bluuebunny/crossref_metadata_2025 huggingface dataset:
Fundamental Research on Mercuryless Fluorescent Lamps II – External Electrode Operation with Pulsed Dielectric Barrier Discharge –
Authors: Masafumi Jinno Masafumi Jinno , Hisayoshi Kurokawa Hisayoshi Kurokawa , Masaharu Aono Masaharu Aono
Published: October 2002

The characteristics of electrodeless xenon discharge fluorescent lamps
using dielectric barrier discharge are described in this paper.
All lamps were operated with pulsed discharge.
The luminance of phosphor increases as the pressure of xenon increases.
As the pressure of xenon increases, the second peak of phosphor
emission increases.
These increases seem to be caused by the VUV light of xenon excimers.
Therefore, in order to obtain high luminance, xenon should be filled at
high pressure.
In the case of the lamp operated by inner electrodes, if only xenon is
contained in the lamp, the cathode is bombarded and is damaged by the
large mass of a xenon ion.
On the other hand, the external electrode type is never damaged by the
ions or electrons.
Moreover, the efficacy of the external electrode type is as great as
the inner electrode type, and it can be improved by increasing the
distance between electrodes.
Analytical Model of Human Body Model Electrostatic Discharge Current Distribution and Novel Electrostatic Discharge Protection Structure
Authors: Shih Jiaw-Ren , Lee Jian-Hsing , Hwang Huey-Liang , Liew Boon-Khim , Chiang Shang-Yi
Published: October 2002

Conventionally, the n-p-n bipolar transistor with a substrate resistor operated in the snapback region has
been the basic model used to explain the discharge behavior of a lightly doped drain (LDD) N-channel metal-oxide semiconductor (NMOS) transistor under a positive human-body model (HBM) electrostatic discharge
(ESD) zapping event. However, this simple model ignores the geometry effect by the P-well pick-up position
and does not explain the current-crowding effect. In this paper, a new transmission-line equivalent-circuit model
with the equal-potential-region (EPR) formation is proposed to study the ESD zapping current distribution. The
simulation result shows that maximum current density is in the region near the P-well pick-up, which
corresponds to the damage sites determined by failure analysis. Based on this new model, a novel protection
structure with P+ diffusion in each source region is proposed to improve current uniformity, which is verified to
have an excellent ESD failure threshold. In addition, from the measurement of real-time current–voltage (I–V)
characteristics during ESD zapping, a phenomenon called the self-biasing Effect is observed. When the effective
substrate resistance decreases, the device's snapback voltage will inherently increase to generate more impact
ionization current so as to sustain a sufficient substrate potential to keep the bipolar turned on. However, this
V
sp increase will not necessarily lead to a lower ESD failure threshold.
Silicon Quantum Dot in a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) Structure
Authors: Khoury Maroun , Gunther Allen , Jr. David P. Pivin , Rack Mary Jo , Ferry David K.
Published: October 2002

We have fabricated a 200 nm quantum dot in a silicon Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) structure. Confining gates situated on top of a 10 nm oxide deplete the electron gas created by an inversion gate 70 nm away from the Si-SiO2 interface. Measurements indicate that the size of the dot can be tuned by the gates. Furthermore, we observe conductance fluctuations in the gate characteristic which are indicative of single-electron behavior.
Recovery of (411)A Superflat Interfaces in GaAs/Al0.3Ga0.7As Quantum Wells Grown on (411)A GaAs Substrate by Molecular Beam Epitaxy
Authors: Shinohara Keisuke , Shimizu Yasuyuki , Shimomura Satoshi , Hiyamizu andSatoshi
Published: October 2002

The recovery of (411)A superflat interfaces in a GaAs/Al0.3Ga0.7As quantum well (QW) grown on a (411)A GaAs substrate by molecular beam epitaxy (MBE) has been investigated. The (411)A superflat interfaces can be realized only under a low V/III ratio (V/III = 7) and the flatness of the interfaces degrades under a condition of a high V/III ratio (V/III = 14). When the V/III ratio was changed during MBE growth of a lower Al0.3Ga0.7As barrier layer from 14 to 7 at only 2 nm below the lower (GaAs-on-AlGaAs) interface of the QW with a well width of 1.8 nm, the linewidth of the photoluminescence peak from the QW became as small as that of a 1.8 nm GaAs/Al0.3Ga0.7As QW with (411)A superflat interfaces. This result indicates that if only a 2-nm-thick Al0.3Ga0.7As layer were grown with V/III = 7 on the rough surface of an Al0.3Ga0.7As layer formed with V/III = 14, the (411)A superflat surface would be formed. This technique could be useful in fabricating GaAs/Al0.3Ga0.7As resonant tunneling diodes with (411)A superflat interfaces, which have good n-type GaAs contact layers obtained with V/III ≥14 on the (411)A GaAs substrate.
Clustering and Transient Enhanced Diffusion of B Doping Superlattices in Silicon
Authors: Uematsu Masashi
Published: October 2002

We have simulated the clustering and transient enhanced diffusion (TED) of
boron profiles with superlattice structures. Using an analytical formula
for B clustering in terms of the reaction between B atoms and
supersaturated self-interstitials, we have satisfactorily fitted B TED
profiles not only in the implantation-damaged regions but also deep in the
bulk. In the simulation, we have also assumed TED reduction by C diffusion
and self-interstitial trapping.
Lifetime of Confined LO Phonons in Quantum Dots and Its Impact on Phonon Bottleneck Issue
Authors: Xin-Qi Li Xin-Qi Li , Hajime Nakayama Hajime Nakayama , Yasuhiko Arakawa Yasuhiko Arakawa
Published: October 2002

