bluuebunny/crossref_metadata_2025 huggingface dataset:
New Manipulator Based on Surface Acoustic Wave Streaming
Authors: Akihiko Sano Akihiko Sano , Yoshikazu Matsui Yoshikazu Matsui , Showko Shiokawa Showko Shiokawa
Published: October 2002

We report a new micromanipulator based on the surface acoustic wave (SAW) streaming. When a small solid object is loaded onto a water droplet placed on a SAW substrate and the SAW is excited, the object can be moved easily and smoothly with the droplet in the SAW propagation direction.
Small steel balls of 0.5 to 4.0 mm in diameter were examined as manipulated samples to be loaded onto a droplet. The experimental results are compared with those of the direct drive method without preloading, by which an object is moved towards an operating interdigital transducer (IDT) in the direction opposite to the SAW propagation direction. It was observed, that the driving efficiency of the present method was sixty times larger than that of the direct drive method. Moreover, a teflon sheet, which is difficult to move by the direct drive method, can be moved with ease by the present method. We conclude that the present method has a high potential for practical use as a micromanipulator.
Measurement of the Temperature Rise at the Welding Surface of Different Metal Specimens Joined by a 15 kHz Ultrasonic Butt Welding System
Authors: Tsujino Jiromaru , Ueoka Tetsugi , Asada Yukihiro , Taniguchi Shinya , Iwamura Yukio
Published: October 2002

The temperature rise at the welding surface of different metal specimens joined by a 15 kHz
ultrasonic butt welding system is studied. The welded zone of the ultrasonic welding is limited to
a very thin area and a clear melted structure cannot be observed and also the temperature rise at
the welding surface cannot obtained by clearly measured. Temperature rises at the welding
surfaces of different metal specimens are measured directly by the thermoelectromotive force
between them, using a system with a small time constant. The temperature rises are measured
using a 15 kHz ultrasonic butt welding with which it is possible to join the welding specimens
directly end to end. Aluminum, copper and steel plates of 6 mm thickness were successfully
joined end to end. The measured temperature rise rate is very high at the initial welding stage
and decreases, or the temperature saturates, as the welding process progresses and the welding
strength increases.
Effects of Electrode Geometry on Breakdown Voltage of a Single-Gap Pseudospark Discharge
Authors: Taguchi Hisashi , Sato Teruyuki , Itagaki Minoru , Watanabe Masayuki , Morikawa Yoshikazu , Abe Yoshihiko , Shimada Tsutomu
Published: October 2002

The breakdown voltage of a single-gap pseudospark discharge device is measured for a wide range of nitrogen gas pressure, p, and various geometrical dimensions of the electrodes, i.e., anode-cathode gap distance, L, diameter of electrode hole, d, thickness of the electrode, t, and depth of the hollow cathode cavity, h. The breakdown voltage V
s is expressed as an empirical scaling relation, V
s=(197/p
3.40
L
3.41){t(L/d)3.25/[t
2(L/d)2+50]1/2}. The breakdown voltage characteristic can be qualitatively explained by the geometrical dependence of the penetrating electric field through electrode holes. The real discharge path length in the pseudospark discharge is estimated.
Relationship between the Harmonic Components and Illuminating Frequency for the Microbubbles: Experimental and Numerical Consideration
Authors: Shinichi Takeuchi Shinichi Takeuchi , Kawan Soetanto Kawan Soetanto , Motoyoshi Okujima Motoyoshi Okujima
Published: October 2002

The nonlinear response of microbubbles has been considered as a basis for ultrasound blood vascular image enhancement system using nonlinear behavior of microbubbles. In this paper, the relationship between the condition of microbubble samples and illuminating conditions of ultrasound for the microbubbles coated with a surfactant membrane are studied experimentally and by numerical simulation. The effect of the number of ultrasound pulse shots, illuminating frequency and size distribution of bubbles are considered, experimentally. To simulate the relationship between the illuminating frequency of ultrasound exposed to the bubbles and the behavior of the harmonic component, a mathematical model, taking into consideration the compressibility of the surrounding liquid around the bubbles and the effect of the coated membrane is proposed.
Monte Carlo Simulation of Normal and Abnormal Glow Discharge Plasmas Using the Limited Weight Probability Method
Authors: Makoto Goto Makoto Goto , Yoshiomi Kondoh Yoshiomi Kondoh
Published: October 2002

A self-consistent Monte Carlo modelling technique has been developed to study normal and abnormal glow discharge plasmas. To simulate nonequilibrium particles, a limited weight probability method is introduced and a fine subslab system is used. These two methods are applied to a DC Ar-like gas discharge simulation. The simulations are performed for conditions corresponding to the experimental voltage and current sets of normal and abnormal glow disharges. The characteristic spatial profiles of plasmas for normal and abnormal glow discharges with high nonequilibrium electron energy distributions are obtained. The increase in the current and the voltage from the normal glow leads to the following: (1) the density peak of the ions rises in the cathode region, (2) the density peak of electrons rises and catches up with that of ions and the peak position occurs closer to the cathode simultaneously; instead of a small increase of plasma density in the bulk plasma region, (3) reversal field strength next to the cathode fall increases and (4) the two groups of the enregy distribution separates into three groups at the cathode fall edge.
Very Rapid Nonscanning Brillouin Spectroscopy Using Fixed Etalons and Multichannel Detectors
Authors: Itoh Shin-ichi
Published: October 2002

To develop very rapid and stable Brillouin spectroscopy, a Fabry-Perot interferometer (FPI) with a solid etalon or air-spaced fixed
etalon and a multichannel detector was constructed. The
fundamental idea is based on the property of angular dispersion of
the FPI. The whole spectrum is acquired at one time, and hence
scanning of FPI is not required. Typical acquisition times are about
1 s with a cw laser and several ms with a pulse laser.
Determination of the Shear Wave Velocity Profile Using Scholte Waves in Marine Sediments
Authors: Kawashima Sayuri , Kimura Masao
Published: October 2002

