bluuebunny/crossref_metadata_2025 huggingface dataset:
Spin-Polarized Scanning Electron Microscope for Analysis of Complicated Magnetic Domain Structures
Authors: Koike Kazuyuki , Matsuyama Hideo , Mitsuoka Katsuya , Hayakawa Kazunobu
Published: November 2005

A previously reported spin-polarized scanning electron microscope has been improved to form a magnetic domain image using any magnetization vector component in the sample surface plane. This apparatus makes it possible to observe the magnetic domain structure in finer contrast. In addition, the magnetization directions in the sample surface can alsobe determined semi-quantitatively by inspecting two images obtained from the mutually orthogonal components of the magnetization vector.
Generation of Slip Dislocations during Czochralski Growth of Semiconductor Crystals Pullen in a <111> Axis
Authors: Kitano Tomohisa , Ono Haruhiko , Matsui Junji
Published: November 2005

Ease of slip dislocation generation during Czochralski growth of <111> semiconductor crystals is considered, based on the calculation of the Schmid factor distribution when a tangetial stress is exerted on the round ingot surface. Only three out of twelve slip systems are dominant for glide motion of the dislocations in <111> single crystals. The Burgers vectors are perpendicular to <111> growth direction, and the glide planes are three equivalently inclined {111} planes rather than the (111) plane perpendicular to the growth direction. The results are in good correspondence to the features of slip dislocation generation observed in actual Czochralski-grown semiconductor crystals.
Rapid Heating Reflow of Phosphosilicate Glass Enhanced by As Ion Implantation
Authors: Furukawa Masakazu , Hara Tohru
Published: November 2005

Reflow of phosphosilicate glass (PSG) layers enhanced by implanting As ions at 150 keV to 1×1017/cm2 was studied by the rapid heating technique (950∼1150°C, 80 s) using a halogen lamp. The stress produced by the implantation is completely removed by a furnace preannealing at 600°C for 30 min prior to the rapid heating. The As ion implantation reduces the reflow temperature by 50∼100°C as compared with unimplanted PSG layers. No degradation is observed in electrical breakdown voltages and reliability tests of Al interconnections using a pressure cooker.
Nonlinear Optical Absorption of InP Doping Superlattice
Authors: Kobayashi Hideki , Yamauchi Yoshiharu , Kawaguchi Hitoshi , Takahei Ken-ichiro
Published: November 2005

Absorption coefficients (α0) of InP doping superlattice are found to show large reduction (Δα) under optical excitation at 77 K. The optical intensity (I) required to produce the same amount of absorption coefficient reduction is at least one order of magnitude smaller than the value reported for GaAs multi quantum well at room temperature. The value of Δα/α0·I remains larger than one fourth of its maximum in the wide wavelength region from 885 nm to 930 nm. The observed changes in absorption spectra show good agreement with calculated results that take the internal Franz-Keldysh effect into account.
Measurement of a Decaying Plasma with Cryogenic Electron Temperature in 4.2 K Helium Gases
Authors: Kimura Tomohiro , Minami Kazuo , Kitamura Hiroshi
Published: November 2005

Production of a non-ideal plasma is attempted in a different way than done previously: we observe a late period of a decaying plasma in helium gas at 4.2 K. Density and electron temperattzre are measured in a single shot of the decaying plasma by detecting the phase in addition to the absolute value of the microwave transmission through a cavity containing the plasma. Density 107–106 cm-3 and electron temperature 55–4.2 K which correspond to the coupling constants 5.6×10-3–0.12 are observed. Excitation and detection of density diffusion waves through the plasma confirm the measured electron temperatures.
Rare Earth Impurity Analysis for Fluoride Glass Optical Fiber by Photoluminescence Measurement
Authors: Ohishi Yasutake , Hattori Hideo
Published: November 2005

Rare earth impurity in a fluoride glass optical fiber is analyzed according to photoluminescence measurement. According to an analysis using Ar-ion laser excitation, Pr3+ impurity content is quantified as 25 ppb in a fluoride glass optical fiber of the current product. Rare earth impurity analysis using photoluminescence measurement on a fiber specimen has sensitivity at least 1000 times higher than that on a bulk specimen. Photoluminescence measurement is effective for analyzing rare earth impurities in fluoride glass optical fibers.
Low-Temperature Growth of GaAs and AlAs-GaAs Quantum-Well Layers by Modified Molecular Beam Epitaxy
Authors: Horikoshi Yoshiji , Kawashima Minoru , Yamaguchi Hiroshi
Published: November 2005

When Ga or Al atoms are evaporated on a clean GaAs surface in an As-free atmosphere, they are quite mobile and migrate very rapidly along the surface even at low temperatures. This characteristic are utilized for growing high-quality GaAs and AlAs layers at very low temperatures by alternately supplying Ga or Al atoms and As4 molecules to the GaAs substrate. Applying this method, GaAs layers and AlAs–GaAs quantum well structures with reasonable photoluminescence characteristics are grown at 200°C and 300°C, respectively.
Lifetime of Resonant State in a Resonant Tunneling System
Authors: Harada Naoki , Kuroda Shigeru
Published: November 2005

Time evolution of an electron wave packet is investigated to estimate the limit to operation speed of resonant tunneling devices. The wave packet localizes in a quantum well for a finite lifetime. The lifetime is related to the energy width of the resonant level due to the uncertainty principle, and is inversely proportional to the tunneling probability of the funnet barrier. When barriers of the quantum well are asymmetric, the lifetime is determined by the barrier that has the higher tunneling probability.
Nondestruetive Characterization of Deep Levels in Semi-Insulating GaAs Wafers Using Microwave Impedance Measurement
Authors: Fujisaki Yoshihisa , Takano Yukio , Ishiba Tsutomu
Published: November 2005