Due to the anharmonicity of lattice forces, the confined LO
phonon in semiconductor quantum dots decays into bulk acoustic phonons,
which results in a weakly size-dependent finite lifetime of the LO phonons
with a time scale of picoseconds.
Noting that this time scale is much shorter than the typical carrier
radiative recombination time of nanoseconds,
we expect an interesting impact of the LO phonon decay on the carrier's
energy relaxation in quantum dots, where the phonon bottleneck effect
was predicted.
Accordingly, by including the dissipative decay of the LO phonons
and employing the Wigner-Weisskopf approach, we re-examine theoretically
the bottleneck issue within an intrinsic phonon scattering mechanism.
The calculated result shows a fast carrier relaxation rate
higher than 1010 s-1
in a wide detuning range of tens of meV around the LO phonon energy,
which differs significantly from the original phonon bottleneck prediction.
Spin-Valve Heads for 20 Gbit/inch2 Recording
Authors: Morinaga Akira , Shiiki Kazuo
Published: October 2002

Spin-valve (SV) heads with antiferromagnetic control layers for
20 Gbit/inch2 recording were designed by solving the
Landau-Lifshitz-Gilbert equation. The calculated SV-head model has a
read track width of 500 nm and a detected minimum bit length of about
50 nm recorded on a medium whose thickness, t
mag, is
14 nm, and the product of remanent flux density, B
r, and
thickness, t
mag, is 50 Gµm. The head-to-medium spacing
is 30 nm. When the sensing-current density is less than about
5.0×107A/cm2, the thickness of the
pinning layer and the free layer is appropriate to be 2.0 nm and
3.0 nm, respectively. The resolution,
V
high/V
low, is about 0.67 when the optimum
shield gap length, G, is 80 nm. The resolution depends on the
sensing-current density, J, as well as the gap length G. We
obtained a low-density output voltage of
700 µVp-p, which is practically applicable, by
selecting the optimum element size.
High Power Operations of 980 nm Ga0.8In0.2As/GaxIn1-xAsyP1-y/Ga0.51In0.49P/GaAs Pump Lasers Prepared by Multi-step Metalorganic Vapor Phase Epitaxial Growth with Ion Implanted Channels
Authors: Jang Dong Hoon , Lee Jung Kee , Cho Kyung HyunPark , Nam Eun Soo , Shim Chul SoonPark , Jeong Ji Chai , Park Ki TaeJeong
Published: October 2002

The silicon (Si) or boron (B) implantation process in
Ga0.8In0.2As/Ga
x
In1-x
As
y
P1-y
/Ga0.51In0.49P/GaAs
quantum well structures can be used not only for maintaining
single lateral mode during high power operation but also for
increasing the catastrophic optical damage (COD) level of 980 nm pump
lasers. The fabricated 980 nm pump lasers with partially ion
implanted channels after ridge waveguide structure formation exhibited
high power operation up to 250 mW without any kink and
beam steering. A photoluminescence peak shift of 70 meV was
obtained by 120 keV Si-implantation and annealing at
900°C. Improvement of the COD level by
a minimum of 1.65 times is obtained by forming transparent windows
near facets
by Si implantation and annealing. A highly nonradiative polycrystalline phase of the active area may be the major cause of COD failure in the Al-free 980 nm lasers.
Characterization of Amorphous Phases of Ge2Sb2Te5 Phase-Change Optical Recording Material on Their Crystallization Behavior
Authors: Park Jeongwoo , Kim Myong R. , Choi Woo S. , Seo Hun , Yeon Cheong
Published: October 2002

The difference in crystallization behavior between the as-deposited amorphous state and the melt-quenched amorphous state of Ge2Sb2Te5 alloy has been studied using a dynamic tester. The melt-quenched amorphous alloy showed much shorter crystallization time than did the as-deposited one. We laser-annealed the as-deposited amorphous alloy under a certain condition so as to make it exhibit the same crystallization property as that of the melt-quenched one. The crystallization kinetics of this laser-annealed amorphous alloy and the as-deposited amorphous alloy has been explained by applying transmission electron microscopy (TEM) and continuously heating the specimens in a differential scanning calorimeter (DSC). From the TEM results, it has been shown that preexisting atomic clusters accelerate the crystallization speed of the amorphous alloy. The two states have been found to have different crystallization temperatures and activation energies.
Analysis of GaInAsP Surfaces by Contact-Angle Measurement for Wafer Direct Bonding with Garnet Crystals
Authors: Yokoi Hideki , Mizumoto Tetsuya , Shimizu Masafumi , Futakuchi Takashi Waniishi Naoki , Kaida Noriaki , Nakano Yoshiaki
Published: October 2002

GaInAsP surfaces with various treatments were analyzed by contact-angle
measurement for wafer direct bonding between GaInAsP and garnet crystals. The contact
angle of a water droplet was measured to estimate the hydrophilicity of the wafer
surfaces. The most hydrophilic surface was obtained after an O2 plasma activation
process. Direct bonding was successfully achieved between GaInAsP activated by O2
plasma and garnet crystals.
A Photorefractive Setup for Parallel Not-OR and Not-AND Operations with Mutually Incoherent Light
Authors: Cheng Nai-Jen , Lee Hsiao-Yi , Yau Hon-Fai , Kung Hong-Chang
Published: October 2002

We have demonstrated experimentally that optical Not-OR (NOR) and Not-AND (NAND)
operations can be done with a single setup. The setup is capable of processing parallel
inputs. Two barium titanate (BaTiO3) crystals are used in the setup and photorefractive
effects are employed. Instead of using the interference between the two input signals to
be processed or the so called local incoherent erasing, the setup works on the
phenomenon of self-pumped phase conjugation and the suppression of it by the input
signals in ordinarily polarized state. In this way, the two input
channels can be mutually incoherent.
Coulomb Blockade Observed in InAs/AlGaSb Nanostructures Produced by an Atomic Force Microscope Oxidation Process
Authors: Shigehiko Sasa Shigehiko Sasa , Takatoshi Ikeda Takatoshi Ikeda , Kazutomo Anjiki Kazutomo Anjiki , Masataka Inoue Masataka Inoue
Published: October 2002