Scholte waves propagating between seawater and marine sediment exhibit velocity dispersion if the shear wave velocity of the sediment under the seabed surface depends on the depth. Therefore, the velocity dispersion of Scholte waves can be used to determine the shear wave velocity profile of marine sediment. In this study, group velocity dispersion characteristics are derived from data from Scholte waves obtained in Jervis Bay and Hunters Bay, Australia, using a multiple filter method. Shear wave velocity profiles are then obtained from the group velocity dispersion characteristics of Scholte waves using an inversion method.
An Ocean Acoustic Tomography System with a 200 Hz Giant Magnetostrictive Source
Authors: Nakamura Toshiaki , Nakano Iwao , Kaihou Ieharu
Published: October 2002

This paper describes tomography equipment for measuring ocean phenomena in a 1000 km2 area.
A 200 Hz giant magnetostrictive source was developed to increase the transmitting level and
decrease the source size. Five 200 Hz transceiver systems were constructed with these sources.
These systems have surface buoys for real-time data transmission via the INMARSAT-C. Sea
tests of the five transceiver systems were conducted east of the Izu-Ogasawara Trench to observe
the Kuroshio Extension during July and September 1997.
Characterization of ZnInxSey Thin Films as a Buffer Layer for High Efficiency Cu(InGa)Se2 Thin-Film Solar Cells
Authors: Ohtake Yasutoshi , Chaisitsak Sutichai , Yamada Akira , Konagai Makoto
Published: October 2002

The structural, optical and electrical properties of ZnIn
x
Se
y
(ZIS) thin films on Cu(InGa)Se2
(CIGS) thin films and glass substrates were characterized. Polycrystalline ZIS thin films were grown
by the coevaporation method using three constituent elements. We confirmed the formation of
ZnIn2Se4 from the X-ray diffraction patterns of the ZIS thin films on glass substrates. From the
transmittance and reflectance measurements of these films, the bandgap of ZIS is estimated at around
2.0 eV in this study. In addition, the ZIS films on glass substrates show low dark conductivity and
high photosensitivity, which are suitable for the buffer layer in CIGS thin-film solar cells. We also
fabricated the CIGS thin-film solar cells with a ZnO/ZIS/CIGS structure, and investigated the
relationship between the cell performance and the beam intensity ratio of zinc to indium.
A Simple Ohmic-Contact Formation Technology using Phosphine Plasma Treatment for Top-Gate Amorphous-Silicon Thin-Film Transistors
Authors: Ugai Yasuhiro , Yukawa Teizo , Amano Kazuaki , Aoki Shigeo
Published: October 2002

The effects of exposing patterned indium-tin-oxide (ITO) on amorphous
silicon oxide (a-SiO
x
) to a phosphine (PH3) plasma has been investigated.
Phosphorous atoms react with ITO to form InPO
x
and InP, with a much smaller
number being deposited on a-SiO
x
. If amorphous silicon (a-Si) is then
deposited onto these layers by plasma enhanced chemical vapor deposition,
phosphorous atoms from the ITO are incorporated into the a-Si in the region of
the ITO. This effectively dopes the a-Si to form good ohmic contacts between
the ITO and a-Si layers. In contrast, the number of phosphorus atoms
incorporated into a-Si directly above a-SiO
x
is too small to have an effect on
the electrical properties of a-Si. The doping mechanism for the ITO and a-Si is
discussed, and an explanation given as to how these features can be used to
mass produce high performance top-gate a-Si thin film transistors using only
three photomask steps.
Contact Resistance of SnO2 Films Determined by the Transmission Line Model Method
Authors: Kiichi Kamimura Kiichi Kamimura , ZhanHe Wang ZhanHe Wang , Yoshiharu Onuma Yoshiharu Onuma
Published: October 2002

The specific contact resistance of SnO2 thin films was estimated by the transmission line model (TLM) method. The values were on the order of 10-6–10-4 Ωm2. The sample was annealed in N2 atmosphere at 200–650° C. The TLM measurement before and after annealing indicated that annealing was not effective in reducing the contact resistance. The high-temperature annealing resulted in the increase in both the specific contact resistance and the sheet resistance of the SnO2 thin film.
Excitation of Sheath Oscillating Current by Superimposing Pulse Voltage
Authors: Sawa Yoshio , Fujii Syuitsu , Horiike Yasuhiro , Shindo Haruo
Published: October 2002

For an end point detection of etching in ULSI fabrication processes, the behavior of the sheath oscillating current was theoretically and experimentally investigated by superimposing a pulse voltage to the bias . The oscillation of the displacement current in sheath was numerically calculated employing the fluid equations of plasma. The results showed that the excitation of sheath oscillation was possible even in high density plasma of the order of 1012 cm-3. The frequency of the oscillation thus excited depends on both the sheath width of electrode and the plasma density. It is stressed that the frequency measurement provides a new technique for detection of sheath width as well as the end point detection of etching. Experimental measurements of oscillations were also made in an inductively coupled plasma. The frequency of the oscillation thus measured was very consistent with the above calculated.
Electrical Characterization of Ferroelectric Pb(Zr, Ti)O3 Thin Films Deposited on Pt-Coated RuO2 Electrodes
Authors: Jeon Min-Seok , Lee Jae-Bok , Choi Duck-Kyun
Published: October 2002