A new technique called microwave DLTS is developed and proven to be a powerful method for the characterization of deep levels in semi-insulating GaAs wafers. Because this new technique is essentially nondestructive and contactless, it is quite suitable for the direct characterization of GaAs wafers for IC fabrication processes.
Using microwave DLTS, density distributions of EL2 in undoped semi-insulating GaAs wafers were measured nondestructively.
Poly–GaAs Thin Film Deposited on Silica Substrate by RF Sputtering and Its Light Transmissional Characteristics
Authors: Tsuji Seiji , Iri Eiji
Published: November 2005

We have deposited polycrystalline GaAs thin film on silica glass by rf-sputtering polycrystalline GaAs target in an atmosphere of As4. The surface of the film is smooth like a mirror. Its growth rate is around 6 µm/h. From X-ray diffraction analysis, it is known that this film is polycrystalline consisting of mostly GaAs <111> oriented crystallites and partly <110> oriented ones. Analysis of film light transmissional characteristics by multichannel spectroscopy has shown that the light absorption edge of this film has red-shifted by 1,500 Å to around 10,200 Å in comparison with the single GaAs crystal absorption edge of 8,700 Å.
Laser Microfluorometer of Intracellular Free Calcium Concentration in a Single Living Cell
Authors: Urabe Hisako , Tsukakoshi Motowo , Sugiyama Takao , Yazaki Yoshio , Kasuya Takahiro
Published: November 2005

A laser microscope fluorometer system was developed to measure calcium ion concentration in individual living cells. Using indo-1 for the Ca2+ indicator and a He–Cd laser for a fluorescence exciter [Ca2+] in individual culture cells was evaluated with spatial resolution of 2 µm at an accuracy of ±10 nM.
Reflection High-Energy Electron Diffraction Oscillations During Molecular Beam Epitaxial Growth of ZnSe on (001)GaAs
Authors: Yao Takafumi , Taneda Hirohito , Funaki Mitsuyoshi
Published: November 2005

Reflection high-energy electron diffraction (RHEED) intensity oscillations during molecular beam epitaxy (MBE) of II-VI compound of ZnSe are observed for the first time. The MBE growth was achieved on (001)GaAs substrate. After an 1-µm thick ZnSe buffer was grown, stable oscillations were observed at around the molecular beam flux ratio of Zn to Se of 1:3. One period of the oscillation corresponds to the growth rate of monomolecular layer. The observation of the oscillatory behaviors of RHEED is discussed in terms of surface morphology as is observed by RHEED.
Profile Controlled Etching for Mo/WSix Double Layers
Authors: Kuriyama Yoichi , Suzuki Masamitsu , Hirayama Masahiro
Published: November 2005

Reactive ion etching for Mo/WSi
x
(x\cong0.6) double layers has been investigated to fabricate a T-shaped gate electrode for self-aligned GaAs MESFETs. CF4+O2, SF6+O2, and SF6+H2 gas mixtures are used as etching gases. The etch rates for Mo and WSi
x
layers are measured as functions of the partial pressures of O2 and H2 gases. A highly anisotropic etching of WSi
x
layer and high etch rate selectivity of WSi
x
to Mo are found for the SF6+O2 mixture and the SF6+H2 mixture, respectively. A T-shaped Mo/WSi
x
gate electrode is obtained by combining these two etching methods.
A New de Electroluminescent Device Using Sintered ZnS:Mn Phosphor-Ceramics
Authors: Minami Tadatsugu , Komano Masakazu , Nanto Hidehito , Takata Shinzo
Published: November 2005

A new de electroluminescent device using sintered ZnS:Mn phosphor ceramics has been proposed. The maximum brightness and luminous efficiency obtained were 7200 nt and 0.56 lm/W, respectively. These factors were strongly dependent on the copper-coating conditions of the ceramics. The applied voltage at onset of light emission can be controtted from 15 V to 200 V by copper-coating conditions. It was found that the excitation process was due to the hot electron impact of Mn impurity.
Rippled Pattern of Image in HVEM Irradiated Nickel
Authors: Sasaki Shigemi , Jitsukawa Shiro , Iwata Tadao , Hishinuma Akimichi
Published: November 2005

Rippled pattern in several lens of nanometer spacing is found in electron irradiated nickel at very narrow temperature range around 420 K by in situ observation with a high voltage electron microscope. The pattern is formed nearly perpendicular to the direction of g-vector, and vanishes with the cessation of irradiation. From a simple consideration based ona theory of diffraction contrast and reaction kinetics of point defects, the origin of the pattern seems to be small unstable dislocation loops of vacancy type located close to the incident surface of electrons.
Influence of Annealing Method on Microscopic One-to-One Correlation between Threshold Voltage of GaAs MESFET and Dislocation
Authors: Egawa Takashi , Sano Yoshiaki , Nakamura Hiroshi , Kaminishi Katsuzo
Published: November 2005

We have investigated the influence of the annealing method on the correlation between dislocations and the threshold voltage (V
th) of metal-semiconductor field-effect transistors fabricated on liquid encapsulated Czochralski grown undoped semi-insulating GaAs substrate. For the annealing under low arsenic pressure, a one-to-one correlation betweenthe V
th and the dislocations is found and the V
th becomes lower within about a 70 µm radius around the clustered dislocations. For the annealing with arsenic overpressure by AsH3 or with plasma chemical vapor deposited SiN
x
cap, the V
th is not affected by the dislocations. These results indicate that the V
th is affected by the distribution of stoichiometry of substrates.
New Bistable Optical Switching Eletnent Utilizing Wound and Unwound States of Ferroelectric Liquid Crystal
Authors: Yoshino Katsumi , Kisio Shin-ichi , Ozaki Masanori , Sakurai Takao , Mikami Naoko , Higuchi Ryo-ichi
Published: November 2005