We fabricated and characterized an InAs/AlGaSb single electron
transistor produced by the atomic force microscope (AFM) oxidation process.
The structure of the transistor we developed has two in-plane gate electrodes
which are separated from the current channel by a 0.1-µm-wide gap
defined by AFM
oxidation and selective GaSb/AlGaSb and InAs etching processes.
A complete transistor operation, including clear pinch-off characteristics is
achieved by applying negative gate voltages at 4.2 K. Near the pinch-off,
an island is formed in the middle of the InAs channel by depleting narrow
InAs constrictions fabricated on both sides of the island. We observed a
Coulomb gap of 1.6 mV, which is consistent with the estimated self-capacitance of
the island. The oscillatory behavior in the I–V characteristics suggests a
contribution of quantum effects to the electron tunneling process.
Crystal Structure and Ionic Conductivity in Bi2O3-Rich Bi2O3–Ta2O5 Sintered Oxides
Authors: Saito Takashi , Miida Rokuro
Published: October 2002

Aside from the already known fluorite phase in
(Bi2O3)1-x
(Ta2O5)
x
with 0.18≦x≦0.25,
a second fluorite phase was found in heated samples
(800°C) with x≦0.07 and quenched samples with
0.05≦x≦0.07; we called these two phases F I and F II,
respectively. The decrease in conductivity with increasing x at
temperatures between 650°C and 800°C was classified
into three degrees, (i) low, (ii) medium and (iii) high corresponding
to F II, F I + F II and F I zones, respectively. The appearance of
these degrees was explained in terms of the growth of low-conductivity
F I domains within the high-conductivity F II matrix. The sample held
at 630°C, 600°C or 550°C after slow cooling
from 800°C showed a gradual decrease in conductivity
depending on the holding temperature, and this phenomenon was
interpreted by relating the growths of γ-Bi2O3-type
structure (630°C and 600°C) and α-and
β-Bi2O3-type structures (550°C).
Copper Chemical Vapor Deposition Films Deposited from Cu(1,1,1,5,5,5-hexafluoroacetylacetonate) vinyltrimethylsilane
Authors: Lin Pi-Jiun , Chen Mao-Chieh
Published: October 2002

Copper chemical vapor deposition (Cu CVD) from Cu(hfac)vinyltrimethylsilane was studied using a low pressure chemical vapor deposition (LPCVD) system of a cold-wall vertical reactor. It was found that the resistivity of the chemical vapor deposited
Cu films was dependent on the film's microstructure and impurity content, which in turn
were dependent on the deposition conditions. Using H2 as the carrier gas, we were able
to deposit Cu films of low impurity content at deposition rates as high as 150 Å/min.
The lowest resistivity Cu films can be deposited at a temperature of 180°C and a
pressure of 300 mTorr.
Properties of Ru and RuO2 Thin Films Prepared by Metalorganic Chemical Vapor Deposition
Authors: Chul Choi Young , Soo Lee Byung
Published: October 2002

Ru and RuO2 thin films were deposited on Si substrates, using a metalorganic precursor of ruthenium carbonyl [Ru3(CO)12], by metalorganic chemical vapor deposition (MOCVD), and their properties were investigated. Ru or RuO2 single phase could be obtained by controlling the flow rate of the oxidant gas (O2). When the Ru film was annealed in oxygen atmosphere, oxygen atoms diffused through the Ru layer, resulting in the oxidation of ruthenium. The compositional uniformity of RuO2 thin films in the thickness direction was good, and interdiffusion at the interface between RuO2 and Si was not observable even after the post-annealing process. The deposition rate of RuO2 thin films is highest at 550°C. All RuO2 thin films showed a dense and smooth microstructure. It was demonstrated that a larger grain size of the film resulted in lower resistivity, and that post-annealing decreased the resistivity. The larger the grain size of the RuO2 film, the greater is the decrease in resistivity by annealing.
Different Growth Modes of Al on Si(111)7 ×7 and Si(111)√3×√3–Al Surfaces
Authors: Yoshimi Horio Yoshimi Horio
Published: October 2002

Initial growth modes of Al atoms on Si(111)7 ×7 and on Si(111)√3×√3–Al surfaces were clarified by energy-filtered reflection high-energy electron diffraction (EF-RHEED). The growth experiments were carried out at room temperature with a deposition thickness up to about 15 Å. The EF-RHEED patterns and the intensity oscillation curves of the reflection beams were observed under the condition of the energy loss threshold E
loss=30 eV of the retarding potential in order to decrease the background intensity. It was found that, in the case of the Al/Si(111)7 ×7 system, Al atoms grow as three-dimensional islands with the orientations Al(001) ∥Si(111) and Al[110] ∥Si[110] accompanying a twelvefold symmetry axis due to the combination of the fourfold symmetry [Al(001) deposition plane] and threefold symmetry [Si(111) substrate surface]. However, in the case of the Al/Si(111)√3×√3–Al system, Al atoms exhibit an almost two-dimensional layer-by-layer growth mode with Al(111) ∥Si(111) and Al[110] ∥Si[110]. In the latter case, a newly proposed entirely filled T4 site (EFT) surface structure in the transient growth stage is expected to play an important part in achieving excellent epitaxial growth of Al(111).
Measurement of Contact Potential of GaAs pn Junctions by Kelvin Probe Force Microscopy
Authors: Mizutani Takashi , Usunami Takao , Kishimoto Shigeru , Maezawa Koichi
Published: October 2002

The contact potential of GaAs pn junctions was measured by Kelvin probe force microscopy (KFM). The contact potential profile of the pn junctions was not clear in the case of no illumination. When the sample was illuminated with a microscope light, the potential profile reflecting pn junctions became clear. The observed surface potential was explained by taking the surface band bending due to surface states into account.
Oxygen Microwave Plasma Density Enhancement by Surface Waves with a High-Permittivity Material Window
Authors: Furukawa Masakazu , Koromogawa Takashi , Kamiyo Kouji , Shinagawa Keisuke , Kawamura Katsufumi , Shindo Haruo
Published: October 2002