Ferroelectric Pb(Zr, Ti)O3 [PZT] thin films deposited on Pt-coated RuO2 electrodes are found to have
concurrent advantages in both fatigue and leakage current characteristics. Perovskite phase of PZT having
a random orientation was obtained on as-deposited and Pt-coated RuO2 bottom electrodes and the
crystallinity increased slightly when the PZT films were deposited on Pt-coated RuO2. PZT films with
hillock-free and fine-grained microstructures resulted in all the cases. The PZT films on hybrid electrodes
(Pt/RuO2) showed a typical P–E hysteresis loop. PZT films in all the cases did not exhibit fatigue until
over 1010 switchings regardless of the bottom electrodes. The asymmetric I–V curve of a PZT thin film on
Pt/RuO2 exhibited the Schottky behavior, which indicates that blocking contact is formed at the interface
between PZT films and hybrid electrodes. The leakage current density of the PZT thin films on as-deposited and 30-nm-thick Pt-coated RuO2 at 75 kV/cm was 4.73×10-6 and 9.55×10-7 A/cm2, respectively.
Relation between Molecular Structures of Dichroic Dyes and Their Solubilities in Fluorinated Liquid Crystals
Authors: Naito Katsuyuki , Iwanaga Hiroki
Published: October 2002

A molecular design rule for dichroic dyes with a high solubility in fluorinated liquid
crystals has been investigated. Molecular interactions and a concept of motional segments
proportional to molecular weight were introduced to explain the deviation from an ideal
solution. A semi-empirical equation was obtained: log
C=-20.75 (ΣΔH
f/T - ΣΔS
f)- 0.013(E
h - E
p)+2.32, where C represents a saturated solubility in wt% at T (K). ΣΔH
f (kJ kg-1)
represents the sum of the enthalpies of fusion and of phase-transitions from T to melting
point. ΣΔS
f represents the sum of the entropies. Calculated E
h represents a hydration
energy. E
p is the hydrophobic energy determined from calculated 1-octanol log
P. Log C is
mainly determined by the interaction between dye molecules. Bulky, rigid and asymmetric
structures give a high solubility. Large electrostatic interaction between a dye molecule
and liquid crystal molecules increases solubility.
Fabrication Process of Color Filters Using Pigmented Photoresists
Authors: Kudo Takanori , Nanjo Yuki , Yamaguchi Yuko , Yamaguchi Hidemasa , Kang Wen-Bing , Pawlowski Georg
Published: October 2002

The fabrication process of color filters produced with a series of new pigmented photoresists
(CX513RGB) and their performance are described. The novel resist materials offer excellent
contrast, good film uniformity and a stable shelf life exceeding 6 months, which was achieved by
optimization of the amount and the molecular weight of a proprietary pigment dispersant. The
development conditions of the pigmented resists were found to be influenced by their adhesion to
the substrate materials (glass, chromium oxide and pixels). Dissolution type development was
observed for prebake temperatures below 135°C or when developers with higher tetramethyl
ammonium hydroxide (TMAH) concentrations were used. The desired overcut pattern profiles
were obtained when development times ranged from 60–180 s. CX513RGB resists obey the
“reciprocity law” over 3 mW/cm2 and thus the resist sensitivity is not affected by the irradiation
power generated by conventional mask aligners (15–20 mW/cm2).
Analysis of Horizontal-Vertical Patterning Asymmetry in a Linearly Polarized Deep UV Exposure System
Authors: Lim Chang-Moon , Hyeong-Soo Kim Hyeong-Soo Kim , Ki-Ho Baik Ki-Ho Baik
Published: October 2002

The asymmetric property of horizontal and vertical lines and spaces is investigated using the commercial deep UV scanner which utilizes a polarized illumination source. An approximate aerial image threshold model is used to introduce the quantitative contrast value of the measured horizontal and vertical pattern sizes. The line and space patterns along the horizontal axis, perpendicular to the polarization direction on the mask plane, always shows a higher contrast than that of the vertical axis. The contrast difference becomes greater as the pattern size becomes smaller. In addition, it is observed that the optimum exposure energy of the vertical line and space pattern is smaller than that of the horizontal ones. Finally, the patterning characteristics of the gate lines of the real devices with a 0.20 µ m design rule is investigated according to the orientation of the patterns.
Estimation of Optical Phase Aberrations of Micro-Optics Components by the Irradiance Transport Equation
Authors: Rios Susana , Gato Lazaro , Acosta Eva , Kato Toshio , Iga Kenichi
Published: October 2002

A mathematical method for the recovery of the optical phase by using the transport
intensity equation is proposed. The method, based on phase decomposition of in orthogonal
series expansion, allows us to calculate the least-squares estimation of each mode coefficient
of the phase as a weighted integral over intensity measurements. Experimental results of focal
length and the third and fifth order spherical aberration of planar microlenses are presented.
These results are compared with those of other experimental methods.
A Novel Injection-Molded Precision Plastic Platform for the Passive Alignment of a Polymer Waveguide Film and Optical Fibers
Authors: Tamura Yasuaki , Hikita Makoto , Shuto Yoshito , Amano Michiyuki , Tomaru Satoru , Sato Hirotsugu , Imamura Saburo , Tohno Shun-ichi
Published: October 2002

A newly-designed plastic alignment platform formed by a precise injection molding
technique is proposed for connecting a polymer waveguide film to optical fibers. This platform
consists of a pair of parallel arrayed V-grooves separated by a flat cavity for the polymer
waveguide film. The core positions of the film are strictly determined by using polymer
processing techniques including microlithography. A precisely aligned connection is then
realized simply by placing the polymer waveguide in the mount cavity of the component. This
provides an average connection loss of 0.2 dB/port.
Wavefront Sensor Using a 2-Dimensional Diffraction Grating
Authors: Ohba Hiroshi , Komatsu Shinichi
Published: October 2002

A wavefront sensor that measures the wavefront of a light wave plays an important role in adaptive optics. In this paper, we propose a new wavefront sensor using a 2-dimensional diffraction grating. By this technique, the wavefront can be determined from the measured intensity data of the light passing through the diffraction grating. Using this technique, we measured the wavefront of a spherical wave as well as a light wave distorted by thermal turbulence.
Investigation of Charge Trapping in a SiO2/Si System with a Scanning Capacitance Microscope
Authors: Hideto Tomiye Hideto Tomiye , Takafumi Yao Takafumi Yao
Published: October 2002

