, such as B-site in the perovskite-like unite, and the valency of the manganes ions were trivalent. The coefficients of spin hamiltonian were determined that g-value was 2.522, D-value 0.627 cm-1, A-value 0.0075 cm-1. On the thermal expansion measurment, it was shown that c-axis of the crystal was aligned along the hot-forged axis, and a-axis and b-axis were oriented randomly along the radius axis.
Grain-Orientation of Bi4Ti3O12 Ceramics by Cold-Uniaxial Method
Authors: Shoji Kazuo , Uehara Yasuo
Published: March 2014

The purpose of this paper is to investigate processes of grain-orientation in Bi4Ti3O12 ceramics prepared by a cold-uniaxial method used press forging. This method is characterized by utilizing shape anisotropy of ceramic particles prepared by grinding after prefiring. Such particles are aligned by means of the uniaxial pressing process and high alignment of grains in the ceramics can be achieved by grain growth during sintering process. The maximum degree of grain-orientation in the obtained samples reaches 0.76 in terms of the method proposed by Lotgering, which is nearly equal to that obtained by hot-working methods.
Pyroelectricity of Preferably-Oriented Pb5Ge3-xSixO11 Thick Films Prepared by the Printing Technique
Authors: Takahashi Koichiro , Shirasaki Shin-ichi , Takamatsu Keiji , Kobayasm Nobuo , Mitarai Yukuaki , Kakegawa Kazuyuki
Published: March 2014

A printing technique being simple and inexpensive was used for preparing pyroelectric detector chips. Pinhole-free Pb5Ge3-x
Si
x
O11 thick films (30∼40 µm) with preferred orientations of a- and c-planes could be successfully made in the range of x=0∼1.0. It is of much interest that distinguished reorientation occurred even below the melting points. The preferably-oriented films showed a frequency vs. responsivity relation characteristic of pyroelectric sensors, suggesting high possibility to be used as a commercial detector.
Characterization of Dielectric Crystals by SAM and SPAM
Authors: Kojima Seiji
Published: March 2014

Elastic properties of dielectric crystals have been investigated by the scanning acoustic microscope (SAM) and the scanning photo-acoustic microscope (SPAM). Domain walls of a felloelastic of NdP5O14 crystal have been clearly observed by SAM and SPAM.V(z) curves of several dielectric crystals have been measured by the use of the acoustic cylindrical lens in the non-scanning mode of SAM and the velocities of the leaky Rayleigh waves have been determined. The angular dependence of the leaky wave velocities have been determined in ferroelectric β-Gd2(MoO4)3 crystals.
A Loop Tracer for Instantaneous Measurement of Ferroelectric Hysteresis Phenomena
Authors: Yanagisawa Hidenobu , Fukami Tatsuo , Fujii Shinji , Tsuchiya Hidetoshi
Published: March 2014

The paper describes a loop tracer for observing hysteresis phenomena in ferroelectrics; the tracer utilizes recent digital technology and can record the hysteresis phenomena instantaneously. As the operation speed is very fast, it is easy to observe the loop of aged specimens without changing their electrical state, as well as to trace the depolarizing process dynamically when an ac voltage is applied. From the data obtained a new representation for ferroelectric hysteresis curve has been proposed and discussed with special reference to determination of an internal bias field in the materials.
Fracture Mechanics Evaluation of Acoustic Fatigue in Piezoelectric Ceramics
Authors: Niitsuma Hiroaki , Semba Keizo , Chubachi Noriyoshi
Published: March 2014

Acoustic fatigue in a piezoelectric ceramics has been measured by a new method based on the fracture mechanics concept. By using the method, a velocity of the acoustic fatigue crack growth has been measured as a function of stress intensity factor, separating from the crack initiation and final breakdown. The acoustic fatigue crack growth was observed in a narrow range of stress intensity factor K
I between 0.4K
IC and 0.45K
IC, where K
IC is fracture toughness, and the crack velocity was 3.7–8.2×10-13 mm/cycle.
Aerial Ultrasound Source by Stepped Circular Vibrating Plate
Authors: Otsuka Tetsuro , Kamishima Yoshiyuki , Seya Koichiro
Published: March 2014