The oxygen microwave plasma properties caused by surface
waves in high-permittivity materials of alumina and quartz
windows were studied for large-diameter plasma generation. The
electron density value for the alumina window at microwave powers
above 450 W is significantly enhanced by surface waves and is
considered to be in a surface-wave mode. The electron density
value for the quartz window at powers above 250 W is also in the
surface-wave mode. In the surface-wave mode, the electron
temperature values are lower than those in the volume mode which
is not affected by surface waves, and the intensity values of the
built-in high-frequency magnetic field decrease rapidly at a
distance of 7–10 cm from the bottom surfaces of the windows.
Plasma emission modes for the alumina window are in the (0,1)
mode at low pressure (13.3, 33.9 Pa) and the multiple mode at
high pressures (66.5, 133 Pa). On the contrary, plasma emission
modes for the quartz window are in the multiple mode at high
pressures and the (0,1) mode at low pressures. Uniformity of
the plasma density distribution in the multiple mode is better
than that in the (0,1) mode at identical pressures.
Electrical Properties of a Periodic Porous Carbon Replica of Opal
Authors: A. Zakhidov Katsumi Yoshino , H. Baughman Ray
Published: October 2002

The electrical conductivity and magnetoconductance of pyrolized porous phenolic resin opal replicas have been studied as a function of their heat treatment temperature (HTT) up to 2380°C. Porous graphite can be formed by pyrolizing the phenolic resin opal replica. In the case of replicas with a low HTT, a crossover from Mott variable range hopping (VRH) to Efros and Shklovskii VRH upon decreasing the temperature has been experimentally observed. For those with a high HTT, the electrical properties are consistent with those of pyrolytic graphite. The occurrence of positive magnetoconductance indicates the existence of quantum effect at low temperatures.
Measurement of Parameters for Simulation of 193 nm Lithography Using Fourier Transform Infrared Baking System
Authors: Sekiguchi Atsushi , Isono Mariko , Matsuzawa Toshiharu
Published: October 2002

By incorporating baking equipment into a Fourier transform infrared (FT-IR) spectrometer, a
deprotection reaction parameter measurement system that can be used with chemically amplified
resists has been developed. This system allows us to study new models for chemically amplified
(CA) resists by including into a conventional deprotection reaction model an initial delay effect and
a quencher effect. This model is also used to measure deprotection reaction parameters. The
parameters thus obtained are inputted into a lithography simulator PROLITH/2 to perform profile
simulations. The results are compared with those of scanning electron microscope (SEM)
observations. Although the simulation results and SEM observations are not in complete agreement,
the general trends observed are in adequate agreement. These results confirm the applicability of
the proposed model to CA resists for ArF excimer laser lithography and verify the usefulness of the
measurement system.
Picosecond Pulsed X-Ray Diffraction from a Pulsed Laser Heated Si(111)
Authors: Hironaka Yoichiro , Tange Tomoyuki , Inoue Tomoharu , Fujimoto Yasushi , Nakamura Kazutaka G. , Kondo Ken-ichi , Yoshida Masatake
Published: October 2002

Transient lattice expansion of a Si(111) crystal induced by pulsed laser heating is studied by the picosecond pulsed X-ray diffraction. The X-rays used are laser induced X-rays with a pulse duration of 6 ps. The lattice expansion at 3 ns after laser heating is estimated to be about 1×10-3 Å from the observed shift of Bragg angles, which is in good agreement with the numerical calculations of the temperature distribution and the heat transport analysis.
A High-Temperature Thermodynamic Model for Metalorganic Vapor Phase Epitaxial Growth of InGaN
Authors: Ou Jehn , Pan Yung-Chung , Lee Wen-Hsiung , Shu Chen-Ke , Lin Heng-Ching , Lee Ming-Chih , Chen Wen-Hsiung , Chiang Chung-I , Chang Horng , Chen Wei-Kuo
Published: October 2002

A thermodynamic analysis tailored with a high-temperature parameter was performed for metalorganic vapor phase epitaxial (MOVPE) growth of In
x
Ga1-x
N alloys. Accordingly, a series of InGaN samples were prepared under various input In flow rates and growth temperatures. Theoretical results indicate that the In solid concentration tends to increase with increasing In flow rate and with decreasing temperature, whereas the metal droplets form more easily on the surface at lower growth temperatures and higher In fluxes, which are in good agreement with our experimental data.
Cu(InGa)Se2 Thin-film Solar Cells with High Resistivity ZnO Buffer Layers Deposited by Atomic Layer Deposition
Authors: Sutichai Chaisitsak Sutichai Chaisitsak , Takeshi Sugiyama Takeshi Sugiyama , Akira Yamada Akira Yamada , Makoto Konagai Makoto Konagai
Published: October 2002

The aim of our experiments is to improve the performance of Cd-free ZnO/Cu(InGa)Se2 solar cells using a high-resistivity ZnO buffer layer. Buffer layers were deposited by atomic layer deposition (ALD) using diethylzinc (DEZn) and H2O as reactant gases. The structural and electrical properties of the ZnO films on glass substrates were characterized. A high resistivity of more than 103 Ω·cm and a transmittance of above 80% in the visible range were obtained. We focused on determining the optimum deposition parameters for the ALD-ZnO buffer layer. Results indicate that the thickness and resistivity of the ALD-ZnO buffer layer, as well as the heat treatment prior to the deposition of the buffer layer, affect the device characteristics. The best efficiency obtained with an ALD-ZnO buffer layer of solar cells without an antireflective coating was 12.1%. The reversible light soaking effect was observed in these devices.
Effect of Surface Quality on Overgrowth of Highly Strained GaInAs/GaAs Quantum Wells and Improvement by a Strained Buffer Layer
Authors: Schlenker Dietmar , Pan Zhong , Miyamoto Tomoyuki , Koyama Fumio , Iga Kenichi
Published: October 2002