The local electrical properties of a SiO2/Si structure is investigated
using a scanning capacitance microscope (SCaM). The sample investigated in
this study was p-type Si with a 10-nm-thick thermal oxide layer. The
capacitance measurement reveals the local variation of capacitance, which
reflects the electrical properties of the Si substrate, SiO2/Si interface
and SiO2 layer. We have injected charge into the SiO2/Si sample. The localvariation and time evolution of the stored charge is clearly detected in a
nondestructive manner by the SCaM.
A New Post-Treatment for Chemical-Mechanical Polishing Process of Very Large-Scale Integrated Circuit Tungsten Vias
Authors: Park Heungsoo , Cho Yong-Jun , Song Jae-In , Koh Young-Bum , Lee Moon-Yong
Published: October 2002

A method of cleaning silicon substrates after chemical-mechanical polishing
(CMP) for the planarization of tungsten-plug patterned silicon wafers is
discussed. A phosphoric acid solution with fluoroboric acid (PFM) is used
for the post treatment process to replace the conventional scrubbing process.
The optimum chemical composition for the new solution is found to be the
mixing ratio of 1:50 (fluoroboric acid:phosphoric acid in volume) at a
phosphoric acid concentration of 40 vol%. Its oxide selectivity over
metals and particle removing power are good enough for the cleanup process
after CMP. The contact resistance of vias treated by the PFM solution
exhibits a good distribution compared to that of vias treated by conventional
scrubbing. In conclusion, the PFM solution shows promising results as a
post-treatment to W CMP of via contact formation.
Molecular Beam Epitaxial Growth and Characterization of GaAs Films on Thin Si Substrates
Authors: Maehashi Kenzo , Nakashima Hisao , Bertram Frank , Veit Peter , Christen Jürgen
Published: October 2002

In order to reduce total defect density in GaAs films grown on Si substrates, GaAs films have been grown on thin Si substrates by molecular beam epitaxy. We have fabricated two kinds of thin Si substrates. GaAs films grown on these substrates are characterized by cathodoluminescence (CL), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). CL measurements indicate that thermal stress of GaAs films on thin Si substrates is much lower than that of films on normal Si substrates. As a result, it has been clearly observed from CL, SEM and TEM images that GaAs films grown on thin Si substrates have improved surface morphology and crystalline quality.
Verification of Tersoff's Potential for Static Structural Analysis of Solids of Group-IV Elements
Authors: Koji Moriguchi Koji Moriguchi , Akira Shintani Akira Shintani
Published: October 2002

We have carried out several stringent tests of Tersoff's potential through static structural analysis of solids of group-IV elements and examined the chemical properties of the Tersoff's potential for C, Si and Ge. It is clear that Tersoff's potential has a limited ability to describe the differences in chemical reactivity between elemental Ge and Si, but well describes the chemical differences of valence s and p electron properties between elemental C and Si. Tersoff's potential has higher force constants for angular distortions than those seen in actual systems. We assume that the well-known higher melting points of Tersoff's potential are due to the larger force constants for angular distortions. The calculated elastic constants and Poisson ratios indicate congruity with the experimental values in every element. Tersoff's potential has good transferability and will be an effective tool for evaluating new materials composed of group-IV elements.
Heat Treatment of Amorphous and Polycrystalline Silicon Thin Films with High-Pressure H2O Vapor
Authors: Toshiyuki Sameshima Toshiyuki Sameshima , Mitsuru Satoh Mitsuru Satoh , Keiji Sakamoto Keiji Sakamoto , Kentaro Ozaki Kentaro Ozaki , Keiko Saitoh Keiko Saitoh
Published: October 2002

Changes in electrical and optical properties induced by heat treatment with high-pressure H2O vapor are discussed for low pressure chemical-vapor deposited amorphous silicon (LPCVD a-Si) and laser-crystallized polycrystalline silicon films. Heat treatment at 190°C with ∼1 ×106-Pa-H2O vapor reduced the dark conductivity to ∼10-11 S/cm and increased the photoconductivity to ∼10-7 S/cm. The photoconductivity was also increased for laser-crystallized polycrystalline silicon films. Optical absorption in the photon energy range lower than 1.5 eV was reduced for the a-Si films. Heat treatment at 190–270°C resulted in a minimal change in optical band gap, which was 1.50 ±0.02 eV for the LPCVD a-Si. The increase in hydrogen concentration was less than 2 ×1020 cm-3 after the treatment for the amorphous and polycrystalline silicon films. These results show that the heat treatment with high-pressure H2O vapor can reduce the defect density in the silicon films at low temperatures.
Defect Properties of CuInSe2 Single Crystals Prepared by Selenization Horizontal Bridgman Method
Authors: Hiroaki Matsushita Hiroaki Matsushita , Takeo Takizawa Takeo Takizawa
Published: October 2002

CuInSe2 bulk single crystals
have been grown using the selenization horizontal Bridgman method.
On the basis of the temperature variation of Hall coefficient curves,
we have classified the p-type CuInSe2 into
the deep (D), shallow (S) or a combination of both (B) types,
and identified that the activation energies of acceptors
are 50–60 meV for In vacancies
and 10–20 meV for Cu vacancies and Cu's in the In site.
The donors, whose densities decrease with annealing in Se atmosphere,
are ascribed to Se vacancies having an activation energy of 10 meV.
The optical band gaps of the D- and B-type samples are estimated
to be 1.04 eV at 0 K, but that of the S-type sample is 1.00 eV.
A photoluminescence peak is observed at 0.97–0.98 eV
for the D- and B-type samples,
and often other emissions at ∼1.00 and 1.04 eV,
while for the S-type sample, the peaks are observed
at 0.93 and/or 0.95–0.96 eV.
In conclusion, the activation energies of donors
are ∼30 meV for In's in the Cu site
and 5–10 meV for Se vacancies, and another level
is expected to be ∼60 meV.
Design Criterion and Operation Mechanism for 4.5 kV Injection Enhanced Gate Transistor
Authors: Kitagawa Mitsuhiko , Nakagawa Akio , Omura Ichiro , Ohashi Hiromichi
Published: October 2002

