bluuebunny/crossref_metadata_2025 huggingface dataset:
Dielectric Properties of Sol-Gel Derived Pb(Mg1/3Nb2/3)O3–PbTiO3 Thin Films
Authors: Nagakari Shoken , Kousei Kamigaki Kousei Kamigaki , Shinji Nambu Shinji Nambu
Published: October 2002

Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) thin films were fabricated
using a sol-gel method. The dielectric constant was found to
be strongly dependent on the number of strong Mg–O–Nb bonds in
the precursor solution. A large number of strong Mg–O–Nb bonds
were formed after a long reflux time. This process resulted in
PMN thin films with a large dielectric constants sometimes
greater than 3000, with a loss tangent of 0.5%. Relaxor
characteristics such as weak temperature dependence and weak dc
bias dependence were also observed in the thin films. These
results suggest that PMN-PT is an important material for thin
film capacitor applications.
Crystallization of Sr0.7Bi2.3Ta2O9+α Thin Films by Chemical Liquid Deposition
Authors: Koiwa Ichiro , Kanehara Takao , Mita Juro , Iwabuchi Toshiyuki , Osaka Tetsuya , Ono Sachiko , Maeda Masakatsu
Published: October 2002

By chemical liquid deposition in which an alkoxide with a carbon number of 4
or smaller was used as raw material, a Sr0.7Bi2.3Ta2O9+α (SBTO) thin film was
fabricated for use as a ferroelectric memory device for the purpose of decreasing the
temperature of crystallization and improving surface morphology. The crystallization
process was also examined. Crystallization began when the film was heat treated in
oxygen at 650° C. When it was heat treated at higher than 700° C, it showed
ferroelectric properties, and the squareness (remanent polarization/saturation
polarization) of its hysteresis loop was improved at 800° C. A film heat treated at
temperature 650° C was a cluster of fine particles, and a film heat treated at 800° C
was a cluster of large particles. A film heat treated at 700° C was a mixture of fine
particles and large particles. Therefore, it is concluded that the alkoxide with a
carbon number of 4 or smaller as raw material enable the lowering of the heat-treatment temperature and improvement of the surface morphology of SBTO thin films.
Playback Techniques for a Video-on-Demand System Using an Optical Mass Storage System
Authors: Mori Tatsuo , Suzuki Hideharu , Kazutoshi Nishimura Kazutoshi Nishimura , Hirotaka Nakano Hirotaka Nakano
Published: October 2002

One serious problem for digital video-on-demand system based on high-speed digital networks and video compression is achieving multiple quick access for mass storage. We have already proposed hierarchical storage techniques using magnetic disks and an optical mass storage system (MSS) that has been applied to video-on-demand (VOD) system. In this paper, we propose new playback techniques for the optical MSS. To solve the problems that occur when optical MSS are used in video-on-demand services, we have proposed techniques such as playback linking, visual search and multiple readout in a storage hierarchy with magnetic disks. Another technical problem is how to implement jump functions with multiple access in optical MSS. We propose a multiple magneto-optical (MO) disk drive arrangement and VOD restrictions for executing multiple readout.
Preparation of (Pb, La)(Zr, Ti)O3 Ferroelectric Films by RF Sputtering on Large Substrate
Authors: Suu Koukou , Osawa Akira , Tani Noriaki , Ishikawa Michio , Nakamura Kyuzo , Ozawa Takanori , Sameshima Katsumi , Kamisawa Akira , Takasu Hideshi
Published: October 2002

(Pb, La)(Zr, Ti)O3 (PLZT) thin films were deposited on 6-inch Pt/Ti/SiO2/Si substrates by rf magnetron sputtering using a multichamber production system. The Pb content in PLZT films deposited at low temperature was measured by inductively coupled plasma (ICP) spectroscopy, and the structural properties of crystallized PLZT films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A novel method for Pb content control was developed and it was found that Pb content in PLZT film could be changed by changing the electric potential of the substrate. For ferroelectric properties, only small differences were observed between the rapid thermally annealed PLZT film and furnace- annealed ones. Good uniformities of film thickness, Pb content and remanent polarization were achieved on 6-inch wafers.
Dielectric Properties of (Pb, La)TiO3 Thin Films by Multiple-Cathode Sputtering and Its Application to Dynamic Random Access Memory Capacitors
Authors: Ichinose Hiroshi Maiwa
Published: October 2002

(Pb, La)TiO3 (PLT) thin films were fabricated by multiple-cathode RF-magnetron sputtering. PLT
films deposited on Pt/SiO2/Si at 460° C had a perovskite structure with preferred orientation in the
(111) plane. The diffuse phase transition behavior was observed for the deposited PLT thin films.
Thickness dependence and La content dependence of the electrical properties of the deposited PLT
thin films are discussed. The dielectric constant and leakage current of the 100-nm-thick
PLT(La/Ti=0.28) thin films were 396 and 10-7 A/cm2 (at a field of 500 kV/cm). These results indicate
that the PLT thin films fabricated by multiple cathode RF magnetron sputtering are suitable for
dynamic random access memory (DRAM) applications.
PbTiO3 Films Grown by the Liquid Phase Epitaxy Method
Authors: Morikoshi Hiroki , Uchida Nobuya , Nakata Akio , Kazuhito Yamasawa Kazuhito Yamasawa , Yoshikazu Narumiya Yoshikazu Narumiya
Published: October 2002

PbTiO3 films were grown on SrTiO3 substrates using the liquid phase epitaxy (LPE) method. Single-crystal films with (001) orientation were successfully grown at 410° C, which is lower than the Curie temperature (T
c). The full width at half-maximum (FWHM) of the X-ray rocking curve for the (001) plane was determined to be 0.62 degrees. This result indicates that the grown film has good crystallinity. The lattice spacing of the (001) plane ( c-axis) was 4.121 Å, which is smaller than that of bulk crystal. Thus, it is considered that tensile stress is applied parallel to the film/substrate interface. The interface was examined using a transmission electron microscope (TEM). It is found that there are 90° domains, which extend from the interface to the film surface. The film/substrate interface is well defined, although some dislocations can be seen. Electron diffraction patterns showed that the films were formed epitaxially.
Fabrication of Thin Film Phase Grating Using Surface Acoustic Waves
Authors: Masahiko Watanabe Masahiko Watanabe , Yasuhiko Nakagawa Yasuhiko Nakagawa , Shouji Kakio Shouji Kakio
Published: October 2002

