bluuebunny/crossref_metadata_2025 huggingface dataset:
Paramagnetic Defects in Textured Diamond Films Synthesized by Chemical Vapor Deposition
Authors: Kawaguchi Yuhsuke , Watanabe Ichiro
Published: October 2002

Paramagnetic defects in (100)-textured diamond films are investigated by
electron spin resonance (ESR). The films are deposited on (100) Si substrates using the
bias-enhanced nucleation method. By varying the deposition time, we deposit the films
at various thicknesses ranging from 0.9 µm to 40.4 µm. The density of the
ESR center, known as a complex of carbon-dangling bond and hydrogen, decreases with
increasing film thickness, but even for the thickest film, it is higher than that in
high-quality untextured film by about one order of magnitude. The ESR center is located
not only at the crystal grain boundary but also at the crystal grain. These textured
films are subjected to a large compressive stress and are accompanied with
nondiamond carbons. The high density of the ESR center is considered to be related to a
high amount of vacancy as a consequence of restrained texture growth.
Comparison of Structure and Electron-Field-Emission Behavior of Chemical-Vapor-Deposited Diamond and Pulsed-Laser-Deposited Diamond-Like Carbon Films
Authors: Hsiu-Fung Cheng Hsiu-Fung Cheng , Yi-Chun Chen Yi-Chun Chen , Yin-Ling Wang Yin-Ling Wang , Yuan-Yu Chen Yuan-Yu Chen , Bor-Jau Tsau Bor-Jau Tsau , Tang Chen Tang Chen , I-Nan Lin I-Nan Lin
Published: October 2002

The correlation between the structure and the electron-field-emission behavior of chemical-vapor-deposited (CVD) diamond films and those of pulsed-laser-deposited (PLD) diamond-like carbon (DLC) films is investigated. The CVD films contain crystalline diamonds (sp3-bonds) separated from amorphous carbon (sp2-bonds), possessing a large electron-field-emission current density [(Je)CVD=140 µA/cm2at 21.6 V/µm], a low turn-on field [(E0)CVD=10 V/µm] and a single-value effective work function [(Φe)CVD=0.082 eV]. In contrast, the pulsed-laser-deposited DLC films exhibit even better electron field emission properties [(Je)DLC=320 µA/cm2at 21.6 V/µm, (E0)DLC=8 V/µm] and a wide range of effective work functions [(Φe)DLC=0.016–0.031 eV]. The superior electron-field-emission properties of DLC films, as compared with those of CVD diamonds, are ascribed to their nanostructured grains, which contain a mixture of sp3-bonds and sp2-bonds.
Fabrication and Characterization of the Conic Diamond Field Emission Arrays with Gated Structure
Authors: Chen Chia-Fu , Wang Hung-Chang , Hsieh Hui-Chen
Published: October 2002

In this study, we successfully fabricate conic diamond field emitter array
devices by applying an IC process capable of forming a metal-insulator-semiconductor
(MIS) diode structure. The conic diamonds are selectively
deposited and, ultimately, grow inside of the electric gates. In addition, the field
emission current is measured when applying +1000 V voltage on the anode in
which the applied gate voltage is varied from 0 to 50 volts. Experimental results
indicate that the threshold voltage of this device is about 12 V, and the field
emission current is about 40 µA when the gate voltage is
30 V. Furthermore, current–voltage (I–V) characterization of the electrical properties demonstrates that
the reason for the change of the threshold voltage of conic diamond field emission
arrays (FEAs) fabricated under different CH4 concentration may be
attributed to the diamond tip radius.
Film Growth Modeling of Metal Organic Chemical Vapor Deposition of Copper from Copper(I)-Hexafluoroacetylacetonate Vinyltrimethoxysilane in the Presence of Hydrogen
Authors: Hong Lu Sheng , Jeng Muh Gueng
Published: October 2002