This paper investigates the injection enhancement effect of a trench gate structure for a
metal oxide semiconductor (MOS) controlled power transistor called an injection
enhanced gate transistor (IEGT). By virtue of the enhancement in effective electron
injection efficiency, 4.5 kV IEGTs attain a thyristor-like carrier profile during the on-state,
and hence achieve the same low on-state voltage drop as that of thyristors. The
operation mode of the IEGT was studied using a two-dimensional numerical simulation,
and verified by device fabrication. It was confirmed that the proposed novel trench gate
geometry acts as an injection enhancer by restricting the hole diffusion current which
flows from the n-type high-resistance base layer to the cathode electrode. It is shown
for the first time that the effective electron injection efficiency of the n-ch insulated gate
bipolar transistor increases to nearly 1. It is also shown that the new trench gate
structure effectively decreases the forward voltage drop without degradation of turn-off
capability.
Analytical Solutions of Film Planarization during Spin Coating
Authors: Chou Fu-Chu , Wu Pei-Ying , Gong Shih-Chin
Published: October 2002

Analytical solutions of film planarization for both trench and
ridge during spin coating are presented in order to offer a simple equation
to designers and researchers for describing the degree of planarization
(DOP). We found that in the case of high Ω2 (Ω2>100), DOP is
independent of d/h
f for the isolated trench and ridge. The governing
dimensionless parameter Ω2 = ρω2
w
3
r
0/(γh
f) represents the ratio of
centrifugal forces to surface tension forces in the coating where ρ and γ
are density and surface tension of the fluid, respectively, ω is rotation
speed, r
0 is radius of position of the feature on the wafer, d and w are
height and width of the feature, respectively, and h
f is liquid film
thickness.
We also found that for high Ω2 (Ω2>100), there is an identical
DOP value for trench and ridge. However, for low Ω2 (Ω2<1), the values
of DOP for trench and ridge are different even under a fixed set of Ω2 and
d/h
f. Under low Ω2 conditions, the trends of DOP variation for trench and
ridge are almost contradictory. Experimental data proposed by Peurrung
and Graves in J. Electrochem. Soc. are shown for comparison, and results
from the present analytical solutions agree with their data.
Experimental Investigation of Supersonic Free-Vortex Flow with Large Asymmetry for Aerodynamic Laser Windows
Authors: Tsunehisa Satake Tsunehisa Satake , Mitsuto Sakai Mitsuto Sakai , Takeshi Watanabe Takeshi Watanabe , Mitsuo Nakajima Mitsuo Nakajima , Kazuhiko Horioka Kazuhiko Horioka
Published: October 2002

A free-vortex supersonic nozzle with large asymmetry and minimum length was developed for aerodynamic laser windows.
The validity of the nozzle contour was confirmed by a comparison between the density distribution obtained from a
Mach-Zehnder interferogram at the nozzle exit and that from an isentropic calculation.
The pressure characteristics of the laser window strongly depended on the diffuser geometry and its configuration.
By optimization of the flowfield, the pressure ratio of the laser window was increased to 50. This value is almost 3
times larger than that of a conventional laser window.
It was found that the optical quality of the laser window was determined mostly by the shear flow instability on the
atmospheric side of the supersonic jet. Based on pressure measurements, a scaling of pressure recovery of the diffuser is
discussed so as to exhaust the jet to the atmosphere.
Large Crystals on Cu Film Surfaces Irradiated by a Glow Discharge Plasma
Authors: Katsumata Teruo , Konno Masaki , Murakami Hiroyuki
Published: October 2002

Large studded crystals grown rapidly with spiral grooves on Cu
film surfaces were observed using a scanning electron microscope
after irradiation of a glow discharge plasma. Adsorption on and
penetration into the Cu film of ions and neutral gases produced
in the glow discharge plasma were confirmed by qualitative analysis
using a scanning Auger spectrometer. The mechanism of crystal
growth was clarified by considering adsorption and penetration of
ions such as N2
+, O2
+, CO+ and O2
-, and by considering the movement
of Cu+ ions inside the Cu film, under the influence of local electric
fields between positive ions and electrons and between positive
and negative ions.
Ultrasonically Assisted and Piezoelectric Actuators Integrated Cutting Tool
Authors: Han Liang , Xu Weiliang , Tso Shiu Kit
Published: October 2002

In this paper efforts are made to refine the current cutting tool system for active error
compensation, with the aid of ultrasonic vibration cutting technique. Two piezoelectric
actuators are integrated in the cutting tool, one of which is for active error compensation and
the other for ultrasonic vibration cutting. Principles of the active compensation for cutting
error and the ultrasonic vibration cutting are first described. The characteristics of the
piezoelectric actuators are experimentally studied and finally the integrated cutting tool is
developed. Experimental cutting results have shown that the cutting tool developed is
satisfactory in terms of improved roundness and surface roughness of machined workpieces.
Anisotropy in Thermal and Electronic Properties of Single Crystal GeSe2 Obtained by the Photoacoustic Method
Authors: Nikolić P. M. , Todorović D. M. , Vujatović S. S. , Djurić S. , Mihailović P. , Blagojević V. , Radulović K. T. , Bojičić A. I. , Vasiljević-Radović D. , Elazar J. , Urosević D.
Published: October 2002