It was found for the first time that a phase grating was formed with variations in thickness and refractive index with a period of half the wavelength of surface acoustic waves, when a thin film was deposited on a substrate in which a standing surface wave was excited.
No such phenomenon has been reported before, and its application to optical elements is expected to be a new application of surface acoustic waves.
Oxidation and Heat Treatment Effect on Crystal Structure and Electrical Conductivity of Ferroelectric Pb(Zr, Ti)O3 Films
Authors: Yoichiro Masuda Yoichiro Masuda , Akira Baba Akira Baba
Published: October 2002

Ferroelectric PZT thin films were grown by metalorganic chemical vapor
deposition (MOCVD). The crystal structure and chemical composition ratio of
synthesized PZT films were analyzed by X-ray diffraction and fluorescence X-ray
analysis. The lattice parameters of a typical PZT film were a=4.017 Å and
c=4.177 Å, with tetragonality c/a=1.04. The chemical formula of an as-deposited
film was estimated to be Pb0.98(Zr0.39, Ti0.61)O2.98 from fluorescence X-ray analysis.
Deposited films were annealed under 2 kg/cm2 O2 gas atmosphere
for 1 h at 700° C in an electric furnace, and the electrical conductivity of annealed
films was decreased. The dielectric constant was measured to be 480.
Static Characteristics of Piezoelectric Thin Film Buckling Actuator
Authors: Wakabayashi Shuichi , Sakata Minoru , Goto Hiroshi , Masashi Takeuchi Masashi Takeuchi , Tsuneji Yada Tsuneji Yada
Published: October 2002

We have developed a diaphragm piezoelectric microactuator. The diaphragm consists of a
Pb(Zr, Ti)O3 (PZT) thin film, electrode layers, an isolation layer and a Si substrate. The diaphragm
is deflected by transverse stress in the PZT thin film which is fabricated by a sputtering and
annealing process. The PZT thin film has a piezoelectric coefficient d
31 of -100 pC/N, which is
comparable to that of bulk PZT. A diaphragm deflection of 3 µ m was obtained at an electric field
of 16 V/µm.
High Power Transformer Employing Piezoelectric Ceramics
Authors: Kawai Hidemasa , Sasaki Yasuhiro , Inoue Takeshi , Inoi Takayuki , Takahashi Sadayuki
Published: October 2002

0.10Pb(Mn1/3Sb2/3)O3–0.47PbZrO3–0.43PbTiO3 piezoelectric ceramics in a single-layer transformer
successfully produces a maximum available power of 11 W. This 42×10×1 mm piezoelectric
transformer operates in a third order length expansion vibration mode, with a load impedance of
100 k Ω at the output terminal. Two types of ceramic fabrication have been tested: one using 5.5 m2/g
specific surface area calcined powder sintered at 1100° C, the other using 2.0 m2/g specific surface
area calcined powder sintered at 1300° C.
While such ceramics are expected to be especially useful in multilayered structure transformers,
as well, sintering at 1100° C would be preferred for multilayer designs because relatively low cost
metals, such as Ag–Pd alloys, could be employed for the internal electrodes. With ceramics sintered
at 1300° C, however, high cost metals such as Pt would have to be used.
Thin Vibrator Alarm Using a Cantilever Piezoelectric Actuator
Authors: Kusakabe Chiharu , Tomikawa Yoshiro , Takano Takehiro , Tamura Hideki , Hideaki Okamoto Hideaki Okamoto
Published: October 2002

This paper deals with a cantilever piezoelectric vibrator
alarm, which is aimed to be used in such telecommunication
devices as pagers and portable telephones. A specific merit
of this new alarm is that it is soundless and is available in a
very thin form because of its simple construction. As results
of experimental investigations, the tactile sense and the
vibrational amplitude achieved by a pager equipped with the
vibrator alarm were found to be similar to those of pagers
currently on the market, in which a DC motor alarm was utilized.
Phase Change Optical Disk Using Land and Groove Method Applicable to Proposed Super Density Rewritable Disc Specifications
Authors: Miyagawa Naoyasu , Ohno Eiji , Kenichi Nishiuchi Kenichi Nishiuchi , Nobuo Akahira Nobuo Akahira
Published: October 2002

We have developed high-recording-density phase change optical disks applicable to the proposed Super Density Rewritable Disc (SD-RAM) specifications using the land and groove method. From experiments we confirmed that GeSbTe phase change optical disks employing this recording method have the following tolerances; ±12/±9 mrad for radial tilt during reading/writing; ±11/±8 mrad for tangential tilt during reading/writing; more than ±0.07 µm for offtrack free from cross track erase.
Ring-Form Two-Dimensional (X–Y) Moving Piezoelectric Actuator
Authors: Takehiro Takano Hidetoshi Hata
Published: October 2002

This paper deals with a ring-form two-dimensional (X–Y) moving piezoelectric actuator.
Use of this actuator enables, for example, a short distance stroke of a few mm for a lens in a camera.
The actuator has two moving functions of rotational and linear motions.
A combination of these two functions drives the actuator effectively; that is, such functions wherein first, the moving direction angle is determined by the rotational motion and next, the linear motion gives the straight moving distance, can be made possible.
The actuator is constructed using a ring-form piezoelectric multimode vibrator in which three resonance modes degenerate: two of them are B21 and B21' bending modes of the same form which have two nodal circles and a nodal diameter, and the other is the first radial vibration mode (R,1).
In this paper, the operation principle of the actuator and its basic characteristics of linear and rotational motions are shown, and moreover, the driving force characteristics are also presented and quantified.
Vertical-Cavity Surface-Emitting Lasers for Optical Data Storage
Authors: Shin Hyun-Kuk , Kim Il , Kim Eui-Joong , Kim Jin-Hwan , Lee Eun-Kyung , Lee Moon-Kyu , Mun Jong-Kuk , Choon-Seong Park Choon-Seong Park , You-Shin Yi You-Shin Yi
Published: October 2002