Copper films were deposited by metalorganic chemical vapor
deposition (MOCVD) using copper(I)-hexafluoroacetylacetonate
vinyltrimethoxysilane [Cu(hfac)(VTMOS)] as the precursor in the
presence of H2. In contrast to blanket growth in Ar, selective
growth was maintained on TiN versus SiO2 at a precursor partial
pressure of 1.48×10-2 Torr and 473 K by introducing
H2 as the ambient gas. A film growth modeling based on the
Langmuir-Hinshelwood rate equation was established to describe the
copper deposition at the initial nucleation stage in H2. The
result suggested that H2 physically adsorbed on TiN surface to
hinder the nucleation of copper. Applying a dc bias on substrate
surface showed that the film growth was accelerated by both positive
and negative biases, indicating a disproportionation reaction
dominated the film growth. The less promoted growth rate under
positive bias was attributed to the steric factor between the
intermediate Cu(hfac) and the charged substrate.
Thermochromic Behavior in Poly(p-phenylene vinylene) Derivatives
Authors: Naoki Nakanishi Naoki Nakanishi , Kazuya Tada Kazuya Tada , Mitsuyoshi Onoda Mitsuyoshi Onoda
Published: October 2002

The thermochromic behaviors of poly(2,5-dialkoxy-p-phenylene vinylene)s (ROPPVs) have been studied. The temperature dependence of electrical and optical properties and the variation of properties with the side chain length have been compared with those of poly(3-alkylthiophene)s (PATs). The band-gap energy of ROPPV16 increases gradually from about 2.2 eV at room temperature to about 2.4 eV at 200°C. This temperature dependence of band-gap energy is different from those of PATs, and the difference can be tentatively interpreted in terms of the main chain structure. The photoluminescence intensities of ROPPVs decrease monotonically with increasing temperature. To explain this mechanism, we speculate on the separation of the excited species due to the reduction of distance between polymer main chains and the enhancement of the overlap of π-electrons with the twist of polymer main chains. The ionization potentials of ROPPVs decrease slightly with increasing temperature. However, the origin of this temperature dependence is not clear at this stage.
Modulation-Free Saturated Dispersion Spectroscopy of I2 Using a Common-Path Two-Colour Interferometer with a Nd:YAG Laser
Authors: Hong Feng-Lei , Onae Atsushi , Matsumoto Hirokazu
Published: October 2002

A common-path two-colour interferometer is proposed for the detection of sub-Doppler saturated dispersion resonances of molecular iodine with no modulation on the laser beam. Hyperfine components of the R(56)32-0 line have been observed with a high signal-to-noise ratio by using a Nd:YAG laser. The observed signals of the dispersion resonance, the background of which has a small dependence on the optical geometry, will be used for laser frequency stabilization.
Solid Solution of Epitaxially Grown (Sr, Mg)TiO3 Thin Films
Authors: Suzuki Toshimasa , Nishi Yuji , Fujimoto Masayuki
Published: October 2002

Microstructures of (Sr1-x
Mg
x
)TiO3 thin films
epitaxially grown on (001) SrTiO3 substrates were investigated by
X-ray diffraction and high-resolution transmission electron microscopy
to discuss the solid-solution of the SrTiO3–MgTiO3 system
under pulsed laser deposition processes. In cases of x=0.15 and
x=0.3, magnesium ions were mostly accommodated at A-sites of the
perovskite structure of general formula ABO3, to form
single-phase perovskite thin films without ilmenite secondary phases,
and the possibility of partial B-site occupation of magnesium ions was
inferred to interpret the formation of (100) and (010) planar defects
with a crystallographic shear structure. The
(Sr0.5Mg0.5)TiO3 thin film exhibits a phase-separated
microstructure consisting of an epitaxial crystalline perovskite phase
and an amorphous phase, which could be derived from the limitation of
the magnesium solubility in the SrTiO3 perovskite lattice.
A Soft-X-Ray Imaging Microscope with a Multilayer-Coated Schwarzschild Objective: Imaging Tests
Authors: Toyoda Mitsunori , Shitani Yoshitaka , Yanagihara Mihiro , Ejima Takeo , Yamamoto Masaki , Watanabe Makoto
Published: October 2002

We constructed a soft-X-ray imaging microscope based on a multilayer-coated
Schwarzschild objective. It provides an element-sensitive image in terms of the
characteristic soft X-rays selectively reflected by the multilayer coating. The
Schwarzschild objective was designed to have a 50× magnification and a
numerical aperture of 0.25. The mirrors of the objective were coated with Mo/Si
multilayers to reflect the Si L emission. The overall throughput of the objective was
14% at a peak wavelength of 13.3 nm. The 5-µm-wide stripe of lithographically
patterned SiO2 was observed under irradiation with an electron beam of
1 µA accelerated to 2.5 kV.
Hollow Beam Electron Gun for Electron Beam Reducing Image Projection System: Computer Simulation
Authors: Nakasuji Mamoru , Shimizu Hiroyasu
Published: October 2002