Anisotropy in the thermal and electronic properties for two directions of a
thermal wave propagation in GeSe2 single crystal was investigated using the
photoacoustic frequency transmission technique. First, the electric field of an incident
polarized light beam was adjusted to be perpendicular to the “c” axis (E
l⊥c), and
then parallel to it (E
l//c) . It is shown that there is an obvious difference in the PA
amplitude and phase spectra of the same sample, for cases when E
l//c and E
l⊥c axis.
The results for thermal diffusivity D
T obtained by fitting procedure for these two
orientations of the electric field with regard to the “c” axis, are calculated: D
T//=1.1×10-2
and D
T⊥=1.7×10-3 cm2/s, e.g. their ratio is 6.6. The electronic transport parameters are
also given: the carrier ambipolar diffusion coefficient D
//=1.5 cm2/s and D
⊥=2.5 cm2/s.
The Characteristics of Chemical Vapor Deposited Amorphous-like Tungsten Film as a Gate Electrode
Authors: Chang Kow-Ming , Deng I-Chung , Shih Chieh-Wen , Lain Kuen-Der , Fu Chao-Ming
Published: October 2002

Tungsten films are often advantageously formed by the chemical vapor deposition system which using WF6 gas through SiH4 or H2 reduction. The fluorine species will diffuse into poly-Si/SiO2/ multilayers by a driving force which is the reaction of WF6 and poly-Si gate. When too many fluorine atoms diffused into the gate oxide, the fluorine atoms will cause more strain in the gate oxide and the electrical characteristics of device will shift. An amorphous-like tungsten layer was deposited at a flow rate ratio of 2.5 of SiH4/WF6. The driving force in the amorphous-like tungsten film deposition is far less than that in selective tungsten film deposition; therefore, the concentration of fluorine atoms in the amorphous-like tungsten film is much less than in the selective tungsten film. We proved that only few fluorine atoms were incorporated in amorphous-like tungsten film which has good characteristics in the application of gate electrode.
Silicon Dioxide Thin Films Prepared from Silicon Tetraacetate Using ArF Excimer Laser by Chemical Vapor Deposition
Authors: Maruyama Atsushi , Tanaka Naoki , Nakata Kazuhiro , Yukimura Ken , Yoshikado Shinzo , Maruyama Toshiro
Published: October 2002

Silicon dioxide thin films were prepared from silicon tetraacetate
by low-pressure direct photochemical vapor deposition (photo-CVD) using
an ArF excimer laser. The film prepared by vertical irradiation of an
unheated substrate using a laser showed the lowest relative dielectric
constant which is comparable to that of the film prepared by thermal-CVD at the substrate temperature of 300°C. The relative dielectric
constant was approximately proportional to the absorbance of Si–O· and
Si–OH bond at about 950 cm-1, indicating that ionic polarization due to
the nonbridging oxygen was closely related to the relative dielectric
constant of film prepared by decomposition of silicon tetraacetate at a low
substrate temperature. Low-temperature annealing in air decreased the
amount of nonbridging oxygen and resulted in a denser film.
Measurement of Surface Impedance of Bi(Pb)–Sr–Ca–Cu–O Film under a DC Magnetic Field
Authors: Haruichi Kanaya Haruichi Kanaya , Yoshihiro Sakimoto Yoshihiro Sakimoto , Yasuo Cho Yasuo Cho , Ikuo Awai Ikuo Awai
Published: October 2002

The temperature and DC magnetic field dependence of surface impedance (Z
s) of high temperature superconducting Bi(Pb)–Sr–Ca–Cu–O (BPSCCO) films on MgO substrate were measured at microwave frequency. At a low temperature, surface resistance (R
s) increases rapidly in the low DC magnetic field range and gradually in the high-field range. However, the surface reactance (X
s) also increases rapidly in low fields but hardly changes in high fields. At high temperature, R
s shows only a monotonic increase vs the field but X
s hardly changes.
Ion Transport Analysis by Extended Wannier Theory: Effect of Ion Density Gradient
Authors: Kondo Yoshitaka , Kajita Shogo , Ushiroda Sumio
Published: October 2002

In this paper, Wannier's integral-differential equations derived from the Boltzmann equation in the cases of cold gas or high-electric-field model with a uniform ion density distribution were extended to cases having density gradients toward the field direction. Velocity distributions of ion swarm were obtained by solving these equations using numerical calculations. The mobilities and diffusion coefficients obtained from these velocity distributions agreed with ones obtained previously through Monte Carlo simulation.
Cross Sections for Electron-Impact Dissociation of Alternative Etching Gas, C3HF7O
Authors: Hideyuki Tanaka Hideyuki Tanaka , Hirotaka Toyoda Hirotaka Toyoda , Hideo Sugai Hideo Sugai
Published: October 2002

The search for alternative for perfluorocarbon gases from the environmental point of view has resulted in a new etching gas, C3HF7O (1,2,2,2-tetrafluoroethyl-trifluoromethyl ether, abbreviated as HFE-227).
In this paper, the first measurement of the absolute cross sections for the dissociation of HFE-227, is reported.
The neutral dissociation is measured from the threshold to 250 eV by appearance mass spectrometry in a dual electron beam device.
The threshold energies for the neutral dissociation into CF, CF2 and CF3 are 14.7, 12.5 and 11.2 eV, respectively.
The cross sections for the dissociation from HFE-227 into CF3 and CF are larger than those from c-C4F8 (octafluorocyclobutane), but not for the dissociation into CF2.
Besides the neutral dissociation, the cross sections for the dissociative ionization of HFE-227 are extensively measured for the formation of twelve ionic species, i.e., CO+, CHO+, CF+, CHF+, CFO+, CF2
+, CHF2
+, CF3
+, CHF3
+, C2HF2O+, C2HF4
+ and C2HF4O+.
Pulse Intense Electron Beam Irradiation on the Atmospheric Pressure N2 Containing 200 ppm of NO
Authors: Nakagawa Yoshiro , Kawauchi Hiroshi
Published: October 2002