The application of vertical-cavity surface-emitting laser (VCSEL) diodes for optical data storage has been investigated. VCSELs suitable for compact disc optical heads have been designed and fabricated. A photo diode for optical power monitoring is integrated in a VCSEL chip, and a holographic optical head using VCSEL is also manufactured. Single transverse mode operation up to 1.5 mW shows good performance.
Effect of Firing Atmosphere on Densification of Semiconducting (Ba, Sr)TiO3 Ceramics and Their Dielectric Properties and Varistor Characteristics
Authors: Tashiro Shinjiro , Tomohiro Ishiya Tomohiro Ishiya , Hideji Igarashi Hideji Igarashi
Published: October 2002

A new atmospheric-gas firing process is demonstrated to be effective for the densification of semiconducting (Ba, Sr)TiO3 ceramics having a positive temperature coefficient of resistivity (PTCR). In the new atmospheric-gas firing process, oxygen atmosphere is introduced in the heating stage of the former reduction-reoxidation firing. Thereby the
density of ceramics was increased to 97% from 91%. The optimum Mn concentration for a capacitive varistor increased to 0.20 atm% from 0.11 atm% compared to previous samples with porous ceramic bodies.
Electrical Properties of Low-Temperature (450°C) Pb(Zr,Ti)O 3 Films Prepared in Quasi-Metallic Mode by RF Reactive Sputtering
Authors: WeiXiao Zhang WeiXiao Zhang , Kimihiro Sasaki Kimihiro Sasaki , Tomonobu Hata Tomonobu Hata
Published: October 2002

Ferroelectric lead zirconate titanate (PZT) thin films were prepared on Pt/Ti/SiO2/Si substrates from a ZrTi (50%/50%) alloy target combined with PbO pellets using an rf reactive sputter deposition technique. Perovskite PZT films were obtained at a growth temperature as low as 450°C in the quasi-metallic mode. Crystalline structure, depth profiles, ferroelectric and dielectric characteristics of the films prepared from the (ZrTi+30%PbO) target were investigated. The interdiffusion between the PZT film and the Pt/Ti/SiO2/Si substrate was suppressed by the low-temperature sputtering. The remanent polarization, leakage current and dielectric constant decrease with increasing growth temperature. The perovskite films prepared at 450°C exhibit the remanent polarization of 20 µC/cm2, the coercive field of 150 kV/cm, the leakage current smaller than 10-6 A/cm2 at the electric field lower than 235 kV/cm, and the dielectric constant as high as 561.
Low Temperature Deposition of (Ba, Sr)TiO3 Films by Electron Cyclotron Resonance Plasma Chemical Vapor Deposition
Authors: Sone Shuji , Yabuta Hisato , Kato Yoshitake , Iizuka Toshihiro , Yamamichi Shintaro , Yamaguchi Hiromu , Lesaicherre Pierre-Yves , Nishimoto Shozo , Masaji Yoshida Masaji Yoshida
Published: October 2002

(Ba, Sr)TiO3 films deposited by electron cyclotron resonance plasma chemical
vapor deposition at 450° C and 500° C are investigated. The crystallinity, evaluated
by X-ray diffraction and by measuring grain size, and electrical properties of films were
evaluated for changes in deposition temperature, deposition rate, and Ba content,
without a post-deposition annealing. Slower deposition rates as well as higher
deposition temperatures were found to improve film crystallinity. Evaluation of
electrical properties and film crystallinity revealed that the optimum Ba content of a
film deposited at 500° C was 0.4. A 27 nm thick film deposited on a Pt substrate at
500° C and at 1.1 nm/min with a Ba content of 0.4 exhibited a SiO2 equivalent
thickness of 0.65 nm and a leakage current density of 4.6×10-7 A/cm2 at 1 V. The
film composition was found to be sufficiently uniform throughout, i.e., from the top to
the side of the films on a stacked bottom electrode.
Preparation and Properties of Pb(Sc1/2Nb1/2)O3–Pb0.85La0.15Ti0.96O3 (PSN-PLT) Solid-Solution Ceramics
Authors: Adachi Masatoshi , Toshima Takeshi , Jin Yachizaka Jin Yachizaka , Akira Kawabata Akira Kawabata
Published: October 2002

Pb(Sc1/2Nb1/2)O3–Pb0.85La0.15Ti0.96O3 (PSN-PLT)
solid-solution ceramics were prepared by the hot isostatic pressing (HIP) method in order to improve their porosity. Before
sintering by the HIP, the two step calcining and ordinary sintering at around 1275° C for PSN and 1290° C for
PSN-PLT were carried out. The highest density of 7.90 g/cm3 for PSN-PLT ceramics with 40 mol% PLT was obtained,
which is in the range of 99.5% of the theoretical value. The maximum electromechanical coupling factors k
p of 0.68
and k
t of 0.55 were obtained in this PSN-PLT system close to the MPB composition.
The dielectric constant of HIP PSN-PLT ceramics with the 40 mol% PLT was 5300 at room temperature, which is higher than that
of the Pb(Sc1/2Nb1/2)O3–PbTiO3 (PSN-PT) system. Physical and electrical properties of one of the end
members PSN and PLT, relaxor ferroelectric PSN, are also investigated.
Improvement of Spatial Frequency Response Characteristics in Optical Scanning System with Coaxial Dual Beams
Authors: Makoto Kato Makoto Kato , Ken'ichi Kasazumi Ken'ichi Kasazumi
Published: October 2002

A new method to improve resolution characteristics in an optical scanning system with orthogonally polarized dual beams and differential detection is proposed. Improvement of the spatial response by a factor of 1.4 was confirmed experimentally and numerically.
Sintering of (Pb, La)(Zr, Ti)O3 in Ozone Atmosphere and Its Ferroelectric Properties
Authors: Yoshihiro Kawazu Yoshihiro Kawazu , Kaoru Tsuzuki Kaoru Tsuzuki
Published: October 2002