A new hollow beam electron gun with an annular emission area is described. A
cathode image is focused at the contrast aperture of the projection lens system, and
the mask is irradiated by a uniform intensity electron beam which is conjugate to a
flattop region near the crossover. The emittance is 7.8 mm mrad for a beam energy of
100 keV. Brightness can be varied from 8×102 to
4.5×103 A/cm2sr by changing only the cathode temperature. The gun
crossover, the flattop area and the cathode image axial positions can also be varied
widely, without changing gun brightness and emittance, by changing the gun control
anode potential. The emission current can be reduced by reducing the “ratio
(emission area radial width/maximum emission area radius) of the cathode surface”
without changing the emittance and with little brightness change. Using this simulated
electron gun, the basic electron optics of an electron beam projection lithography
system with a hollow beam is designed.
Selective Emission of Al2O3/Er3Al5O12 Eutectic Composite for Thermophotovoltaic Generation of Electricity
Authors: Hitoshi Sai Hitoshi Sai , Hiroo Yugami Hiroo Yugami , Kazuya Nakamura Kazuya Nakamura , Narihito Nakagawa Narihito Nakagawa , Hideki Ohtsubo Hideki Ohtsubo , Shigenao Maruyama Shigenao Maruyama
Published: October 2002

The emissive properties of Al2O3/Er3Al5O12 eutectic composite were measured in the temperature range of 1000 to 1700 K. It was confirmed that the Al2O3/Er3Al5O12 eutectic composite has selective emission bands at a wavelength of 1.5 µm attributable to Er3+ ions. It is found that the intensity obeys the T
4-law. The emittance of over 0.8 is observed in the selective region. Since these emission bands match up the sensitive region of the GaSb PV cell spectrally, the Al2O3/Er3Al5O12 eutectic composite is a suitable emitter material for using in thermophotovoltaic generation systems. The effects of temperature and thickness on the selective emission efficiency have been studied and discussed.
Temperature Dependence of Optical Properties of h-GaN Films Studied by Reflectivity and Ellipsometry
Authors: Siozade Laure , Colard Stéphane , Mihailovic Martine , Leymarie Joël , Vasson Aimé , Grandjean Nicolas , Leroux Mathieu , Massies Jean
Published: October 2002

Spectroscopic ellipsometry (SE) carried out at 300 K together with reflectivity measurements
performed from 5 to 300 K are used to determine the temperature dependence of the refractive index
of hexagonal GaN films between 360 and 600 nm. The refractive index is well described with a Sellmeier
dispersion law and its variation with temperature is given. Below the band gap, the three excitonic
features (labelled A, B and C) appearing in the reflectivity spectra are analysed within a multi-polariton
model which includes the spatial dispersion. The transition energy, broadening parameter and oscillator
strength are derived. The temperature dependence of A and B broadening parameters is analysed.
Mechanism of Layer-by-Layer Oxidation of Si(001) Surfaces by Two-Dimensional Oxide-Island Nucleation at SiO2/Si Interfaces
Authors: Watanabe Heiji , Baba Toshio , Ichikawa Masakazu
Published: October 2002

We have studied the mechanism of layer-by-layer oxidation of Si(001)
surfaces. The layer-by-layer oxidation was confirmed and precisely monitored by
scanning reflection electron microscopy (SREM). By combining SREM and scanning
tunneling microscopy (STM) methods, we investigated the change in
atomic-scale roughness at SiO2/Si(001) interfaces during the
oxidation. We found that, while the oxide interface is atomically flat
after the oxidation of each layer is complete, nanometer-scale oxide
islands with a single atomic height are densely nucleated at the
interface during the oxidation of each layer. We also observed an
oscillation in the intensity of reflection high-energy electron
diffraction (RHEED) spots during the top-layer oxidation. These
results clearly indicate that the layer-by-layer oxidation proceeds by
the nucleation of nanometer-scale oxide islands at the interfaces and
by their preferential lateral island growth.
Effects of Hydrogen and Deuterium Annealing on Plasma Process Induced Damages
Authors: Chang-Geun Ahn Chang-Geun Ahn , Jun-Hyung Kim Jun-Hyung Kim , Young-Kwang Kim Young-Kwang Kim , Yong-Hee Lee Yong-Hee Lee , Bongkoo Kang Bongkoo Kang
Published: October 2002