Removal of nitrogen oxides (NO
x
) in N2 by the pulse intense electron beam irradiation
was investigated. The pulse electron beam (kinetic energy; ≤160 keV, current; ∼140 A,
current density; ∼2 A/cm2, pulse width; ∼700 ns and the electron beam energy in
one pulse; 12.6±0.4 J) was injected into a gas cell filled with 1 atmospheric pressure N2
with an initial concentration of 200 ppm of NO. The NO
x
decreased quickly and only a
small amount of NO2 was produced by the electron beam irradiation. Electron impact
dissociation of N2 and the subsequent chemical reduction of NO by nitrogen radicals
was occurred. The typical removal ratio in the gas cell of 1.7 l was about 20% for the
first shot and reached to 95% after 8 successive shots. This removal ratio corresponds
to the removal efficiency of 220–300 nmol/J. The NO
x
removal ratio and the efficiency
which depended on the length of the gas cell, the filling pressure, the initial
concentration of NO, the electron beam energy in one pulse and the axial magnetic
field were investigated.
Effect of Grain Size on Bi4Ti3O12 Thin Film Properties
Authors: Masaki Yamaguchi Masaki Yamaguchi , Takao Nagatomo Takao Nagatomo
Published: October 2002

Bismuth titanate (Bi4Ti3O12) thin films with a c-axis orientation were prepared on (100) silicon wafers by rf magnetron sputtering.
The average grain size and the c-axis lattice constant depend on the substrate temperature.
The c-axis lattice constant was decreased with increasing grain size.
The leakage current characteristics of the Bi4Ti3O12 thin film consisting of small grains with a closely packed structure, are superior to those of others.
The apparent remanent polarization and the apparent coercive field of the film with small grain sizes were estimated to be 2.4 µC·cm-2 and 2.3 kV·cm-1, respectively.
The refractive index dispersion characteristics for the film show that the large grains increase the distortion of the oxygen-octahedra.
Consequently, this result indicates that the small grain size of Bi4Ti3O12 thin films can improve the ferroelectric properties.
Preparation of Bi4Ti3O12 Thin Film on Si(100) Substrate Using Bi2SiO5 Buffer Layer and Its Electric Characterization
Authors: Kijima Takeshi , Matsunaga Hironori
Published: October 2002

Bi4Ti3O12 thin films 100, 200 and 400 nm thick were prepared on Si(100)
substrates using 30 nm Bi2SiO5 as a buffer layer, by metalorganic chemical vapor
deposition (MOCVD). It was demonstrated that c-axis-oriented Bi4Ti3O12 films can
be grown on Si substrates at 500°C using an a-axis-oriented Bi2SiO5 buffer layer.
The dielectric constant of the Bi2SiO5 film was estimated to be about 30 from
capacitance measurements. The capacitance-vs-voltage (C-V) characteristics of
Pt/Bi4Ti3O12/Bi2SiO5/Si (MFIS) structures had ferroelectric switching properties, and
the memory windows were about 0.8, 1.5 and 2.9 V for 100, 200 and 400 nm
Bi4Ti3O12, respectively. Furthermore, it was shown that the capacitance at zero bias
remains almost constant for 12 days. This suggests that Bi4Ti3O12/Bi2SiO5/Si MFIS
structures have excellent memory retention properties.
Application of Sr2Nb2O7 Family Ferroelectric Films for Ferroelectric Memory Field Effect Transistor
Authors: Yoshikazu Fujimori Yoshikazu Fujimori , Naoki Izumi Naoki Izumi , Takashi Nakamura Takashi Nakamura , Akira Kamisawa Akira Kamisawa
Published: October 2002

The compounds of the Sr2Nb2O7 (SNO) family are suitable for use
as ferroelectric materials for ferroelectric memory field effect transistors
(FETs),
because these substances have a low dielectric constant,
low coercive field
and high heat-resistance.
In this study, we succeeded in preparing
Sr2(Ta,Nb)2O7 (STN) capacitors
on polycrystalline silicon (poly-Si).
From SIMS profiles,
no interdiffusion
in the STN metal ferroelectric metal insulator semiconductor (MFMIS)
structure was confirmed.
C–V and I
D–V
G hysteresis curves
which were dependent on ferroelectric polarization were obtained.
These capacitors were applied to
floating gate type ferroelectric random access memory (FFRAM) cells.
The degradation in ferroelectricity of STN capacitors
was not observed
during FFRAM cell fabrication process.
We succeeded in operating FFRAM cells with a lower voltage
than that required for PZT
and confirmed
the drain current difference of 1 or 2 orders
at the 30 s after applying write pulses of ±5 V or ±10 V.
Ferroelectricity and Phase Transformations in Pb(Mg1/3Nb2/3)O3–PbZrO3 Solid Solution Ceramics
Authors: Yokosuka Masaru
Published: October 2002

To elucidate the ferroelectricity and phase relations of the binary system
of Pb(Mg1/3Nb2/3)O3–PbZrO3, solid solution ceramics having various
compositions were synthesized by the conventional firing process, and their
electrical and piezoelectric properties were measured as functions of
composition and temperature. X-ray studies were also conducted to
determine the crystal structure. As a result, the existence of the phase
boundary between the normal ferroelectric and the relaxor ferroelectric
states was observed, where the remanent polarization and
electromechanical coupling factors showed considerable changes. Naturally,
between these two ferroelectric states, marked differences in the dielectric
behavior such as the temperature dependence and the dispersion were
observed. In addition, lattice constants showed a slight anomaly in this
boundary region.
Inverse Modeling as a Basis for Predictive Device Simulation of Deep Submicron Metal-Oxide-Semiconductor Field Effect Transistors
Authors: Goto Hiroshi , Yamaguchi Seiichiro , Jungemann Christoph
Published: October 2002