The introduction of a thin strained GaInAs buffer layer is proposed in the metalorganic chemical vapor phase
deposition of GaInAs/GaAs quantum wells for ≥1.2 µm wavelength emission. This buffer layer is found to be
very effective in improving the surface quality on which highly mismatched GaInAs quantum wells with an
indium content around 40% are grown. Atomic force microscopy measurements demonstrate that the insertion of
this strained GaInAs buffer layer can reduce the density of three dimensional islands in a highly strained GaInAs
layer by one order of magnitude. We show that highly strained GaInAs/GaAs quantum wells with an indium
content around 40% are more sensitive to surface quality than in the case of a lower indium content. This
technique has enabled us to achieve a high-quality GaInAs/GaAs quantum well laser emitting at a wavelength
near 1.2 µm.
Significant Effects of As Ion Implantation on Si-selective Epitaxy by Ultrahigh Vacuum Chemical Vapor Deposition
Authors: Furukawa Taisuke , Nakahata Takumi , Maruno Shigemitsu , Tokuda Yasunori , Satoh Shinichi
Published: October 2002

The relation between As ion implantation and Si-selective epitaxy is investigated, taking
account of the application of ultrahigh vacuum chemical vapor deposition to LSI devices. For a
non-implanted wafer, undesirable island-like growth occurred because oxygen was introduced
into the Si substrate by previous etching processes. The implantation of a sufficient dosage of
As ions restored layer-by-layer growth with excellent surface morphology, which is explained in
terms of the removal of the disturbed layer by the additional sputtering effect of ion implantation.
Conformal Step Coverage and Trench Filling of Liquid Phase Oxide Deposition
Authors: Lee Ming-Kwei , Yang Ching-Nan , Lin Ching-Hsing
Published: October 2002

The low-temperature and selective growth in liquid phase deposition of silicon dioxide (LPD-SiO2) makes it suitable for many interesting applications in integrated circuit (IC) fabrications, such as trench isolation, and completely planarized multilevel interconnections. In this paper, the potential of LPD-SiO2 conformal step coverage and trench filling is demonstrated.
Tl2Ba2Ca2Cu3O10 Bulk Samples Prepared by Hot Isostatic Press Method
Authors: Hu Xing , Jia Yu , Xin Ying , Wong K. W.
Published: October 2002

The hot isostatic press method was used to prepare Tl2Ba2Ca2Cu3O10 bulk samples.
Samples with a high mass density were obtained. It was shown that in such prepared
samples most superconducting grains are compressed closely together, thus improving
the weak links between grains and resulting in a higher transport critical current
density.
Effects of Spectral Broadening and Cross Relaxation on the Gain Saturation Characteristics of Quantum Dot Laser Amplifiers
Authors: Yoshihiro Nambu Yoshihiro Nambu , Akihisa Tomita Akihisa Tomita , Hideaki Saito Hideaki Saito , Kenichi Nishi Kenichi Nishi
Published: October 2002

Spectral broadening and cross relaxation of an aggregate of highly carrier-injected quantum dots have been studied experimentally by evaluating the gain saturation and optical-wave mixing characteristics of traveling-wave laser amplifiers that include self-assembled 0.98-µm InGaAs dots. Measured signal-gain spectra at room temperature showed that the gain decreases over the entire gain spectra when an intense and narrow-linewidth saturating signal is injected at a higher-order subband transition of the quantum dot. Differential-gain spectrum was calculated from the saturated and unsaturated signal gain spectra, and revealed asymmetric gain saturation with respect to the wavelength of the saturating signal. These results suggest that cross relaxation is so fast that the dot aggregate has a homogeneously broadened gain spectrum. Self-saturation and cross-saturation characteristics, and the detuning characteristics of highly nondegenerate four-wave mixing were also investigated. The latter revealed that the characteristic times of two cross-relaxation processes are about 1 ps and 100 fs.
Discharge Stability and Performance of a Small-Bore, Fast-Axial-Fow CO2 Laser Using New Pin Anodes
Authors: Tan Mindea , Tou Teckyong , Siew Weeong , Low Kumsang
Published: October 2002

The output performance of a small-bore, fast-axial-flow CO2
laser was investigated and different anode configurations which all
employed a 3 mm discharge pin were compared. It was found that a
simple washer attached to the pin enhanced the discharge stability and
enabled the input power to be increased, and hence the peak laser
output power. An additional perforated plate improved the flow radial
uniformity, thus raising the laser output slope efficiency. The
effects of the washer on the discharge stability and the laser output
performance were largely explained by the measured voltage-currrent
characteristics.
Photoluminescence Related to the Interaction between Carriers and Structural Defects in ZnTe Crystals
Authors: García Jose Angel , Remón Angel , Muñoz Vicente , Triboulet Robert
Published: October 2002

High-quality bulk ZnTe single and polycrystals grown by the cold travelling heater method (CTHM) have been studied by photoluminescence (PL). Single crystals have been deformed in order to create structural defects and dislocations. The PL spectra of these deformed samples present the so-called Y1 and Y2 bands and an emission at 598–604 nm which has not been observed in nondeformed single crystals. This last band presents variations of the intensity as a function of the illumination time. The behaviour and analysis of the bands in the deep-level region indicate the existence of centres that likely produce a reduction in the carrier mobility. These centres can drastically degrade the properties of the material, hampering its use in optoelectronic devices or as a substrate for epitaxy.
Resistance to Tracking and Erosion of Silicone Rubber Material under Various Types of Precipitation
Authors: Wang Xinsheng , Yoshimura Noboru
Published: October 2002

Environment stress and contaminants have become more and more
severe due to the development of industry. Outdoor polymer insulating
materials in use may suffer from rainwater containing various chemical
contaminants so that their resistance to tracking degrades. In this
paper, the tracking resistance of high-temperature vulcanized silicone
rubber (HTVSR) under various types of precipitation is evaluated by
the incline-plane method, using artificial rainwater as a
contaminant. The influences of ion concentration, acidity, and
conductivity of rainwater on the energized silicone rubber material
are studied. Experimental results reported here show that the
degradation of the energized material increases with the ion
concentration of the rainwater; the discharge current and the erosion
of material increase. The conductive ions in rainwater could induce
more tracking and discharge on the energized material surface, and
acidic rainwater could accelerate the electrolyte process in the
materials and dissolve the inorganic filler in silicone
rubber. Although silicone rubber degrades under our process of
accelerated aging using artificial rainwater, the ion concentration,
acidity and conductivity of actual precipitation is insufficient to
exert a significant degradation effect on silicone rubber. Silicone
rubber can resist the erosion of even the most corrosive rainwater and
does not fail.
Structure and Photoelectrochemical Properties of Laminated Monoparticle Layers of CdS and ZnS on Gold
Authors: Nakanishi Takuya , Ohtani Bunsho , Uosaki Kohei
Published: October 2002