A new type of bistable optical switching element utilizing differences of the scattering through the cell of ferroelectric liquid crystal in wound and unwound states has been established in 3M2CPOOB, in which both states can be stabilized due to the balance between the forces of the chirality and the wall effect.
Self-Quenching Streamer Transitions Induced by α- and β-Rays in a Gas Counter
Authors: Koori Norihiko , Sakai Hideo , Sakae Takeji , Matoba Masaru , Kumabe Isao
Published: November 2005

Self-quenching streamer transitions induced by α- and β-rays have been compared with that induced by X-rays in a gas counter filled with an argon-isobutane mixture. Conditions of the transition for obliquely incident α- and β-rays have been measured and found to correlate with the inverse of linear density of primary electrons along the alode wire. Effects of ionization tracks on the self-quenching streamer transition are discussed.
Write-Erase Characteristics of Phase Change Optical Recording in Ga–Se–Te Systems
Authors: Rhee Jung Chul , Okuda Masahiro , Matsushita Tatsushiko
Published: November 2005

Reversible optical changes in a thin-film system of parylene/Te
z
(Ga
x
Se1-x
)1-z
film (0.6≤z≤0.9, 0≤x≤0.3)/parylene structure has been studied by measuring the time required to crystalline from the amorphous state (the erasing time) and the number of reversible reflectance changes occurring between amorphous (written) and crystalline (erased) states. For a specimen with a Ga composition of x=0.15, the erasing time is about 1 µs. From a discussion of the Ga–Se–Te phase diagram, it becomes clear that the optimum composition showing write-erase characteristics is obtained at an eutectic point, in which the segregation is not caused and many cycle operations are possible. The SIC (Surface Induced Crystallization) model seems to be suitable for explaining the erasing process in the chalcogenide thin films.
Measurements of Nonlinear Dielectricity in Ferroelectric Polymers
Authors: Furukawa Takeo , Nakajima Kenji , Koizumi Tomoyoshi , Date Munehiro
Published: November 2005

Experimental procedures and exemplifying results are described in relation to a nonlinear dielectric investigation of ferroelectric polymers. The apparatus developed here was used to apply a sinusoidal electric field and to detect fundamental and higher harmonic electric displacements with a 0.01% accuracy by means of digital sampling and Fourier transform techniques. Three types of experiments were made for PVDF. Measurements at relatively low fields determined the nonlinear dielectric constants in that the second-order constant was shown to reflect the polarity of the sample and the third order one was positive being consistent with cooperative dipoles. The ferroelectric hysteresis loops obtained at very high fields were analyzed in terms of the higher-order Fourier coefficients. The use of a double frequency wave determined the field-dependent linear dielectric constants which showed a maximum during polarization reversal.
Modulation Type Pyroelectric IR Detector
Authors: Yokoo Toshiaki , Shibata Kenichi , Takeuchi Kousuke , Tanaka Toshiharu , Kamino Maruo , Nakano Shoichi , Kuwano Yukinori , Tsuji Mahito , Ikeda Masami , Yamada Yasuhiro
Published: November 2005

We have developed a new type of pyroelectric IR detector which contains a sensing part and a solid state chopper with two bimorph vibrators and two slit plates in the same package. This new detector (M-type IR detector) features high reliability, small volume and low electric power consumption compared with conventional pyroelectric IR detectors using a rotating chopper.
The output voltage and noise voltage of the M-type IR detector have been investigated theoretically and experimentally. It was confirmed that a good performance can be achieved in the M-type IR detector by optimizing the relative position of the two slit plates and the aperture diameter of the shield box.
Electrical and Optical Properties of Si Doped GaAs Grown by Molecular Beam Epitaxy on (311) Substrates
Authors: Takamori Takeshi , Fukunaga Toshiaki , Kobayashi Junji , Ishida Koichi , Nakashima Hisao
Published: November 2005

The electrical and optical properties of Si-doped GaAs grown on GaAs (100), (311)A and (311)B substrates by molecular beam epitaxy (MBE) have been studied. A mirror smooth surface is observed for each orientation at low Si atom concentration. Electrical and optical characteristics of the (311)A sample are similar to Si-doped p-type GaAs grown by liquid phase epitaxy, while (311)B samples show almost the same characteristics as (100) samples. Even for a Si atomic concentration up to 1×1020 cm-3, which is too high to keep good surface morphologies of (100) and (311)B samples, excellent morphologies of (311)A samples were obtained. This orientation dependence may be due to different site occupations of Si atoms and surface atom configurations around Si atoms during MBE growth.
Fabrication of Chalcogenide Amorphous Semiconductor Diodes Using Low Temperature Thermal Diffusion Techniques
Authors: Okano Shuichi , Yamakawa Hiroshi , Suzuki Masakuni , Hiraki Akio
Published: November 2005

Chalcogenide amorphous semiconductor diodes were fabricated using low-temperature thermal diffusion techniques. Anomalous diffusion profiles of Cd ions were observed by secondary ion mass spectroscopy. Two opposite potential barriers were formed owing to a peculiar diffusion profile of Cd; thus, the rectifying effects became poor. A high density of vacancies and dislocation-like defects, especially in the surface region, is considered to cause anomalous diffusion profiles of Cd ions.
High-Performance Hydrogenated Amorphous Silicon-Germanium Solar Cells Fabricated by Photochemical Vapor Deposition
Authors: Yamanaka Satoshi , Yoshida Shinichiro , Konagai Makoto , Takahashi Kiyoshi
Published: November 2005