Sintering behaviors of (Pb, La)(Zr, Ti)O3 (PLZT 8/65/35) ceramics
in ozone atmosphere and their ferroelectric properties were investigated.
In the early stage of sintering, the presence of ozone prompted the growth
of crystallites and grains, and promoted densification. Ozone content
dependence of these structural factors of ceramics influenced their optical
transmittances, and ferroelectric and electrooptic properties. Marked
improvement of electrooptic coefficients (R=30×10-16 m2/ V2, V
π=10 V
with 0.40-mm-thick plate) was obtained for ceramics sintered at 1100° C
for 24 h in an ozone-rich (180 ppm) atmosphere, as compared with ozone-free ceramics.
Fine Grained Relaxor Dielectric Ceramics Prepared by Hydrothermally Synthesized Powder
Authors: Kanai Hideyuki , Harada Koichi , Yamashita Yohachi , Hasegawa Koichi , Mukaeda Satoshi , Handa Kiyoji
Published: October 2002

In response to the demand for small grain size in thin dielectric layers
of multilayer capacitors (MLCs), relaxor dielectric powder was hydrothermally
synthesized. The sintering temperature for the hydrothermally synthesized
powder was reduced to 950° C from 1200° C for the conventional
solid phase reaction synthesized powder. As a result, the grain size of sintered specimens decreased
from 3.9 µm for the solid phase reaction synthesized powder as a starting powder to
1.3 µm for hydrothermally synthesized powder: this is equivalent to the
smallest grain size of a commercially available X7R-designated barium titanate-based
dielectric fired at 1300° C.
Using the hydrothermally synthesized powder, Y7R-designated 7.4 µF MLCs
with 3.2 µm-thick 240 dielectric layers of EIA1206 size (3.2×1.6×1.5 mm)
were fabricated. The MLCs were fired at 1000° C for 2 h and the grain
size was 1.3 µm. The capacitance per unit volume of these MLCs is
approximately 900 µF/cm3, which is comparable with that for tantalum capacitors.
In addition, the new MLCs have a low dissipation factor of 1.3%
and stable dependence of capacitance on dc bias voltage as compared with
BaTiO3-based MLCs.
Crystal and Electrical Characterizations of Epitaxial CeXZr1-XO2 Buffer Layer for the Metal/Ferroelectric/Insulator/Semiconductor Field Effect Transistor
Authors: Hirai Tadahiko , Nagashima Kazuhito , Koike Hiroshi , Matsuno Shinya , Yasuo Tarui Yasuo Tarui
Published: October 2002

We evaluated the crystallinities of Ce

X

Zr1-
X

O2 (X=0.10–0.20) thin films used as intermediate layer for metal/ferroelectric/insulator/semiconductor field effect transistors (MFIS-FETs), using reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and X-ray pole figure measurement. The crystal alignments of Ce

X

Zr1-
X

O2 films on Si(100) were Ce

X

Zr1-
X

O2[100]//Si[100] or Ce

X

Zr1-
X

O2[100]//Si[001], in the plane. The breakdown field of Ce

X

Zr1-
X

O2 was about 3 MV/cm (at I=1 nA/cm2). From C-V measurements, it was found that the electrical properties of the intermediate layers of the MFIS-FETs were good.
Oriented perovskite PbTiO3 films were deposited on Ce

X

Zr1-
X

O2/Si(100) substrates by digital chemical vapor deposition (CVD). These PbTiO3 films included many PbTiO3 grains aligned with the [100] or [001] axis parallel to the [101] axis of the Ce

X

Zr1-
X

O2 crystals at the plane in the PbTiO3/Ce

X

Zr1-
X

O2 interface. From C-V measurements of an Al/PbTiO3/Ce

X

Zr1-
X

O2/Si(100) sample, we obtained a threshold hysteresis (memory window) of about 1.4 V.
New Photorefractive Ferroelectric Material for Red and NearInfraRed: Tin Hypothiodiphosphate
Authors: Odoulov Serguey , Shumelyuk Alexandr , Hellwig Ute , Rupp Romano , Brost George
Published: October 2002

New photorefractive crystal is described which can be easily sensitized to
near infrared radiation by pre-illumination to incoherent white light with
moderate intensity. The gain factor up to 7 cm-1 and the response time
down to 10 ms are measured for unexpanded beams of CW radiation of a
1.06 µm Nd3+:YAG laser with 0.5 W output power.
Dielectric Activity and Ferroelectricity in Piezoelectric Semiconductor Li-Doped ZnO
Authors: Akira Onodera Akira Onodera , Norihiko Tamaki Norihiko Tamaki , Yuko Kawamura Yuko Kawamura , Takuya Sawada Takuya Sawada , Haruyasu Yamashita Haruyasu Yamashita
Published: October 2002

Temperature dependences of dielectric constants, specific heat andD–Ehysteresis loops of Li-doped zinc oxide ceramics were investigated. A new dielectric anomaly was found at 330 K in Zn1-xLixO withx=0.17. A cusp-like anomaly was also found in specific heat. A ferroelectricD–Ehysteresis loop was successfully observed for the first time. These observations suggest that replacement of host Zn ions by small Li ions induces a ferroelectric phase in the wurtzite-type ZnO piezoelectric semiconductor. This material is a candidate for ferroelectric thin films in integrated ferroelectric devices.
Anomaly in the Infrared Active Phonon Modes and Its Relationship to the Dielectric Constant of (Ba1-xSrx)(Mg 1/3Ta 2/3)O 3 Compound
Authors: Toru Nagai Toru Nagai , Masaaki Sugiyama Masaaki Sugiyama , Mutsuo Sando Mutsuo Sando , Koichi Niihara Koichi Niihara
Published: October 2002