Monolayers of CdS and ZnS nanoparticles and their layer-by-layer composite films were fabricated on a gold substrate that was precoated with a self-assembled monolayer (SAM) of 1,6-hexanedithiol. Semiconductor nanoparticles (∼4 nm in diameter) were prepared in reversed micelles. Evidence for the attachment of nanoparticles on SAM was obtained by X-ray photoelectron spectroscopy. A photoinduced anodic current was observed when the semiconductor nanoparticle electrodes were immersed in an electrolyte solution containing triethanolamine as the electron donor. The photocurrent action spectra of nanoparticle monolayers were in good agreement with the absorption spectra of nanoparticle dispersions before immobilization, indicating that the nanoparticles were immobilized on the substrate without changing their particle size. Layer-by-layer composite films of CdS and ZnS showed photoresponse depending on the order of accumulation. This indicates the successful fabrication of a layer-by-layer structure that affects the electron transfer through nanoparticles and the penetration of the electrolyte solution.
Synthesis and Properties of Semiconducting Iron Disilicide β-FeSi2
Authors: Kakemoto Hirofumi , Makita Yunosuke , Sakuragi Shiro , Tsukamoto Takeyo
Published: October 2002

Beta-iron disilicide β-FeSi2 bulk crystals were prepared by a horizontal gradient freeze
method. The grown β-FeSi2 bulk crystals were characterized by structural, electrical and optical
measurements. The β-FeSi2 single phase was determined by X-ray diffraction measurements.
The electrical resistivity of β-FeSi2 increased exponentially with decreasing temperature. From
optical absorption spectra that were obtained from transmittance measurements, the energy band
gap was determined to be 0.85 eV. The refractive index, extinction coefficient and dielectric
constants were calculated using optical reflectance spectra by Kramers-Kronig analysis. In
addition to β-FeSi2 bulk materials, β-FeSi2 films were prepared on Si(100) substrates by a laser
ablation method using the above β-FeSi2 bulk crystals as target materials. Strong Raman signals
from the β-FeSi2 films were observed at 171 cm-1, 190 cm-1, 199 cm-1 and 247 cm-1, indicating
deposition of well-oriented high-quality films. The optical absorption coefficient at 1.0 eV and
energy band gap were determined to be 1.99×
105 cm-1 and 0.85 eV, respectively.
Amplitude and Phase Signals of the Photothermal Deflection Images
Authors: Toshio Kawahara Toshio Kawahara , Masahiko Miyazaki Masahiko Miyazaki , Yoichi Okamoto Yoichi Okamoto , Jun Morimoto Jun Morimoto , Toru Miyakawa Toru Miyakawa
Published: October 2002

Noncontact photothermal deflection (PTD) techniques are applied to the nondestructive photothermal detection of buried structures. The data are analyzed to take account of the finite radius of the excitation laser. The calculated PTD signals and the experimental data are compared. The modulation frequency dependence of both the PTD amplitude and phase signals has been used to estimate the thermal diffusivity. The phase spectra are more sensitive to the buried structure in the deep interior than the amplitude signals and are able to show the sharp edge at the corner of a buried structure. The case where the laser radius is larger than the buried structure is also investigated using fine cross pattern samples.
Surface Observation of a Potassium-Doped C60 Thin Film by Scanning Tunneling Microscopy
Authors: Hirotaka Hosoi Hirotaka Hosoi , Satoru Nagashima Satoru Nagashima , Eiji Hatta Eiji Hatta , Kazuhisa Sueoka Kazuhisa Sueoka , Kōichi Mukasa Kōichi Mukasa
Published: October 2002

Using scanning tunneling microscopy (STM) and X-ray diffraction (XRD) studies, we find that a 500-nm-thick K
x
C60 (x=3) thin film deposited on a gold thin film grown on a mica substrate has the face-centered cubic (fcc)-(311) surface and that a K
x
C60 (x=4) film of the same thickness has the body-centered tetragonal(bct)-(112) surface. The potassium density x of a K
x
C60 thin film is estimated by in situ measurement of the exposure time dependence of the sheet resistance of the film in potassium vapor. STM images of the K3C60 thin film, which are different from the reported images of C60 thin films, indicate that the observed surface is a fcc-K3C60 (311) surface. The images also show that the lattice constant of the potassium-doped C60 thin film is about 0.5% larger than that of a nondoped one along <011>. From the I–V characteristics of the K
x
C60 films as measured by STM, it is found that the band gap of films vary with the value of x in K
x
C60 films.
Structure of Low-Frequency Helium Glow Discharge at Atmospheric Pressure between Parallel Plate Dielectric Electrodes
Authors: Fumiyoshi Tochikubo Fumiyoshi Tochikubo , Takuma Chiba Takuma Chiba , Tsuneo Watanabe Tsuneo Watanabe
Published: October 2002