For n-channel metal-oxide semiconductor field effect transistor(MOSFET) devices with thin
gate oxide, the effects of low temperature hydrogen and deuterium
annealing on plasma process-induced damages are examined. The test
devices were first exposed to the plasma during poly-Si gate or
metal processes, and then the device characteristics were measured
with the charge pumping method. It was observed that the metal
process induced more interface traps than the poly-Si gate
process. D2 annealing was more effective in curing the
interface damages than H2 annealing, and the strength to
resist ac electrical stress was enhanced significantly after
D2 annealing. The stability of interface properties was
increased with the annealing temperature and time. It is concluded
that the latent damages, which appear after electrical stress,
originate from the plasma process-induced damages that were
unintentionally passivated by hydrogen atoms during subsequent
processes.
Optical Characterization of Gate Oxide Charging Damage by Photoreflectance Spectroscopy
Authors: Masashi Agata Masashi Agata , Hideo Wada Hideo Wada , Osamu Maida Osamu Maida , Koji Eriguchi Koji Eriguchi , Akira Fujimoto Akira Fujimoto , Takeshi Kanashima Takeshi Kanashima , Masanori Okuyama Masanori Okuyama
Published: October 2002

Thin gate oxide charging damage induced by plasma exposure in the
metal-oxide-semiconductor (MOS) structure has been studied by
photoreflectance (PR) spectroscopy. The PR signal intensity around the photon
energy of 3.4 eV is found to decrease as the plasma exposure time increases.
The capacitance–voltage (C–V) characteristic shows the generation of
SiO2/Si interface states as well as that of electron trap sites in
the oxides induced by the DC mode Ar plasma exposure. The SiO2/Si
interface state plays the role of a recombination center for the photo
generated carriers, resulting in the decrease in the surface potential
change. On the
other hand, the electron trapped in the oxide increases the surface potential.
Therefore, the decrement in the PR signal intensity is considered to
correspond primarily to the SiO2/Si interface state generation induced
by the plasma-process, because the signal intensity decreases with the
decrease of the surface potential.
Electrical Properties of Crystalline Ta2O5 with Ru Electrode
Authors: Kim Jin-Won , Nam Sang-Don , Lee Seung-Hwan , Won Seok-Jun , Kim Wan-Don , Yoo Cha-Young , Park Young-Wook , Lee Sang-In , Lee Moon-Yong
Published: October 2002

As one candidate capacitor for dynamic random access memories
(DRAMs) of 4 Gbit and beyond, we investigated the electrical
properties of Ru/Ta2O5/Ru. In this paper, the dielectric
constant of Ta2O5 was measured as a function of annealing
temperature and, also, its dependence on film thickness was
studied. The effect of postannealing, which was performed after
forming a capacitor, on the leakage current of
Ru/crystalline-Ta2O5/Ru capacitor was
evaluated. Additionally, the leakage current was investigated as a
function of Ta2O5 film thickness. Through these
experiments, a reliable 7 Å Toxeq. of Ta2O5 with a Ru
electrode was obtained, which indicates that the
Ru/crystalline-Ta2O5/Ru capacitor is a promising candidate
for DRAMs of 4 Gbit and beyond.
Characteristics of 0.25 µm Ferroelectric Nonvolatile Memory with a Pb(Zr, Ti)O3 Capacitor on a Metal/Via-Stacked Plug
Authors: Amanuma Kazushi , Kobayashi Sota , Tatsumi Toru , Maejima Yukihiko , Hada Hiromitsu , Yamada Junichi , Miwa Tohru , Koike Hiroki , Toyoshima Hideo , Kunio Takemitsu
Published: October 2002