A simple, flexible inverse modeling technique for deep submicron metal-oxide-semiconductor
field effect transistors (MOSFETs), which is based on capacitance versus voltage (C–V ) and
current versus voltage (I–V ) data measured in the so-called linear device operation regime is
presented. Based on the resultant device structure and doping profile, device simulation yields
good results not only for the linear regime but also under hot-carrier conditions. Substrate
current, for example, is well reproduced over more than five orders of magnitude. Since the
polysilicon-gate doping profile, the channel doping profile and the source/drain doping profile
are extracted separately, they can be varied independently, and it is possible to predict the
impact of process parameter variation. Good agreement between the simulation and
measurement results is found for devices with different channel implants, shallow
source/drain-extension implants or oxide thicknesses without any further inverse modeling.
Improvement of Reliability of Metal-Oxide Semiconductor Field-Effect Transistors with N2O Nitrided Gate Oxide and N2O Polysilicon Gate Reoxidation
Authors: Lai Chao Sung , Chao Tien Sheng , Lei Tan Fu , Lee Chung Len , Huang Tiao Yuan , Chang Chun Yen
Published: October 2002

A systematic study of the impact of the reliability of metal-oxide semiconductor field-effect transistors (MOSFETs) with N2O nitrided gate oxides and N2O poly-reoxidation
was conducted. The improvements include hot carrier immunity, suppression of reverse
short channel effect and suppression of plasma-induced degradation. These
improvements are due to nitrogen incorporation at the oxide/Si-substrate interface. All
data presented in this study involve substantially low thermal budget (850°C), making
this N2O-related technology extremely attractive and promising for future scaled devices.
Transverse-Mode Effect of Second-Harmonic Generation of Ultrashort Laser Pulses with Time Delay
Authors: Zhang Tiejun , Yonemura Motoki
Published: October 2002

We describe simulations of the transverse-mode effect of type II second-harmonic generation
of ultrashort laser pulses with a time delay by numerically solving a set of wave-propagation
equations. The results showed that intensity ripples appearing in the second harmonic wave
primarily result from the second-order nonlinear process and are further amplified by the third-order
nonlinear process.
Dielectric Behavior of (1-x)LaAlO3–xSrTiO3 Solid Solution System at Microwave Frequencies
Authors: Sun Pai-hsuan , Nakamura Tetsuro , Shan Yue Jin , Inaguma Yoshiyuki , Itoh Mitsuru , Kitamura Toshiki
Published: October 2002

The (1-x)LaAlO3–xSrTiO3 solid solution system with the perovskite structure was synthesized and its dielectric behavior was investigated. The lattice parameter of (1-x)LaAlO3–xSrTiO3 increases with increasing the fraction of SrTiO3 in the system. 0.45LaAlO3–0.55SrTiO3 shows a dielectric constant ε of 34, a temperature coefficient of resonant frequency τf of -8 ppmK-1 and a dielectric loss Q of 6900, which satisfy the suggested requirements for applications to mobile communications devices. The
annihilation of the ferroelectric mode of SrTiO3 corresponds to the drastic decrease of ε and τf of SrTiO3 to those of 0.25LaAlO3–0.75SrTiO3.
An Optical Sensing System Using Liquid Crystal Cells and a Corner Cube Prism Coated with Dye Films for Simultaneous Detection of an Electric Field and Decomposition Products of SF6
Authors: Marenori Kawamura Marenori Kawamura , Susumu Sato Susumu Sato
Published: October 2002

We have developed a multisensing system for simultaneously detecting an electric field and a small quantity of decomposition products generated from an electric discharge in SF6.
The sensor head consists of a twisted nematic (TN) liquid crystal (LC) cell, sandwiched between two cholesteric LC cells and a corner cube prism coated with thin dye films.
The electric field can be detected as changes in retardations induced in the TN LC cells by an electric field at a wavelength of a selective reflection band of the cholesteric LC.
Simulated and experimental results for the relationship between the sensitivity to the electric field and the thickness of the TN LC cell are discussed.
The decomposition products can also be detected as spectral changes of methyl orange dye films deposited on the surfaces of the corner cube prism at different wavelength regions outside the selective reflection band.
Physical Properties of Heavily B-doped Microcrystalline Si–Ge Alloys and Schottky Barrier of B–Si–Ge/P-Si
Authors: Osaka Yukio , Kohno Kenji , Tanabe Yukiya
Published: October 2002

The heavily B-doped microcrystalline Si–Ge alloy was prepared
for the density of B atoms of the order of 1 at.%. The hopping
conduction due to localized states near the valence band edge is
observed. The presence of localized states increases the disorder
effect due to B- atoms. The heavily B-doped µc Si–Ge has the
enhanced optical absorption at lower photon energy side than the
band-gap energy of poly SiGe. This was explained semi quantitatively
by this disorder effect. A microcrystalline B–Si–Ge/P-Si
Schottky barrier was fabricated. The dependence of
the barrier potential on Si composition agrees with the
Cowely-Sze theory, which can be applied to a metal-Si Schottky
barrier with a native oxide.
Crystal Structure and Microwave Dielectric Properties of (1-x)La(Zn1/2Ti1/2)O3–xSrTiO3 System
Authors: Cho Seo-Yong , Kim In-Tae , Hong Kug Sun
Published: October 2002

The crystal structure and microwave dielectric properties of the (1-x)La(Zn1/2Ti1/2)O3–xSrTiO3 system were investigated using X-ray powder diffraction and a network analyzer. The crystal structure of the solid solution approached that of a cubic perovskite with an increasing amount of SrTiO3. B-site cation ordering, in-phase tilting, and anti-phase tilting of oxygen octahedra disappeared at x=0.4, 0.6, and 0.9, respectively. The relative permittivity (ε
r) and temperature coefficient of resonant frequency (τf) of the solid solutions showed a nonlinear variation with no singularity. In particular, ε
r varied according to the mixture rule, 1/ε
total=v
1/ε
1+v
2/ε
2. This anomalous behavior was attributed to the structural characteristics of the system. The variation in τf of the system is discussed in conjunction with other researchers' works.