Atmospheric-pressure helium glow discharge at 100 kHz between parallel plate dielectric electrodes is studied experimentally and theoretically. Experimental work was carried out by spatiotemporal optical emission spectroscopy to examine the behavior of electrons. The emission from helium atoms revealed the behavior of high-energy electrons (above 22 eV), while the emission from the second positive band of nitrogen revealed the behavior of medium-energy electrons (11–20 eV). Theoretical work was carried out using a one-dimensional fluid model with local field approximation under the same discharge conditions as the experimental one. It was clarified that i) the discharge structure is essentially the same as that in low-pressure glow discharge, ii) ionization by secondary electrons from the cathode is essential for sustaining the discharge, and iii) ionization occurs at low electric field (about 30 Td). This last property is important for conducting “moderate” ionization for stable glow discharge at atmospheric pressure in the absence of localized discharge columns.
Plasma Absorption Probe for Measuring Electron Density in an Environment Soiled with Processing Plasmas
Authors: Kokura Hikaru , Nakamura Keiji , Ghanashev Ivan P. , Sugai Hideo
Published: October 2002

In this paper, we describe a novel and simple technique for measuring electron density using a plasma absorption probe (PAP). PAP enables us to measure the local absolute electron density even when the probe surface is soiled with processing plasmas. The technique relies on the resonant absorption of surface waves (SWs) excited in a “cavity” at the probe head. The PAP consists of a small antenna connected with a coaxial cable and is enclosed in a tube (dielectric constant ε) inserted in a plasma (electron plasma frequency ωp). A network analyzer feeds a rf signal to the antenna and displays the frequency dependence of the power absorption. A series of resonant absorptions are observed at frequencies slightly above the SW resonance frequency, ωSW = ωp/(1+ε)1/2, which allows us to determine the electron density. The measured electron densities are in good agreement with the data obtained by the plasma oscillation method.
Highly Selective Etching of Poly-Si by Time Modulation Bias
Authors: Ono Tetsuo , Miyazaki Hiroshi , Mizutani Tatsumi , Goto Yasushi , Kure Tokuo
Published: October 2002

Highly selective etching of poly-Si is possible by time modulation (TM) bias. Radio frequency (RF) bias applied to a substrate is pulse modulated. The energy of ions impinging on the wafer is varied by the peak-to-peak voltage of RF bias. The average flux of accelerated ions is controlled by the duty ratio of the pulse. The selectivity of poly-Si to SiO2 is about 1.5-fold that of continuous wave bias at a poly-Si etch rate of 100 nm/min. The SiO2 etch rate is suppressed and the selectivity increased, this may be caused by the selective deposition of reaction products including oxygen on the SiO2 surface during off periods of RF bias.
Low-Pressure Measurement Using an Ultrasonic Sensor II
Authors: Ishikawa Toshiaki
Published: October 2002

Pressure dependence of ultrasonic signals transmitted through an area evacuated over the range of 13 Pa to atmospheric pressure was found to show a linear relationship in a log
–log
plot, in which a bend appears at around 103–104 Pa. The cause of the bend was not clear. A treatment including the absorption of ultrasonic waves into the medium in the evacuated area was applied to the analysis. A least squares fitting of the equation obtained to the experimental results showed good agreement, and the absorption coefficient obtained from the fitting parameters gave a reasonable value.
Evaluation of Self-Patterned PbZrxTi1-xO3 Thin Film from Photosensitive Solution
Authors: Uozumi Gakuji , Kageyama Kensuke , Atsuki Tsutomu , Soyama Nobuyuki , Uchida Hiroto , Ogi Katsumi
Published: October 2002

Micro-patterned PZT(20/80) films were fabricated on Pt/Ti/SiO2/Si substrate from a photosensitive solution by the sol-gel process. A coated film was exposed to UV rays (365 nm) at an intensity of 570 mJ/cm2 and developed with a 1:1 mixture of 2-methoxyethanol and isopropyl alcohol. The 170-nm-thick film with a smooth surface showed P
r of 31.9 µC/cm2 and E
c of 120.8 kV/cm. Films with smoother surface morphology and better electrical properties than conventional PZT films were obtained by this process.
Preparation of Pb(Zr, Ti)O3 Thin Films by Plasma-Assisted Sputtering
Authors: Hioki Tsuyoshi , Akiyama Masahiko , Ueda Tomomasa , Onozuka Yutaka , Suzuki Kouji
Published: October 2002

A novel plasma-assisted RF magnetron sputtering system with an immersed coil
antenna between a target and a substrate was applied for preparing Pb(Zr, Ti)O3 (PZT)
thin films. The antenna enabled the generation of inductively coupled plasma (ICP)
independently of the target RF source. The plasma assisted by the antenna resulted in the
changes of ion fluxes and these energy distributions irradiating to the substrate. The
crystalline phase of the deposited PZT thin films was occupied by the perovskite phase
depending on the antenna power. In addition, a high deposition rate, modified uniformity
of film thickness, and a dense film structure with large columnar grains were obtained as a
result of effects of the assisted plasma. The application of the plasma-assisted sputtering
method may enable the preparation of PZT thin films that have
excellent properties.
Chemical Solution Processing and Characterization of La Doped Tungsten Bronze K0.4(Pb0.6Ba0.4)0.8Nb2O6 Thin Films
Authors: Sakamoto Wataru , Kosugi Kana , Yogo Toshinobu , Hirano Shin-ichi
Published: October 2002

Crack-free La doped K0.4(Pb0.6Ba0.4)0.8Nb2O6 (KPBLN) thin films have been synthesized by
the chemical solution process. Transparent tungsten bronze K0.45(Pb0.6Ba0.4)0.7La0.05Nb2O6
(KPBLN60/5) thin films were fabricated on fused silica substrates at 700°C. KPBLN60/5
thin films on MgO(100) and Pt(100)/MgO(100) also crystallized in the tungsten bronze
single phase with c-axis preferred orientation. Incorporation of La ions in KPBN60 was
found to be effective in forming the tungsten bronze phase and improving the surface
morphology of the synthesized films on the substrates. The propagation modes in the
KPBLN films were observed via the prism coupling method, using a He–Ne (632.8 nm)
laser beam. The Curie temperature (T
c) of the KPBLN60/5 thin film on a
Pt(100)/MgO(100) substrate was around 280°C. The dielectric constant of the KPBLN60/5
film at T
c was about 3000. The KPBLN60/5 thin film on Pt(100)/MgO(100) showed a
spontaneous polarization of 22 µC/cm2, a remanent polarization of 17 µC/cm2 and a
coercive field of 84 kV/cm at -140°C.
Photoluminescence Characteristics of Self-Assembled In0.5Ga0.5As Quantum Dots on Vicinal GaAs Substrates
Authors: Yeh Nien-Tze , Nee Tzer-En , Chang Po-WenShiao , Lee Jen-InnChyi andChing-Ting
Published: October 2002