A 0.25-µm ferroelectric memory with 16 kbit-cell array was
fabricated. A Pb(Zr, Ti)O3 (PZT) capacitor was formed on a
metal(Al)/via(W)-stacked plug using low temperature metal organic
chemical vapor deposition (MO-CVD). The backend process had no
effect on the PZT capacitor properties. The 1×1 µm2
capacitor shows good fatigue and imprint
endurance. Signal voltage on the bit-line in the cell array is
1.06 V for switching and 0.58 V for unswitching. These results
agree well with the pulse-response measurement of the parallel
capacitor. However, the signal voltage deviation becomes larger with
the capacitor size reduction. The 16 kbit-cell array shows the
column access time of 50 ns and the minimum operation voltage of
1.6 V.
Impact of Nitrogen Profile in Gate Oxynitride on Complementary Metal Oxide Semiconductor Characteristics
Authors: Tamura Yasuyuki , Shigeno Mayumi , Ohkubo Satoshi , Irino Kiyoshi , Nakanishi Toshiro , Takasaki Kanetake
Published: October 2002

We demonstrated that the control of the nitrogen profile in the gate oxynitride
for complementary metal oxide semiconductors (CMOSs) is very important. We grew NO
or N2O nitrided gate oxide at 800°C or 900°C to prepare three kinds of
oxynitrides with different nitrogen profiles, and investigated the atomic configuration
and the chemical state of nitrogen using secondary ion mass spectroscopy and X-ray
photoelectron spectroscopy. Furthermore, we fabricated CMOS field effect transistors
with gate oxide and oxynitride, and evaluated the interface state density and the hot
carrier immunity. By systematical investigation of the relationship between the
nitrogen profile and the electrical characteristics, we found that the nitrogen in the
oxynitride should exist only at the interface for realizing the CMOS devices having high
performance and high reliability.
Device Performance Improvement Based on Transient Enhanced Diffusion Suppression in the Deep Sub-Quarter Micron Scale
Authors: Hyun-Sik Kim Hyun-Sik Kim , Jong-Hyon Ahn Jong-Hyon Ahn , Duk-Min Lee Duk-Min Lee , Kwang-Dong Yoo Kwang-Dong Yoo , Soo-Cheol Lee Soo-Cheol Lee , Kwang-Pyuk Suh Kwang-Pyuk Suh
Published: October 2002

In the deep sub-quarter micron scale, the transient enhanced
diffusion (TED) of the gate channel region gives rise to the
variation of device characteristics due to the influence of
interstitial silicon atoms generated by the extension ion
implantation damage. The channel impurity variation caused by TED
becomes a dominant factor and brings about a more severe fluctuation
of the threshold voltage (V
th) than the physical gate
channel length (L
gate) or the gate-oxide
(G
ox) thickness variation does. This work presents the
results of suppressing the reverse short channel effect (RSCE) which
is shown due to TED by using the local channel implantation
process. In the case of using a boron source as an n-type channel
(n-channel) dopant, the 10% improvement of the RSCE and the 70%
reduction of the V
th fluctuation are achieved through
TED suppression by rapid thermal anneal (RTA)
treatment. Furthermore, we not only demonstrates the 15% increase
of the current driving capability but also clearly removes the RSCE
by realizing the super-steep retrograded (SSR) channel doping
profile with an indium species as the n-channel dopant and adopting
RTA process.
Investigation of Reliability Degradation of Ultra-Thin Gate Oxides Irradiated under Electron-Beam Lithography Conditions
Authors: Chong Pei Fen , Cho Byung Jin , Chor Eng Fong , Joo Moon Sig , Yeo In Seok
Published: October 2002

The effect of Electron-beam irradiation on the reliability of ultra-thin gate oxide has
been studied under typical Electron-beam lithography conditions. A large increase of
low-field excess leakage current was observed on irradiated oxides, which was found
to be very similar to the electrical stress-induced leakage currents. An experimental
relationship between the total Electron-beam dosage and the equivalent charge
fluence, which induces the same amount of current degradation, has been established
for different oxide thickness. This allows for easier prediction of radiation damage. It
has also been found that Electron-beam irradiation generates much larger amount of
oxide bulk traps but generates a comparable amount of interface states, compared to
electrical stress. Quasi-breakdown characteristics show that Electron-beam irradiation
up to a dose of 500 µC/cm2 does not accelerate
quasi-breakdown of ultra-thin gate oxide.
Direct Measurement of Transient Drain Currents in Partially-Depleted SOI N-Channel MOSFETs Using a Nuclear Microprobe for Highly Reliable Device Designs
Authors: Iwamatsu Toshiaki , Nakayama Kouichi , Takaoka Hiromichi , Takai Mikio , Yamaguchi Yasuo , Maegawa Shigeto , Inuishi Masahide , Kinomura Atsushi , Horino Yuji , Nishimura Tadashi
Published: October 2002