A characteristic change in the dielectric properties with A-site
substitution is known in complex perovskite compounds, (Ba, Sr)(B',
B")O3, which are expected to be applied to dielectric resonators.
Recently, a phase transformation upon tilting of oxygen octahedra has been
found in some of the compounds. However the oxygen tilting transformation
has not been considered to affect the dielectric constant explicitly. To
clarify the relationship between the dielectric constant and the phase
transformation, dielectric properties of a solid-solution system,
(Ba1-x
Sr
x
)(Mg1/3Ta2/3)O3, have been studied. The
origin of the dielectric constant, the polar mode of the lattice vibration,
has been investigated using infrared reflectivity spectroscopy and the
Kramers-Kronig analysis. It was found that the phase transformation due to
the tilting of the oxygen octahedra clearly affects polar phonon modes of
the compound. The origin of the change in the dielectric properties with Sr
concentration is discussed referring to the behavior of polar phonon
modes.
Time Evolution of Surface Topography around a Domain Wall in Ferroelectric (NH2CH2COOH)3·H2SO4
Authors: Ohgami Junji , Sugawara Yasuhiro , Morita Seizo , Nakamura Eiji , Ozaki Tōru
Published: October 2002

Time evolution of surface topography around a domain wall was
investigated on a cleaved (010) surface of ferroelectric
(NH2CH2COOH)3·H2SO4 (TGS) using an atomic force microscope
(AFM). We found the following time evolution of the surface
topography during 32 hours in air at room temperature. First the
migration of the domain wall induced the migration of a small step
on the domain wall. The height of the small step decreased from 2–3 Å to 0–1 Å. Holes having a narrow and long tail extending to
the domain wall were transformed. Parts of cleavage steps crossing the domain wall were also transformed. Round holes and islands
with diameters smaller than ∼100 nm shrank in size.
Field-Excited Electron Emission from ( 1-y)Pb(Mg 1/3Nb 2/3)O 3-yPbTiO 3 Ceramic
Authors: Yasuhiro Kuratani Yasuhiro Kuratani , Masanori Okuyama Masanori Okuyama , Yoshihiro Hamakawa Yoshihiro Hamakawa
Published: October 2002

Electron emission from a (1-y)Pb(Mg1/3Nb2/3)O3-yPbTiO3 (PMN-PT) ferroelectric ceramic plate has been observed in vacuum by applying a pair of bipolar pulse voltages. The emission is observed even at temperatures above the Curie temperature, as is that of a lead-zirconate-titanate (PZT) ceramic plate. The amount of emitted charge from PMN-PT ceramic is about 5 times larger than that from PZT ceramic, and increases with increasing pulse width. Furthermore, the temperature dependence of the emitted charge suggests that the amount of emitted charge depends strongly on the dielectric constant of the sample. It is considered that the emission is induced by abrupt change of dielectric flux as well as the polarization reversal.
Raman Scattering Study of Cubic to Tetragonal Phase Transitions in Mixed System AxBa1-xTiO3
Authors: Kojima Seiji , Ikeuchi Yasuo , Zhunchang Huang , Qingrui Yin
Published: October 2002

The ferroelectric phase transition with the point group change from
m3m to 4 mm in the mixed system A

x

Ba1-
x

TiO3 (A=Pb, Sr) was studied by
Raman scattering measurements. The low frequency spectra show
strong dependence on both composition and temperature. The square of
the soft mode frequency shows a linear dependence on T
c. While, in
temperature dependence, the soft mode of Pb0.14Ba0.86TiO3 slightly
decreases towards T
c on heating, but the softening is suppressed near
T
c. Peak frequencies higher than 100 cm-1 are insensitive to both
composition and temperature. The mode intensity gradually decreases
with increasing temperature. In spite of the fact that all optical
modes should be Raman inactive above T
c, a few modes are still
observed in the spectra.
Ferroelectric Behavior in Thin Films of Polyurea-5
Authors: Tajitsu Yoshiro , Ohigashi Hiroji , Hirooka Ayumu , Yamagishi Akira , Date Munehiro , Hattori Takeshi , Fukada Eiichi
Published: October 2002

Thin polyurea-5 films were prepared by vapor-deposition
polymerization of 1,5-diaminopentane and 1,5- diisocyanatepentane.
In order to investigate the ferroelectric properties of polyurea-5, we used dielectric hysteresis measurements. Ferroelectric
hysteresis loops were observed for the polymer thin film at room
temperature. The dielectric hysteresis curve shows large
polarization values above 70° C, which are much larger than the
calculated value of the spontaneous polarization in the single crystal of polyurea-5. To evaluate the residual polarization, sinusoidal
electric fields with varying frequency were applied at various
temperatures and the time variation of the electric displacement was
detected by a charge amplifier. As a result, we obtained a residual
polarization of about 25 mC/m2 at temperatures in the range of 20–70° C.
This value is consistent with a polyurea-5 film crystallinity of 50%.
Effect of Fe Impurities on the Generation of Process-Induced Microdefects in Czochralski Silicon Crystals
Authors: Jablonski Jaroslaw , Saito Mina , Yoshiji Miyamura Yoshiji Miyamura , Masato Imai Masato Imai
Published: October 2002

The enhancement effect of Fe impurities on the generation of surface and bulk microdefects, such as oxidation-induced stacking faults, oxide precipitates, precipitate-dislocation complexes and bulk stacking faults, has been observed in annealed silicon wafers prepared from Czochralski grown crystals intentionally contaminated with iron. The effect remains significant even for an Fe concentration as low as 1012 atoms/cm3. It has been found that Fe facilitates the nucleation of oxide precipitates in silicon. The mechanism of Fe-assisted nucleation of oxide precipitates is discussed. The effect of Fe on the generation of oxidation-induced stacking faults is explained, assuming that both oxide precipitates and Fe:Si precipitates formed near the wafer surface serve as active nucleation sites of these microdefects.
Grain Size Dependence of Switching Properties of Ferroelectric BaTiO3 Ceramics
Authors: Mitoseriu Liliana , Ricinschi Dan , Harnagea Catalin , Okuyama Masanori , Tsukamoto Takeyo , Vasile Tura Vasile Tura
Published: October 2002