High-quality a-SiGe:H films have been prepared by photochemical vapor deposition (photo-CVD) with a high dilution ratio of H2. Films with a bandgap of 1.55 eV has a photoconductivity of 1.6×10-4 S/cm (AM1, 100 mW/cm2). Solar cells of the p-i-n type were fabricated by applying such high-quality a-SiGe:H films to the i-layer. The performance of a-SiGe:H solar cells has been drastically improved by introducing graded-bandgap layers at the p/i and i/n hetero-interfaces. At present, a conversion efficiency of 8.65% with high collection efficiencies in the long-wavelength region has been achieved with 1.57 eV bandgap material.
Electron Heat Conduction Coefficients at the Temperature Rise Phase and the Internal Disruption during the Sawtooth Oscillation of Tokamak
Authors: Yamauchi Toshihiko , Shoji Teruaki , Yamamoto Shin , Suzuki Norio
Published: November 2005

The electron heat conduction coefficient χeinside theq=1 singular surface during the rise phase and the internal disruption of sawtooth oscillations were estimated from the experimental profiles, on the basis of an equation derived from the diffusion equation. The equation to estimate the central electron heat conduction coefficient χe(0) was obtained from theory and experiment as χe(0)=KrD2/t;rDthe radius ofq=1 surface andtthe period of rise phase or internal disruption phase of sawtooth oscillation. The factorKis associated with their profiles in the rise phase and the internal disruption. It is suggested from a simulation of internal disruptions that the broadened profiles at the top of the sawtooth oscillation lead to the low values of χe.
Improved Microwave Cavity Measurements for the Density and Collision Frequency in Decaying Plasmas
Authors: Minami Kazuo , Mitera Hisamitsu , Takeda Susumu
Published: November 2005

Well known microwave cavity measurements for determining the plasma density n and the collision frequency v of electrons was improved to be applicable in a simple way to decaying plasmas. Previously, two different microwave frequencies have been required to determine both of the plasma prameters. In the present study we analyzed the general properties of a cavity, and propose an improved method to measure, simultaneously, n and v in a decaying plasma by using only one frequency. The principle is that both parameters are determined by detecting the phase in addition to the absolute value of the transmission coefficient through the cavity. Moreover, we derive various formulas that are useful for measuring both parameters under various assumptions. Various experimental demonstrations for our methods are carried out.
SQUID Galvanometer for Measurements of the Quantized Hall Resistance
Authors: Murayama Yasushi , Endo Tadashi , Koyanagi Masao
Published: November 2005

A SQUID galvanometer composed of an rf SQUID magnetometer and a superconducting flux transformer has been developed in order to improve the measurement resolution of the quantized Hall resistance. The equivalent input noise current of the galvanometer obtained is 4.6×10-13 A/√Hz. The measurement uncertainty of the quantized Hall resistance has been reduced to a few parts in 108 or less by the use of the galvanometer and a Josephson potentiometer. The resolution limit of the measurement is the thermal noise of resistors in the circuit.
High Resolution Neutron Powder Diffractometer with a Solid Methane Moderator at Pulsed Spallation Neutron Source
Authors: Watanabe Noboru , Asano Hajime , Iwasa Hirokatsu , Satoh Setsuo , Murata Hideaki , Karahashi Kazuhiro , Tomiyoshi Shoichi , Izumi Fujio , Inoue Kazuhiko
Published: November 2005

A high-resolution neutron powder diffractometer has been constructed at the pulsed spallation neutron facility KENS. The instrument utilizes a narrow pulsed beam of thermal and epithermal neutrons from a solid methane moderator. A high resolution of Δd/d∼3×10-3 has been realized over a wide d range with a good data accumulation rate and with an excellent signal-to-background ratio. An off-line time-focussing method is introduced in order to obtain better statistics. A Rietveld refinement technique with a new profile shape function is briefly described. Some examples of measurements using a unique capability of this instrument are also presented.
Negative Ions and Energy Distribution in a Hydrogen Plasma Device
Authors: Amemiya Hiroshi , Sakamoto Yuichi
Published: November 2005

The production of negative hydrogen ions, H-, has been experimentally studied using a multipole-type hydrogen-plasma device. The dependence of the density of H- on the heater current, the discharge current and the hydrogen gas pressure was investigated by measuring the energy distribution. The density of H- was determined from the height of a sharp peak of the second derivative of the langmuir probe characteristic, which corresponded to the H- current. The optimum value of these parameters could be found for the production of H-. Primary electrons contributed largely to the production of H-, whereas thermal electrons had little effect.
Production of Ion Beam Using Plasma Filament Ion Source
Authors: Yabe Eiji , Fukui Ryota
Published: November 2005

A plasma filament ion source has been developed as a long-lived ion source for use in ion implantation. This ion source uses a primary discharge to serve as an electron source for a second discharge, which is formed into a plasma filament replacing a thermionic metallic filament used in the Freeman-type ion source. The operation is relatively facile and a good beam stability can be obtained. With any combination of a plasma filament of either argon or neon and a feed gas of either fluoride (AsF5, PF5, PF3, or BF3) or hydride (AsH3), the lifetime was found to be more than 90 hours with an extraction voltage of 40 kV and the corresponding ion current density over 20 mA/cm2. This ion source could produce appreciable amounts of As+, B+, P+ and O+ ions, yielding analyzed currents of 10.0, 3.0, 2.6 and 3.0 mA, respectively. This device proved to be eminently suitable for oxygen ion production and also useful for ion implantation incorporated with full cryopumping. Furthermore, the role of the electron temperature of the plasma filament was shown to be of importance in the dissociation and ionization of the feed gas molecules.
Experimental Study of the Mechanism of Skiing Turns. I. An Uphill Turn from Straight Running Downhill
Authors: Sahashi Toshio , Ichino Shoji
Published: November 2005