Transient drain currents caused by proton microprobe
irradiations in partially-depleted (PD) silicon-on-insulator (SOI)
metal-oxide-semiconductor field-effect transistors (MOSFETs) were
analyzed for soft-error issues. Transient currents of the body-tied
MOSFETs can be lowered compared to those of the floating body SOI
MOSFETs by suppression of the floating body effect. The
effectiveness of the body-tie structure was analyzed by device
simulation. Increase in the body potential by proton irradiation is
suppressed efficiently in the narrow-channel body-tied SOI MOSFETs
due to the low body resistance to excess carrier extraction. On the
other hand, the body potential of narrow-channel floating body SOI
MOSFETs increase to higher levels than those of the wide-channel
MOSFETs due to the lower body capacitance. It is indicated that
narrow-channel body-tied SOI MOSFETs are suitable for highly
reliable devices. Moreover, a more reliable body-tied structure with
high impurity concentration in the body regions to reduce the body
resistance in the structure is proposed. The collected drain charge
was able to be reduced by utilizing this structure. These devices
are expected to be applied to highly reliable LSI's used for
satellite systems, server and mainstream LSI applications of the
multimedia era.
New SOI Complementary-Bipolar Complementary-MOS (CBiCMOS) with Merged Device Structure
Authors: Zheng Yue-Sheng , Asano Tanemasa
Published: October 2002

A complementary-bipolar complementary-metal-oxide-semiconductor
(CBiCMOS) inverter has been
developed using bipolar/metal-oxide-semiconductor (MOS) merged
transistors on a silicon-on-insulator (SOI) structure. The pull-up and
pull-down functions are driven by p-channel-MOS/npn and
n-channel-MOS/pnp merged transistors, respectively. The merged
transistor consists of a bipolar structure built in to the drain
regions of each MOS field-effect-transistor (MOSFET) of the
complementary MOS (CMOS) device, which amplifies the channel
current. The device has been fabricated using a reverse bond-and-lap
technique to form a fully isolated silicon on insulator. The
amplification of the MOSFET current by the built-in bipolar
transistor is experimentally verified. Logic operation of the inverter
is demonstrated. The dependence of the propagation delay time on the
load capacitance connected to inverters indicates that the new
SOI-CBiCMOS has a much larger driving ability than conventional CMOS.
A Wide-Bandwidth-Output Direct Digital Synthesizer with Multiple Delay Generators
Authors: Nosaka Hideyuki , Yamaguchi Yo , Muraguchi Masahiro
Published: October 2002

A new type of phase interpolation direct digital synthesizer (DDS) that can
generate signals up to the clock frequency is proposed. The maximum output frequencies
of conventional DDSs are limited to half the clock frequencies. To eliminate this
frequency limit, we designed a new ROM-less DDS with multiple delay generators that
are mutually triggered by a pulse distributor. Pulse distribution plays an important role
in reducing the effective resetting time of the delay generators. We derived a
theoretical expression which gives the maximum output frequency of the new DDS.
According to the expression, the maximum output frequency can be determined by the
number of delay generators and maximum leaking time. We also show that the new DDS
can produce output signals up to the clock frequency with three or four delay
generators. Experimental results confirm frequency synthesizer operation in which the
spurious level is reduced by the delay generators. The results also confirm that the
maximum output frequency is not limited to half the clock frequency when using two
delay generators. This is consistent with the theoretical expression.
Thermal Properties of 1.3 µm AlGaInAs Multi Quantum Well Ridge Waveguide Lasers
Authors: Kubota Munechika , Hamano Kayo , Takemasa Keizo , Kobayashi Masao , Wada Hiroshi , Munakata Tsutomu
Published: October 2002