Polarization reversal properties of BaTiO3 (BT) ferroelectric ceramics at room temperature
were studied. Two types of samples, having g
1=1.5 µ m and g
2=70 µ m grain size, were used.
The grain size effect on the transient switching current was analysed and compared with the results of
two theoretical models accounting for size effects: a dipole lattice model and a finite grain size model
(FGM) that uses a Kolmogorov-Avrami (K-A) type statistical approach of polarization reversal.
Crystallization of Precursor Micropatterns of Ferroelectric Bi 4Ti 3O 12 Fabricated by Electron Beam Scanning
Authors: Soichiro Okamura Soichiro Okamura , Yukie Yagi Yukie Yagi , Atsushi Kakimi Atsushi Kakimi , Shizutoshi Ando Shizutoshi Ando , Katsumi Mori Katsumi Mori , Takeyo Tsukamoto Takeyo Tsukamoto
Published: October 2002

Crystallization of precursor micropatterns of ferroelectric Bi4Ti3O12 fabricated by electron beam scanning was investigated in comparison with that of thin films. Precursor solutions were prepared by mixing bismuth and titanium octylates with various
Bi : Ti molar ratios. Single-phase Bi4Ti3O12 thin films were formed by spin-coating a solution containing Bi and Ti atoms at a molar ratio of 5.2 : 3.0 and successive heat treatment. It was possible to control orientation of the Bi4Ti3O12 thin films by changing the sintering temperature. Bi4Ti3O12 thin films consisting of platelike crystals with predominantly c-axis orientation were obtained by sintering at 800°C. Precursor micropatterns were fabricated by scanning an electron beam on metal octylate films and development with toluene. They were crystallized into single-phase Bi4Ti3O12 by sintering at 800°C. However, the Bi4Ti3O12 micropatterns consisted of small grains, unlike the large platelike crystals in thin films. There was a clear difference in crystallization between the thin films and the micropatterns.
Poling Field Dependence of Ferroelectric Domains in Tetragonal Lead Zirconate Titanate Ceramics
Authors: Yamada Ayako , Chung Yul-Kyo , Masahiro Takahashi Masahiro Takahashi , Toshio Ogawa Toshio Ogawa
Published: October 2002

The ferroelectric domain structures of tetragonal lead zirconate
titanate (PZT) ceramics were evaluated by investigating the poling field (E)
dependence of the planar coupling factor (k
p) and the relative intensity of
X-ray diffraction (002) peak, I
002. Fifteen typical domain configurations were
proposed. Furthermore, we selected the two patterns which make a domain
configuration model with 90° and 180° domains. It was thought that the
change in domain structure due to poling could be explained by calculating
the change in area of domain for each axis. Therefore, the total number of
domains oriented along the c axis was estimated from using the relationship
between I
002, k
p, the normalized polarization and E. Using our domain
configuration model, it was confirmed that there were two peaks
corresponding to 90° domain rotation and one peak corresponding to 180°
domain switching. After the 90° domain rotation occurred, the domains along
the c axis were changed mainly by 180° switching. As a result, the degree of
90° domain rotation decreased and that of 180° domain switching increased.
Our study on domain structures in bulk ceramics is useful for understanding
the degradation characteristics of PZT thin films.
An Electron Nuclear Double Resonance and Electron Spin Resonance Study of Isotropic CO2
- and SO2
- Radicals in Natural Carbonates
Authors: Idrissi Samira , Callens Freddy , Moens Peter , René Debuyst René Debuyst , Fernand Dejehet Fernand Dejehet
Published: October 2002

Natural samples often exhibit isotropic electron spin resonance (ESR) signals at g=2.0006 ( CO2
-) and g=2.0057 ( SO2
-). Electron nuclear double resonance (ENDOR) data were collected for various calcitic or aragonitic samples of marine origin. The small and isotropic 1H hyperfine ENDOR splitting (250–350 kHz) is explained by a locally disordered water environment for these species. As for the isotropic CO2
- and CO3
- radicals in synthetic monohydrocalcite and apatite, the radicals are most probably located in the occluded water embedded in these samples, and not in the crystal matrix.
Operation and Performance of a Two-Stage Blumlein Transversely Excited Atmospheric Nitrogen Laser
Authors: Tou Teckyong , Kuanhiang Kwek Kuanhiang Kwek , Duusheng Ong Duusheng Ong
Published: October 2002

In this paper we present a new electrical arrangement, a two-stage Blumlein circuit, for the excitation of a nanosecond transversely excited atmospheric nitrogen ( TEA-N2) laser. The circuit consists of three discharge loops controlled by two spark gaps. By means of temporal adjustment in the second two-electrode spark gap, the laser channel was made to break down at the highest possible overvoltage. This produced a high laser output with low shot-to-shot fluctuation which was correlated to the enhanced discharge characteristics in the laser channel namely, high current and low plasma resistance.
Second Harmonic Generation from Surface Crystallized Li2O–Ta2O5–SiO2 Glass
Authors: Hase Hiromi , Nasu Hiroyuki , Mito Akihiro , Hashimoto Tadanori , Matsuoka Jun , Kanichi Kamiya Kanichi Kamiya
Published: October 2002

Preferential c-axis orientation of LiTaO3 was observed in surface crystallized 35Li2O·30Ta2O5·35SiO2 glass. Second harmonic generation (SHG) was observed in surface crystallized glass poled at room temperature for 24 h under a 0.7 kV dc voltage, whereas it was not observed in an unpoled sample. The SHG observed in this study was attributed to residual polarization in LiTaO3. The d
33 value of the poled sample was estimated as 0.13 pm/V which was 0.5% of the d
33 value for LiTaO3 single crystal.
Evidence for Mixed State in Terbium
Authors: M. Akhavan M. Akhavan
Published: October 2002