The aim of the present paper is to show, using a small model ski sliding on a flat sand slope, that by setting a ski on its left/right edge in a straight downhill run that this will lead to a left/rightward turn. The turn is assisted by an accompanying upward flex of the tip section. The result is supported by a field experiment with a real ski on snow.
The Enhanced Electroplating of Nickel by UV-Irradiation before Plating Step
Authors: Ishikawa Yutaka , Nakamichi Ichiro
Published: November 2005

The effect of UV-irradiation before the plating step in the electroplating of nickel has been investigated. A nickel film deposited by electroplating becomes thicker than usual upon UV-irradiation onto the substance before the plating step.
Simultaneous Measurements of Basis Weight and Moisture Content of Sheet Materials by Microwave Cavity
Authors: Nakayama Shigeru
Published: November 2005

In an ordinary measurement, different sensors separately monitor the basis weight (B) and the moisture weight (M) of papers; thus, measurements of the BM weights are not always correct owing to the different measuring parts and times. The purpose of this note is to develop a method for the simultaneous measurements of the BM weights of paper by using a 3 GHz microwave cavity.
Lateral Far-Field Interference Pattern of Buried Heterostructure Lasers
Authors: Junyaprasert Kuntigo , Ogasawara Nagaatsu , Ito Ryoichi , Aiki Kunio
Published: November 2005

Subpeaks in the lateral far-field pattern of buried-heterostructure InGaAsP/InP lasers are shown to be caused by the interference between light scattered at the lateral sidewalls out of the active region and the guided main beam. This is made clear by discriminating the scattered light and the main beam utilizing a screen at the facet. It is demonstrated that the main beam remains to be a fundamental mode and the scattered light intensity is usually 30% or less of the main beam intensity, even for a diode that exhibits a highly complicated far-field pattern.
Ultrahigh Pulsed Magnetic Field Produced by a CO2 Laser
Authors: Daido Hiroyuki , Mima Kunioki , Miki Futoshi , Fujita Masayuki , Kitagawa Yoneyoshi , Nakai Sadao , Yamanaka Chiyoe
Published: November 2005

A method is presented for generating a high magnetic field using a CO2 laser pulse. The magnetic field, current and voltage in a one-turn coil were measured as functions of the gap width, where the high voltage was induced by laser irradiation at a fixed intensity of 1.3 × 1014 W/cm2. These results could be explained on the basis of lateral transport by hot-electron E × B motion and an expansion of the critical density plasma in the gap. The maximum magnetic fields are determined and limited by the filling time of the gap with a critical-density plasma. In order to obtain higher magnetic fields, we tested a cylinder-type one-turn coil attached to the optimized gap. The highest magnetic field observed was 400 T.
Average Bond Lengths and Atom Arrangement in In1-xGaxAs and GaAs1-xPx III-V Ternary Alloy Semiconductors
Authors: Ichimura Masaya , Sasaki Akio
Published: November 2005

Statistics for five different tetrahedra in In1-x
Ga
x
As and GaAs1-x
P
x
III-V ternary alloy semiconductors were derived through a thermodynamical analysis. Every bond length between nearest-neighbour atoms in each tetrahedron was calculated. Then, average bond lengths were obtained theoretically; they agree fairly well with experimental data from the extended X-ray absorption fine structure. Effects of the short-range order in atom arrangement on the average bond lengths were discussed.
Thermodynamical Analyses and Luminescence Properties of Vapor-Grown ZnSxSe1-x
Authors: Goto Hideo , Zhou Jun , Sawaki Nobuhiko , Akasaki Isamu
Published: November 2005

Vapor phase transport analyses are presented regarding the epitaxial growth of ZnS
x
Se1-x
on GaP. It has been predicted from a thermodynamical calculation and experimentally confirmed that the solid composition x can be controlled over a wide range by varying the source and/or the substrate temperature. The photoluminescence of epitaxial layers of ZnS
x
Se1-x
(0.44≤x≤0.92) grown on GaP exhibits a strong edge emission at room temperature, showing that the epitaxial layers are of high quality.
An Automatic Wire-Winding Machine for MWPC's
Authors: Kuze Masahiro , Ishikawa Katsumi , Kishida Takashi , Sai Fuminori , Tsuboyama Toru , Yamamoto Sukeyasu S.
Published: November 2005

A simple and low cost CAMAC controlled automatic wire-winding machine for MWPC's has been designed and built. It is capable of winding wires for MWPC's up to 20 × 20 cm2 with desired wire spacings and tensions. The wire spacing accuracy of less than 1% for 2 mm spacings and the tension uniformity of 3% have been achieved.
Second Harmonic Generation in an AlGaAs Double-Heterostructure Laser
Authors: Ogasawara Nagaatsu , Ito Ryoichi , Rokukawa Hiroyuki , Katsurashima Wataru
Published: November 2005

Second-harmonic radiation emanating from an AlGaAs transverse-mode-stabilized laser diode has been observed under continuous-wave operation at room temperature. The far-field beam width of the second-harmonic radiation has been found to be apprecialy narrower than that of the fundamental laser radiation.
CARS Spectroscopy of SiH4 and Si2H6 in Supersonic Free Jets
Authors: Kawasaki Masahiro , Kawai Eikichi , Sato Hiroyasu , Sugai Kazumi , Hanabusa Mitsugu
Published: November 2005

CARS spectra of the ν1 band of SiH4 and Si2H6 were observed in a supersonic jet expansion and under cell conditions at room temperature. The cooling behavior of rotational and vibrational populations was shown in supersonic expansions. Under cell conditions, the contribution of hot bands was clearly present. The simulation procedures are discussed for the CARS spectra of these molecules.
Light-Induced Effect of a-Si Films Fabricated Using the Super Chamber
Authors: Ohnishi Michitoshi , Tsuda Shinya , Takahama Tsuyoshi , Isomura Masao , Nakashima Yukio , Nakamura Noboru , Nakano Shoichi , Yazaki Takehito , Kuwano Yukinori
Published: November 2005