We have fabricated 1.3 µm AlGaInAs/InP multi-quantum-well
(MQW) ridge waveguide lasers with both junction-up and junction-down
mounting, and compared the thermal resistance (R
th) and
other laser characteristics such as the maximum CW operating temperature
(T
max), characteristic temperature of threshold current
(T
0), and the maximum CW output power (P
max).
The thermal resistance was found to be 73.6 K/W and 43.5 K/W for
junction-up and -down mounting, respectively. T
0, T
max
and P
max were also improved by 7 K, 20°C and 20%
in the junction-down configuration, respectively, which is due to a
reduction of the thermal resistance. A CW T
max as high as
185°C has also been achieved with 350-µm-long high-reflective-coated
lasers, which is one of the highest CW operation temperature reported
to date for InP-based long wavelength lasers.
Experimental and Simulated Results of Room Temperature Single Electron Transistor Formed by Atomic Force Microscopy Nano-Oxidation Process
Authors: Gotoh Yoshitaka , Matsumoto Kazuhiko , Bubanja Vladimir , Vazquez Francisco , Maeda Tatsuro , Harris James S.
Published: October 2002

A planar-type single electron transistor (SET) was fabricated by the atomic force
microscopy (AFM) nano-oxidation process. The fabricated SET showed the Coulomb
oscillation characteristic with the period of about 2 V at room temperature. From the
three-dimensional simulation, it is found out that the smaller the SET island size, the
smaller the tunnel junction capacitance, and the tunnel junction capacitance shows a
weak dependence on the tunnel junction width. Using the analytical model, the reason
for this weak dependence was clarified.
Wafer-Bonded AlGaInP/Au/AuBe/SiO2/Si Light-Emitting Diodes
Authors: Horng Ray-Hua , Wuu Dong-Sing , Wei Sun-Chin , Tseng Chung-Yang , Huang Man-Fang , Chang Kuo-Hsiung , Liu Pin-Hui , Lin Kun-Chuan
Published: October 2002

An AlGaInP light-emitting diode (LED) with a Au/AuBe/SiO2/Si mirror substrate
has been successfully fabricated by the wafer bonding technique. The mirror-substrate
LED is capable of emitting luminous intensity of 90 mcd under 20 mA injection. It is
clearly far superior to the conventional absorbed-substrate LED with a distributed Bragg
reflector structure (≤1 mcd). This device exhibits normal p-n diode behavior with a
forward voltage of less than 2 V operating at 20 mA. The leakage current is about 3 nA
under a 36 V reverse bias. This result indicates that the wafer bonding technique does not adversely affect the I–V characteristic of the LED device. Moreover, the emission
wavelength of the bonded LED was independent of the injection current. The low forward
series resistance and the Si substrate providing a good heat sink solve the joule heating
problem inherent in conventional LEDs.
Edge-Illuminated Refracting-Facet Photodiode with Large Bandwidth and High Output Voltage
Authors: Fukano Hideki , Muramoto Yoshifumi , Matsuoka Yutaka
Published: October 2002

A high-speed and high-output-voltage edge-illuminated refracting-facet
photodiode (RFPD) has been developed by employing a thin absorption layer. In the RFPD,
the incident light parallel to the up-side surface is refracted at an inwardly angled
facet and penetrates at a small angle in the absorption layer. The absorption length is
thus effectively longer, resulting in high responsivity even at a thin absorption layer. In
addition, since this RFPD uses a p-metal as a reflector, the absorption length is
doubled. The light penetration at a small angle in the absorption layer also reduces the
carrier density, and thinning the absorption layer effectively suppresses the influence
of field modulation due to space charges. The fabricated RFPD has a responsivity as high
as 0.69 A/W for 1.55 µm light even with an absorption layer as thin as
0.43 µm, a maximum 3 dB bandwidth of 66 GHz, and a high output peak voltage
of over 2.5 V.
The Effect of Isoelectronic In-Doping on the Structural and Optical Properties of (Al)GaN Grown by Metalorganic Vapor Phase Epitaxy
Authors: Shigeo Yamaguchi Shigeo Yamaguchi , Michihiko Kariya Michihiko Kariya , Shugo Nitta Shugo Nitta , Hiroshi Amano Hiroshi Amano , Isamu Akasaki Isamu Akasaki
Published: October 2002