For the industrial application of aerial ultrasound, a sound source has to generate high intensity ultrasound. As the sound sources developed are rectangular or circular vibrating plates, a dual beam directional pattern is usually obtained. The vibration figure of these plates is flexural so that vibration nodes are produced on them, and the phase of radiated ultrasound from adjoining vibration loops is a counter phase.
In this paper, a height of a half wavelength at the frequency of around 20 kHz of a convex section was put on a circular vibrating plate between vibration nodes. The radiated ultrasound was adjusted to be in phase so that a single beam directional pattern was obtained on the center axis of a radiated field, and higher maximum sound pressure was obtained than that of the circular vibrating plate.
SAW Device Application to Public Telecommunication System in Japan
Authors: Urabe Shuuji , Uno Takahiko , Onuki Kota
Published: March 2014

SAW devices for a public telecommunication system which have been put into practical service are reviewed and the near future SAW device application is presented.
A 400 MHz SAW timing tank for an F-400M optical fiber transmission system and a 145 MHz SAW resonator stabilized voltage-controlled-oscillator for land mobile telephone system are the only two devices now in practical use. But the use of SAW devices is increasing steadily because of their high frequency fundamental mode operation, good reproducibility, and excellent aging characteristic.
Basic Experiments on Synthetic Aperture Ultrasonic Imaging
Authors: Ishii Jun-ichi , Sasaki Souji
Published: March 2014

The application of synthetic aperture ultrasonic imaging technique to nondestructive testing of material is discussed. A prototype synthetic aperture ultrasonic imaging system has been developed to improve the lateral resolution. The diverging beam transducer is moved along the surface and a tomographic image is obtained within one minute. Experiments carried out on steel block specimens verified the capability to reconstruct tomographic images in high lateral resolution.
New SAW Transducers Using Ferroelectric Ceramic Wedge with Planar Shear-Wave Transducer
Authors: Takeuchi Masao , Sato Masahiro , Shimizu Hiroshi
Published: March 2014

A new wedge-type surface acoustic wave (SAW) transducer is proposed in which a bulk-wave transducer and a wedge are unified by forming the planar shear-wave transducer on a slant surface of an unpoled piezoelectric ceramic wedge. It is confirmed by experiments that the proposed transducer has appreciably broad bandwidth and efficient conversion characteristics and can be modified to generate and detect the radial (converging and diverging) SAW's by using a ceramic wedge with a conical surface and fabricating a planar shear-wave transducer on the surface.
Finite-Element Analysis of Discontinuities in an Elastic Plate Waveguide for Lamb Waves and its Applications
Authors: Koshiba Masanori , Karakida Shoji , Morita Hikaru , Suzuki Michio
Published: March 2014

A numerical approach based on the finite-element method is described for the analysis of the discontinuities in an elastic plate waveguide for Lamb waves. The validity of the method is confirmed by comparing the numerical results for the edge resonance phenomenon in a semi-infinite plate with the results of the variational method. Since the present approach is applicable to the frequency range in which the waveguide propagates multimodes, the Rayleigh wave scattering at a step discontinuity is investigated by adequately enlarging the value of the plate thickness.
Radiation Pattern and Coupling Efficiency of Leaky Waveguide
Authors: Shimizu Yasutaka , Shima Mitsuaki
Published: March 2014

It is well known that the maximum coupling efficiency of a surface-acoustic-wave (SAW) coupler employing leaky waves is about 81%. But if the coupling strength is varied appropriately, the coupling efficiency is expected to be higher. In this paper the coupling strength suitable for obtaining higher efficiency is given and is numerically examined. As a result, higher coupling efficiency is obtained. Furthermore, the diffraction of radiant waves was considered and the influence on the coupling efficiency was investigated numerically. The relation between coupling efficiency and diffraction of radiant waves from SAW waveguide was analyzed quantitatively.
Experimental Investigation on Frequency Accuracy of SAW Resonator on LiTaO3 Substrate
Authors: Koshino Masayoshi , Maeda Shigenori , Kurokawa Teruo , Ebata Yasuo
Published: March 2014

Frequency accuracy of a LiTaO3 SAW resonator was investigated experimentally in terms of temperature characteristics, reproducibility and aging drift. The test resonator has a one-port configuration consisting of an 11-finger pair transducer between two grating reflectors, and its frequency is 90 MHz band. Temperature drift is ±540 ppm in the range from 0°C to 60°C. The relative frequency changes in the fabrication process are ±150 ppm for propagation angle deviation of ±0.5deg
, ±320 ppm for aluminum thickness deviation of ±0.05 µm and ±300 ppm for etching ratio of 0.5±0.05. Aging drift is less than -100 ppm after 2000 hours exposure.