The light-induced effect of a-Si films with low impurity concentrations fabricated in the super chamber was investigated. It was confirmed that a reduction of impurity reduces the light-induced effect over a range of more than 1018 cm-3 for oxygen. Furthermore, other factors come to have an influence on the light-induced effect in the low-impurity region. We believe that there are at least two types of light-induced defects, one related to impurities, which may be located below the midgap, and one related to structural properties, which may be located around the midgap. For a further reduction of the light-induced degradation in a-Si films, it is necessary to reduce the impurities in a-Si films and to suppress the creation of dangling bonds around the midgap.
Application of Atomic Mutations Included in Nuclear Reactions, 40Ar(γ, p)39Cl(β decay)39Ar, to Surface Study
Authors: Ohkuma Juzo
Published: November 2005

It has been found that the nuclear transformation processes which are initiated by photonuclear reactions can be used for studying the adsorption and chemical reactions taking place on solid surfaces. Chemically reactive 39Cl was produced by irradiating 40Ar with high-energy bremsstrahlung, and its blow was directed onto several material surfaces. The amount of chlorine adsorption was ascertained by detecting its radioactivity. Desorption without heating the adsorber samples inevitably occurred owing to the nuclear decay of 39Cl. The adsorption and desorption rates were compared for several elements. A fast growth of oxide islands on sample surfaces was observed during the adsorption-desorption process.
Transient Characteristics of Luminescence from GaAs/Ga0.6Al0.4As Multi-Quantum-Well Structure under Resonant Excitation
Authors: Miyoshi Tadaki , Aoyagi Yoshinobu , Segawa Yusaburo , Namba Susumu
Published: November 2005

The transient characteristics of photoluminescence from the exciton band in a multi-quantum well have been examined under a resonant excitation condition of the exciton by using a time-correlated single-photon counting method. We have found that the delay, rise and decay times of the luminescence depend on the wavelength of excitation and observation, and that the dependences disappear with increasing temperature from 20 to 50 K. These results could be well explained in terms of exciton relaxation through localized levels created by a fluctuation of the width of the multi-quantum well.
A Self-Consistent Monte Carlo Simulation for Two-Dimensional Electron Transport in MOS Inversion Layer
Authors: Shirahata Masayoshi , Taniguchi Kenji , Hamaguchi Chihiro
Published: November 2005

Hot electron transport in a MOS inversion layer on a (100) silicon surface was analyzed by using a rigorous Monte Carlo method while taking into account changes in subband structures due to electron repopulation. An iterative procedure of the method consisted of a self-consistent calculation of the Schrödinger and Poisson's equations as well as a Monte Carlo calculation for electron scattering. The calculated relative electron population in each subband significantly differed from the results of a conventional Monte Carlo calculation in a tangential electric field higher than 10 kV/cm, above which carrier heating effects greatly influence the subband structures. The calculated electron drift velocity is in reasonable agreement with the experimental data.
Flux-Pinning Effect by Ferromagnetic Overlayer on Superconducting Niobium
Authors: Aoki Ryozo , Habermeier Hans.U.
Published: November 2005

The pinning effect of a ferromagnetic substance on superconducting fluxoids has been investigated. Two kinds of ferromagnetics (mu-metal and γ-hematite (the sound tape) were shaped in thin narrow bands (∼45 µm, t. ×0.3 mm, w) and overlayed on the top surface of a niobium disc (2 mm, dia. ×0.5 mm, t).
A magneto-optical observation was carried out on the sample surface at 4.7 K with an external magnetic field of 0 to 1 kOe; it was demonstrated that the propagation of the flux density distributions from the sample edge was evidently depressed upon crossing the mu-metal band, but hardly effected by the hematite.
The estimated pinning force at 2 × 10-1 dyne/cm of the mu-metal band can be accounted for by the measured magnetization of the band.
Infrared Stimulation of a Zinc Sulfide Phosphor
Authors: Osada Kikusaburo
Published: November 2005

The IR stimulation of a commercial ZnS:Cu, Al phosphor was observed at room temperature within the ranges 1350 to 1050 nm and 715 to 688 nm. The trap depths estimated from the thermoluminescence are in or near the range of the former values. It is concluded from measurements of the peak intensity and the decay of the IR stimulation that the probability for a retrapping of optically released electrons increases with an increase in the number of empty shallow traps.
Electroluminescence and Charge Carrier Transport in Potassium-Doped Anthracene
Authors: Okii Hironori , Ohba Yujiro
Published: November 2005

The increase in the electroluminescence (EL) intensity in potassium-doped anthracene crystals (K-Ant) was investigated in relation to the mechanism of EL. Carrier drift mobilities µe+h and transient EL were measured by the doubly-injected impulse method. The drift mobility of K-Ant along the c'-axis was larger by a factor of 1.5 than in an undoped anthracene single crystal for electric fields larger than 1.9×104V·cm-1. An analysis of the transient EL showed that recombination through recombination centers in K-Ant crystals occurs more efficiently than in anthracene single crystals. These results reveal that the potassium atoms in K-Ant crystals do not act as carrier traps but, rather, act as recombination centers.
Transferred Charge in the Active Layer and EL Device Characteristics of TFEL Cells
Authors: Ono Yoshimasa A. , Kawakami Hideaki , Fuyama Moriaki , Onisawa Kenichi
Published: November 2005