The properties of self-assembled In0.5Ga0.5As quantum dots on vicinal GaAs substrates are
investigated by atomic force microscopy and temperature-dependent photoluminescence (PL). It is
found that both the size variation and the density of the quantum dots depend closely on the
orientation of substrates. PL spectra indicate that the In0.5Ga0.5As quantum dots on 4°-off substrate
exhibit higher intensity compared to those on 15°-off and exact (100) substrates. The activation
energy derived from the temperature-dependent PL of the In0.5Ga0.5As quantum dots on 4°-off
substrate is higher than that of the dots on 15°-off substrate. The quantum dots on exact (100)
substrate exhibit the lowest activation energy because a thick wetting layer is formed.
Electrical Properties of Microwave-Sintered ZnO Varistors
Authors: Lee Wan-Chui , Liu Kuo-Shung , Lin I-Nan
Published: October 2002

Bi2O3-based ZnO varistor materials were prepared by 2.45 GHz microwave, 24 GHz millimeter-wave or conventional sintering processes. Both millimeter-wave and microwave sintering processes are superior to the conventional sintering process for densifying Bi2O3-based ZnO materials. Moreover, the millimeter-wave sintering process not only densified ZnO materials at a higher rate, but also resulted in significantly better varistor characteristics, as compared with the microwave sintering process. A large nonlinear coefficient and low leakage current density were attained by millimeter-wave sintering the samples under 1100°C for 5 min. A density as high as 95% theoretical density (T.D.) has been achieved, accompanied by a nonlinear coefficient (α) larger than 36, and a leakage current density (JL) smaller than 4.1×10-6A/cm2. The samples had a donor density (Nd) around 2.5× 1024m-3, a surface density (Ns) around 7.23×1011m-2and a potential barrier height (φb) around 2.22 eV. However, the varistor characteristics, including the nonlinear coefficient (α) and leakage current density (JL), degraded markedly for samples sintered at too high a temperature or soaked for too long. This was ascribed to the occurrence of abnormal grain growth, accompanied by the loss of Bi2O3and ZnO species.
Development of Lead Zirconate Titanate Family Thick Films on Various Substrates
Authors: Akiyama Yoshikazu , Yamanaka Kunihiro , Fujisawa Etsuko , Kowata Yasutaro
Published: October 2002

We propose a POS (Piezo on Silicon) actuator, which comprise
piezoelectric materials on a silicon substrate, and the actuation
mechanism uses a bending vibration of a unimorph
structure. Realization of this device was attempted, and the
low-temperature sintering of piezoelectric ceramics, optimization of
the screen-printing method and the barrier layer on a silicon
substrate were developed. Regarding PMN–PZ–PT and PNN–PZ–PT bulk
samples, a sintering temperature of 850°C became possible with
the addition of Li–Bi oxide. Pt–Rh/TaN was used as a barrier layer,
and a 30 µm-thick PNN–PZ–PT film prepared at 900°C on a Si
substrate with a Pt–Rh/TaN buffer layer exhibited ε

r
= 2290, E
c = 8.6 kV/cm and P
r = 5.7 µC/cm2.
Formation of Pb(Zr, Ti)O3–Pb(Zn, Nb)O3 System Piezoelectric Thick Films in Low-Temperature Firing Process
Authors: Kubota Teppei , Tanaka Katsuhiko , Sakabe Yukio
Published: October 2002

Piezoelectric thick-films of 0.7Pb(Zr, Ti)O3–0.3Pb(Zn, Nb)O3 were prepared on ZrO2
ceramic substrates by firing the printed paste at 800–950°C. As a source material for the
paste, glass-ceramics composed of a lead-based glass and nucleation initiators of TiO2 and
ZrO2 were used together with the mother material of Pb(Zr, Ti)O3–Pb(Zn, Nb)O3. The
piezoelectric properties were evaluated with a unimorph actuator formed on the ZrO2 thin
substrate. The remanent polarization was 11 to 12 µC/cm2. The coercive field was 13 to 14 kV/cm and the piezoelectric constant d33 was 260 to 320 pC/N. Thick-film material
consisting of Pb(Zn, Nb)O3 modified PZT powder and glass-ceramics containing nucleation
initiators are very useful for obtaining densification in low-temperature firing and excellent
piezoelectric properties.
Low-Temperature Sintering and Properties of (Pb, Ba, Sr)(Zr, Ti, Sb)O3 Piezoelectric Ceramics Using Sintering Aids
Authors: Hayashi Takashi , Inoue Takayuki , Akiyama Yoshikazu
Published: October 2002

Low-temperature sintering of (Pb0.86Ba0.04Sr0.12)(Zr0.56Ti0.44Sb0.02)O3 (PBSZT) powders was investigated using Pb5Ge3O11 (PGO) or LiBiO2 (LBiO) as sintering aids. 1 wt% PGO or 1 wt% LBiO-added PBSZT powders could be densified into sintered bodies at 800°C for 2 h with a relative density of approximately 96%. The addition of PGO or LBiO significantly improved the sinterability of PBSZT powders, resulting in a reduction of sintering temperature by about 200°C. Dielectric and piezoelectric properties of LBiO-added PBSZT ceramics were superior to those fabricated without sintering aids. However, the addition of PGO was not effective in improving the dielectric and piezoelectric properties. This may be attributable to the microstructural change involving the solid solution reaction between the PBSZT matrix and the PGO additive. The 1 wt% LBiO-added PBSZT bodies sintered at 1000°C exhibited a dielectric constant of 2600, remanent polarization of 14.7 µC/cm2, and longitudinal strain of 0.24%