Evidence for the existance of a previously unresolved additional mixed state in terbium single crystals is obtained in the temperature range 190 to 220 K. Magnetoresistance measurements are reported in an applied magnetic field, continuously changing to a maximum of 23 kOe, and in the temperature range 80 to 300 K. Longitudinal and transverse measurements were made with the current and the field in the [0001], [10\overline10], and [2\overline1\overline10] directions. Anomalies in the magnetoresistance are correlated here with field-induced magnetic phase modifications. Certain details of the measurement techniques employed have been found to be of importance: It is essential that the samples' internal magnetic fields have high homogeneity and that the specimen is mounted in such a way as to provide for the relief of thermal and magnetostrictive stresses.
Theoretical Study of Momentum Matrix Elements of GaN
Authors: Masakatsu Suzuki Masakatsu Suzuki , Takeshi Uenoyama Takeshi Uenoyama
Published: October 2002

The interaction between the conduction band and valence bands in wurtzite GaN is theoretically investigated by means of the first-principles calculation and thek\cdotpptheory. The momentum matrix elements are derived from the first-principles electronic band structure, calculated by a full-potential linearized augmented plane wave method. We also show analytical expressions of the momentum matrix elements, based on the 8×8k\cdotpptheory for the wurtzite structure. The values estimated from the analytical expressions are in good agreement with those obtained from the first-principles calculation.
Specific Heat of ErNi in Magnetic Fields and Its Performance as Regenerator Material in Gifford-McMahon Refrigerator at Cryogenic Temperatures
Authors: Yayama Hideki , Hatta Yoshiro , Tomokiyo Akihisa , Okamura Masami , Tokai Yoichi , Takahashi Akiko , Hashimoto Takasu
Published: October 2002

Specific heat of the rare earth compound ErNi is measured in magnetic fields up to 5 T in the temperature range 4.2 to 35 K. The specific heat under applied magnetic field of 1 T is larger than that of Er3Ni below 16 K. The numerical simulation of a Gifford-McMahon cycle shows that the refrigeration capacity using an ErNi regenerator is larger than that using one of Er3Ni or lead. It is shown for the first time that the refrigeration capacity can be increased by application of a weak magnetic field to the ErNi regenerator.
Aberrations as a Function of Reduction Factor in Symmetric Magnetic Doublet for Electron Beam Image Projection System
Authors: Mamoru Nakasuji Mamoru Nakasuji
Published: October 2002

When the object-image distance is 546 mm and the main- and sub-field sizes are 20 and 0.25 mm, the distortions for the reduction factors of 1/4, 1/2.5, 1/2, 1/1.6 and 1/1 are 2.1, 1.8, 1.3, 0.6, and 0.2 nm, respectively. The maximum obtainable beam currents for the reduction factors of 1/2.5, 1/2, 1/1.6, and 1/1 respectively are 1.6 1.7, 2.0, and 2.0 times as large as that for the reduction factor of 1/4. A new lithography system is studied, in which a ×4 master reticle is delineated by the electron beam reticle writer, many ×2 working reticles are formed by the first electron reduction projector, and patterns are formed on wafers by the final electron reduction projector. An electron optical column for formation of the working reticle is designed and the aberrations are calculated. For an object-image distance of 600 mm and main- and subfield sizes of 40 and 0.5 mm, respectively, the residual radial and azimuthal distortions are 6.4 and 5.7 nm, respectively, and the beam blur is less than 45 nm for beam semi-angles from 0.06 to 0.25 mrad.
Power Spectral Densities of Temporal Variations of Blood Pressures
Authors: Ohtomo Norio , Kamo Tsutomu , Watanabe Midori , Yoneyama Kimihiro , Tanaka Yukio , Hayashi Ressei
Published: October 2002

A comprehensive study of power spectral densities for time series data of blood pressure measured for four individuals, one healthy subject and three diseased subjects (pure autonomic failure (PAF), PAF complicated with supraventricular premature contraction, and multiple cerebral infarction with atrial fibrillation (Af)), was carried out using the computing program “MemCalc.” The whole spectrum for every time series indicates exponential characteristics until it levels off at a limit determined by the accuracy of the present measurement. The three-dimensional spectral array obtained from segment time series analysis showed a fine array of the fundamental and its harmonic modes, and was concluded to be a powerful tool for medical diagnosis. “Homeostasis” in living bodies is discussed on the basis of the present results. A new link between the nonlinear sciences and basic and/or clinical medicine found in the present study is sure to play an important role in medical diagnosis and prognosis.
Transmission Electron Microscope Observation of “IR Scattering Defects” in As-Grown Czochralski Si Crystals
Authors: Kato Masahiro , Yoshida Tomosuke , Yasuhiro Ikeda Yasuhiro Ikeda , Yutaka Kitagawara Yutaka Kitagawara
Published: October 2002

Grown-in defects detected by IR laser scattering tomography (LSTDs) in Czochralski-grown Si crystals were identified for the first time by transmission electron microscopy (TEM) with a special defect positioning technique. The basic structure of each LSTD was revealed to be a composite of two or three incomplete octahedral voids with a total size of 100–300 nm. The TEM images of the defects suggest the existence of walls several nanometers thick surrounding the voids. A weak oxygen signal was detected from the defect by energy dispersive X-ray spectrometry. The thin walls surrounding the voids were considered to be made of SiOx.
Angle Position Detection Based on Amorphous Silicon Four Quadrant Orientation Detector
Authors: Kang-Cheng Lin Kang-Cheng Lin , Si-Chen Lee Si-Chen Lee
Published: October 2002

Using the amorphous silicon active hollow FOur QUadrant Orientation Detector (FOQUOD) which can be used to determine the contrast edge position of the image of an object and its orientation with respect to a horizontal line, two methods are devised to extract the angular positions of an image. The first method uses a signal processing technique to filter the line orientations and two data filter masks to extract the angular position of an image. The second method is to project a test image onto two active hollow FOQUOD arrays in juxtaposition simultaneously with a small relative shift. Then by comparing the position and orientation values of the corresponding cells, the angular position can be extracted. Both methods achieve an accuracy of over 90%. Based on these two methods, a double FOQUOD device which can be used to determine the angle position is designed and fabricated for the first time. The accuracy of determining the angle positions of an arbitrary feature exceeds 60%.
Effects of Sulfur Passivation of GaSb on the Thermal Stability of Al/n-GaSb Contacts
Authors: Ghader Eftekhari Ghader Eftekhari
Published: October 2002