The relationship between transferred charge in the active layer of a thin-film electroluminescent (TFEL) cell and EL device characteristics has been investigated electrically. Making use of a charge density-voltage characteristic measuring system based on a Sawyer-Tower circuit, a general formula for the input power density was found to be given by twice the product of the frequency, the threshold voltage of the active layer, and the transferred-charge density. From this formula, the luminous efficiency could be estimated, once the dependence of the luminance upon the frequency and the transferred charge density was found.
At a frequency smaller than the inverse of twice the luminous decay time, e.g. 500 Hz in the ZnS:Mn case, the luminance was found to be proportional to the product of frequency and transferred charge density. Hence, the luminous efficiency becomes constant with a value 2–2.5 times larger than that for 5 or 1 kHz drive conditions.
Application of Photo-Assisted Etching Technology to Preferential Etching of Si for Dielectrically Isolated Structure
Authors: Ozawa Kiyoshi , Ito Takashi , Ishikawa Hajime
Published: November 2005

A fabrication sequence of a dielectrically isolated structure by field-assisted bonding of oxidized wafer pairs and preferential etch-back process utilizing a photo-assisted etching technology is presented. The etching technique utilizes the high etch selectivity between an epitaxially grown moderate resistivity layer and a low resistivity n-type substrate. The photochemically etched surface is specular and the thickness variations of the epitaxial layer can be controlled to less than ±20 nm across a 3-inch diameter wafer. The process controllability is superior to conventional methods because of the simple etch mechanism. The technique has shown considerable promise for the fabrication of a practical SOI substrate.
A Solid State Electron Detector for the EB60 Electron Beam Lithography System
Authors: Murashita Toru , Shibayama Akinori , Fujinami Minpei
Published: November 2005

This paper discusses the development of a new solid state electron detector (SSD), which is a key component for a high-precision, high-throughput EB direct exposure system, the EB60. The SSD is a low-noise, fast-response detector for a weak input electron beam signal having a nanoampere current and energy of approximately ten kilo electron volts. The SSD has a new metallization structure on the active area for eliminating the effect of incident photons coming from an optical wafer height sensor. For the smallest input signal (15 keV electrons) operation, an SSD with a wide active area of 25 mm2 has a current gain of 2300, a rise time of less than 350 ns and a leakage current of 80 pA; this is negligible to the output signal of a microampere. A long-term stability of a 3% current gain decrease after electron beam bombardment for 1000 hours, and a leakage current of 100 pA after bombardment for 5000 hours have been obtained. A highly accurate, high-speed registration mark detection of 0.02 µm and 50 ms per mark has been achieved through the SSD.
High-Pressure Cell for Neutron Scattering
Authors: Onodera Akifumi , Nakai Yutaka , Kunitomi Nobuhiko , Pringle O. Allan , Smith Harold G. , Nicklow Robert M. , Moon Ralph M. , Amita Fujitsugu , Yamamoto Naoichi , Kawano Shinji , Achiwa Norio , Endoh Yasuo
Published: November 2005

We have developed a high-pressure cell for neutron scattering. The cell uses a barrel-shaped support cylinder made of sintered ceramics. Samples 6 mm in diameter and 10 mm long can be accommodated. The cell is suitable for use at low and high temperatures, after a pressure generated at room temperature is locked. The change of pressure on cooling to cryogenic temperatures is estimated by measuring the lattice parameter of NaCl. Besides the pressure locking technique, continuous pressurization can be achieved at room temperature by using a built-in mini-press while the cell is mounted on a goniometer of neutron spectrometer.
Optimum Toroidal Phasing for Stable Loading of an ICRF Wave in JT-60
Authors: Hamamatsu Kiyotaka , Kishimoto Yasuaki , Fukuyama Atsushi , Itoh Kimitaka , Itoh Sanae I. , Azumi Masafumi
Published: November 2005

The propagation and absorption of the ion cyclotron range of frequencies (ICRF) waves, which are launched by toroidal-phased antennas, were studied in a JT-60 plasma. The second ion cyclotron resonance in a one-dimensional pure hydrogen plasma was considered by solving the kinetic wave equation. The dependence of the loading resistance on the antenna phasing as well as on the plasma parameters was obtained by numerical calculation. A model of a transmission line was introduced in our analysis. The optimum phasing and the plasma parameter region were obtained for a stable loading. Furthermore, it is shown that a combined heating with the neutral beam injection (NBI) makes the stable loading region wider.
Characteristics of Cleaning and Carbonizing Plasmas in TEXTOR
Authors: Amemiya Hiroshi , Ishii Shigeyuki , Oyama Hitoshi , Sakamoto Yuichi , Minagawa Hideki , Satake Tohru , Hashiba Masao , Yamashina Toshiro , Noda Nobuaki , Hori Yoichiro , Akaishi Kenya , Miyahara Akira , Banno Tatsuya , Winter Jörg , Höthker Klaus , Bieger Wolfgang
Published: November 2005

Plasma parameters for discharge cleaning and carbonization in TEXTOR (Torus Experiment on Technology Oriented Research in the Kernforschungsanlage Julich) have been measured with Langmuir probes. In the rf-assisted glow (RG) discharge of hydrogen, at 1.6×10-1 Pa, the plasma density is n
e = 3.0-4.0×108 cm-3, the electron temperature T
e = 10-12 eV, and the space potential V
s≦265 V. In the electron cyclotron resonance (ECR) discharge, at 1.1 × 10-2 Pa, n
e=2.0-2.7×1010 cm-3, T
e=3.5-5.2 eV, and V
s=20 V in the resonance region. The width of this region is about 20 cm. In the carbonization by the RG discharge with an admixture of methane into deuterium at a volume ratio of 33%, at 1.7×10-1 Pa, n
e = 0.9-1.4×109 cm-3, T
e = 2.7-3.3 eV and V
s≦280 V.
The flux of ions and neutral atoms are estimated from measured parameters. In RG(H2), both H+
2 and H are effective for cleaning. In ECR, an appreciable flux of H is obtained, and the H+
2 flux, though reduced by the radial magnetic field, has an effect of cleaning. In RG(CH4/D2), the positive ion flux of the order of 6×1013 cm-2s-1 is responsible for the carbonization.
Photoionization of Residual Gases in Electron Storage Rings
Authors: Miyahara Yoshikazu
Published: November 2005