It is demonstrated that sulfur passivation of GaSb before metal evaporation improves thermal stability of Al/n-GaSb Schottky contacts. The contacts were annealed at 300° C, 400° C, and 500° C for 20 s. In the unpassivated contacts annealed at 500° C barrier height decreased by 180 meV, reverse current increased by a factor of 10, breakdown voltage decreased by a factor of 2.6. In the passivated contacts annealed at 500° C, barrier height decreased by 40 meV, reverse current increased by a factor of 3 and breakdown voltage decreased by a factor of 1.4. Formation of thermally stable S–S, S–Sb, and S–Ga bonds and reduction in the interdiffusion and reaction of elements at the interface were used to explain the observations.
Optimization of a Novel Self-Planarizing Au Metallization Process for Practical VLSI Applications
Authors: Tai-chin Lo Tai-chin Lo , Miu-ying Chan Miu-ying Chan
Published: October 2002

A self-planarizing Au metallization process by selective electrolytic plating was developed for metal interconnections in the submicron range. Problems still remain concerning the simultaneously formation of a large wide gold pattern with submicron features. A `trilevel-resist' filling process was developed in this work to overcome these problems. Moreover, optimization of the selective plating process was achieved. Thickness uniformity of plated gold wires with various dimensions can be maintained at better than 8.4% across 4-inch wafers.
Evaluating Densities and Energy Levels of Impurities with Close Energy Levels in Semiconductor from Temperature Dependence of Majority-Carrier Concentration
Authors: Hideharu Matsuura Hideharu Matsuura
Published: October 2002

By modifying the graphic method proposed in Jpn. J. Appl. Phys. 35 (1996) L555, the author aims to evaluate the densities and energy levels of impurities with two kinds of close energy levels. Using the temperature dependence of the majority-carrier concentration n(T), the function n(T) exp
(E
ref/k
T)/k
T is defined, where k is the Boltzmann constant and E
ref is a newly introduced parameter. The densities and energy levels of the impurities can be evaluated from the peaks of this function. Even in Si with two donors (Sb and P), it is found that the densities and energy levels of the two donors can be evaluated accurately.
Reply to “Comment on `Optical Characterization of Si1-xCx/Si ( 0≤x ≤0.014) Semiconductor Alloys' ”
Authors: Hosun Lee Hosun Lee
Published: October 2002

Based on the previous comment by Zollner et al.., we discuss the possibility that the double feature in the derivative spectra of the dielectric functions of Si1-
x

C

x

/Si (0≤x≤0.014) and Si0.924-
x

Ge0.076C

x

/Si (0≤x≤0.014) alloys grown using solid phase epitaxy may come from interference phenomenon. We emphasize that the argument does not change the main content of our previous reports.
Low Temperature Fabrication of Thin Film Transistors using Microcrystalline Si Deposited by Cathode-Type RF Glow Discharge
Authors: Jayatissa Ahalapitiya Hewage , Hatanaka Yoshinori , Yoichiro Nakanishi Yoichiro Nakanishi , Tomuo Yamaguchi Tomuo Yamaguchi
Published: October 2002

Thin film transistors (TFTs) were fabricated using microcrystalline silicon (µ c- Si) deposited by cathode-type rf glow discharge method at temperature of 400° C. It was found that the µ c- Si TFTs have high mobility compared with amorphous silicon TFTs fabricated at the same temperature region. The results suggest that the present method is also suitable for low temperature fabrication of TFTs because of high mobility and simple modification of glow discharge deposition method.
Electric Field Effect in LaTiO3/SrTiO3 Heterostructure
Authors: Yoshida Chikako , Tamura Hirotaka , Yoshida Akira , Kataoka Yuji , Fujimaki Norio , Yokoyama Naoki
Published: October 2002

We developed a technique to form conductive LaTiO3/SrTiO3 interdiffusion layers with a sheet carrier density in the 1013 cm-2 to 1015 cm-2 range. An LaTiO3/SrTiO3 heterostructure, which showed a field effect, was used as the conductive channel of a superconducting weak link. We also demonstrated that the heterostructure's field effect can be used to control its own electronic conduction characteristics, such as the mobility depth profile.
Current Distribution and Vortex-Vortex Interaction in a Superconducting Film of Finite Thickness
Authors: Wei Jung-Chun , Yang Tzong-Jer
Published: October 2002

The current distribution due to a single vortex in a superconducting film of finite thickness is calculated, based on the London model. At large distances from the vortex core, the current density on the surface of the superconductor was found to follow the 1/r
2 law which has a simple expression, J
s(r, 0)≈φ0[coth
(d/λ)+ csch (d/λ)]/2πµ0λr
2. We also find that the interaction energy between two vortices has the form, U
int(r
12)=φ0
2[H
0(r
12/Λ′)-Y
0(r
12/Λ′)], when the film is not too thick and at large distances between two vortices. This potential differs from Pearl's result by the new effective penetration depth Λ′=2λcoth
(d/λ).
Theoretical Analysis of Effect of Domain Inversion Shape on Second Harmonic Generation Conversion Efficiencies of Quasi-Phase-Matched Nonlinear Optical Waveguide Devices
Authors: Hou Wei Xing , Chong Tow Chong , Kumagai Hirohiko , Hirano Masahiro
Published: October 2002

The effect of domain inversion shape on the SHG conversion efficiencies of QPM nonlinear waveguide devices is theoretically analyzed. Three domain inversion shapes, namely elliptic, sine and arc, are considered in this analysis. The duty cycle α(x) is derived for each case and the periodic modification of the nonlinear coefficient is taken as a binary square function. To simplify the calculation of the integral overlap between the domain-inverted regions and the guided modes, a highly confined mode and a Gaussian mode are used. The SHG conversion efficiencies are theoretically plotted against the duty cycle α0 for various mode width/waist. The results show that the optimal duty cycle α0 for maximum SHG efficiency is shape-dependent. This implies that, in order to obtain large harmonic intensities, it is necessary to identify the domain inversion shape associated with a particular fabrication process before the QPM structure can be optimized by choosing the appropriate grating duty cycle.