Production rates of positive ions due to the photoionization of residual gases caused by synchrotron radiation in electron storage rings were estimated numerically. It was found that the production rates of H+
2 and CO+ are about one half that due to the collisions of circulating electrons. The rates are fairly high in the straight section where a multipole wiggler or an undulator is installed.
Electrochromic IrOx Thin Films Formed in Sulfatoiridate (III, IV) Complex Solution by Periodic Reverse Current Electrolysis (PRIROF)
Authors: Yoshino Takako , Baba Nobuyoshi , Arai Kenji
Published: November 2005

Electrochromic thin films of iridium oxide have been obtained by alternative anodic and cathodic polarization of the electroconducting glass (NESA) in a sulfatoiridate complex solution. On both electrodes a transparent, dark-blue deposition was observed. According to the current waveform, it is suggested that the repeated anodic and cathodic polarization acts as coloring and bleaching processes of the electrochemically growing deposit, the electrochromic oxide film gradually thickening on the NESA. The deposits are very adhesive to the substrate NESA. This method offers a simple and economical process for manufacturing iridium oxide films on NESA glasses compared with the already reported method.
Selective Masking Effects of WO3 Resist on Impurity Diffusion and Oxidation in Silicon
Authors: Baba Mamoru , Abe Susumu , Ikeda Toshio
Published: November 2005

Selective masking effects of a WO3 electron resist on phosphorus diffusion and oxidation in silicon at 1000°C are described. Though the diffusion coefficient of phosphorus in the WO3 layer is about twice as large as that in the SiO2 layer, the WO3 resist is useful as a masking film for phosphorus diffusion at elevated temperatures around 1000°C. On the other hand, the masking effect of the WO3 layer on the oxidation of a silicon substrate is insufficient, since the diffusion coefficient of O2 molecules in the WO3 layer is about eight times as large as that in the SiO2 layer.
Direct Determination of Stress Levels in Sputtered Films by means of X-Ray Diffraction Topographic Method
Authors: Nittono Osamu , Sadamoto Yoshihiro , Gong Sheng Kai
Published: November 2005

An X-ray topographic method was effectively used to determine stress values as well as the stress nature of thin sputtered films deposited on silicon single-crystal wafers. This method has a simple mechanism, and the stress values can be determined directly from X-ray topographic images without any knowledge of the elastic constants of films. This technique was applied to a determination of the stress levels in iron films and iron nitride films deposited on Si wafers. An iron film sputtered under a low Ar gas pressure has been found to be in a compressive state, while an iron nitride film is in a tensile state. This technique may serve as a monitor for estimating stress levels in such deposited films as new types of chemical vapor deposition (CVD) and physical vapor deposition (PVD) films whose elastic constants are imprecisely known.
Equilibrium Crystal Shapes on a Flat Substrate
Authors: Uwaha Makio
Published: November 2005

The equilibrium shape of a crystal on a flat substrate is determined by the Wulff-Kaischew construction in which the effective interfacial tension is substituted for the surface tension of anisotropic crystal in the direction of the contact with the substrate. Since the total free energy is proportional to the crystal volume for a given Δµ, the crystal changes its orientation so as to reduce the volume as the interfacial tension changes.
Observation of an Insulator-Metal Transition with Na+-Irradiated Amorphous MoO3 Films
Authors: Koshida Nobuyoshi , Iketsu Yuichi
Published: November 2005

It is shown that the electrical and optical properties of thin amorphous MoO3 films significantly change upon sodium ion irradiation at about 10 kV and that an insulator-metal transition occurs at fluences near 1016 cm-2. These results may be caused either by an electrical activation of the implants or by some compositional change as a result of a sputtering effect.
GaInAsP/InP CBH Surface-Emitting Laser with a Dielectric Multilayer Reflector
Authors: Watanabe Isao , Koyama Fumio , Iga Kenichi
Published: November 2005

The threshold current of a GaInAsP/InP surface-emitting (SE) injection laser has been reduced to 15 mA (CW) at 77 K. The diameter of circular buried mesa was made smaller (∼18 µmφ), and a 5-pair SiO2/TiO2 dielectric multilayer reflector was introduced to a circular buried heterostructure (CBH) SE laser. The threshold exhibited the lowest value ever obtained.
GaAs/AlAs Multi-Quantum-Well Optical Waveguides Fabricated by Disordering Superlattices
Authors: Ohmori Yutaka , Tate Akiyuki , Kobayashi Morio
Published: November 2005

GaAs/AlAs multiquantum well waveguides were fabricated by Zn-diffused disordering of superlattices. The measured propagation loss of the straight waveguide was 1.8 dB/cm at a 1.3 µm wavelength. An S-bend waveguide has shown that bending excess loss can be ignored for S-bend curvatures larger than 3 mm in radius.
Ultraviolet Laser Ablation of a Silicon Wafer
Authors: Kawasaki Masahiro , Sato Hiroyasu , Inoue Gen
Published: November 2005

Pulsed laser irradiation at 248 nm can ablate Si atoms from a Si (100) wafer. The mechanism of this photoablation has been examined by a laser-induced fluorescence analysis of the Si products. The measured Si atoms were shown to leave the wafer surface with an average translational energy of 2.5 kcal/mol. The distribution of the translational energy is well described by a theoretical model for non-cascade ablation processes.