We have studied the effect of isoelectronic In-doping on the structural and optical properties of GaN and Al0.05Ga0.95N. The films were grown by atmospheric metalorganic vapor phase epitaxy at 950°C in H2 or N2 carrier gas (hereafter referred to as H2-(Al)GaN and N2-(Al)GaN, respectively) with a low-temperature deposited AlN buffer layer. With the technique, we were able to control the strain in the films. Indeed, with increasing trimethylindium flow, the strain in GaN decreased, and accordingly, the tilting and twisting components of the crystalline mosaicity were also decreased. The photoluminescence (PL) emission peak energy shifted in accordance with the strain in GaN. Strong enhancement of the excitonic PL intensity of In-doped GaN and AlGaN was observed. In all the samples, room temperature PL mapping for linewidth and peak wavelength showed that with the addition of In, the uniformity of the PL improved significantly.
Electrical Properties of Amorphous Rh Oxide Thin Films Prepared by Reactive Sputtering
Authors: Yoshio Abe Yoshio Abe , Kiyohiko Kato Kiyohiko Kato , Midori Kawamura Midori Kawamura , Katsutaka Sasaki Katsutaka Sasaki
Published: October 2002

Conducting Rh oxide thin films were prepared by sputtering a Rh target in an Ar and O2 mixed gas. Effects of the oxygen gas flow ratio on the crystallinity, chemical bonding state and resistivity were studied. Amorphous Rh2O3 films were prepared at an O2 flow ratio of 20%. The Rh2O3 films had a relatively high resistivity of 2 mΩcm and a negative temperature coefficient of resistance (TCR) of -1000 ppm/°C, which indicated semiconducting characteristics. On the other hand, amorphous RhOx films with a composition of 1.5 ≤x ≤1.7 were prepared at O2 flow ratios above 40%. Resistivity of these RhOx films were 800 µΩcm and had almost no temperature dependence. Metallic conduction characteristics of RhO2 were assumed to be revealed by the decrease in the oxygen deficiency.
Fine Structures of Fe-Related Deep Levels in GaAsP
Authors: Kang Junyong , Zhan Huahan , Huang Qisheng
Published: October 2002

The capacitance transients caused by hole emissions from
Fe-related deep levels were measured in GaAs and GaAs0.77P0.23 at
different temperatures. Non-exponential transients were investigated
under different conditions and found to relate to the alloy random
effect. The transients were decomposed using a Laplace defect
spectroscope (LDS). The three well-resolved sharp peaks in the LDS
spectra of GaAs0.77P0.23 were assigned to the fine
structures of the
Fe-related deep levels. The activation energy differences of the
fine structures were determined by linear fitting of the slopes of
temperature dependences of hole emission rates. The results suggest
that the local composition fluctuation in the nearest neighbors of
Fe atoms is likely to be responsible for the fine structures.
Measurement of Dynamic Strain during Ultrasonic Au Bump Formation on Si Chip
Authors: Hizukuri Masafumi , Tanemasa Asano Tanemasa Asano
Published: October 2002

The strain generated at the surface of a Si chip during the ultrasonic formation of a Au bump was dynamically measured using strain gauges fabricated on the chip. The piezoresistive-type strain gauge was designed to be sensitive to unidirectional strain at the surface. Measured results show that the magnitude and direction of strain strongly depend on the relative position to the Au bump and bonding sequence. It has been found that the maximum strain is generated near the periphery of the bump during the application of ultrasonic vibration, while the maximum residual strain appears near the center of the bump. Analysis with the finite element method (FEM) has shown a good qualitative agreement with the measured results. Effects of direct bump formation on MOS devices were examined by time dependent dielectric breakdown (TDDB) tests and measurement of flat band voltage of metal oxide semiconductor (MOS) capacitors. The reliability of MOS gate oxide was found to decrease due to both ultrasonic and residual strain.
Passivation of SiO2/Si Interfaces Using High-Pressure-H2O-Vapor Heating
Authors: Keiji Sakamoto Keiji Sakamoto , Toshiyuki Sameshima Toshiyuki Sameshima
Published: October 2002

High-pressure H2O vapor heating was used for the passivation of silicon surface. The thermally evaporated SiO
x
films formed on the silicon surface was oxidized and Si–O bonding density increased with an activation energy of 0.035 eV with increasing heating temperature upon heat treatment with 1.0 ×106 Pa H2O vapor. The peak wave number and full width at half maximum of the Si–O absorption band due to the Si–O–Si antisymmetric stretching vibration mode were changed to 1077 cm-1 and 72 cm-1, respectively. The density of silicon dangling bonds was reduced from 2.0 ×1017(as deposited) to 1.4 ×1015 cm-3 by heat treatment. The effective surface recombination velocity of the p-type silicon wafer that was coated with SiO
x
films was markedly reduced from 405 cm/s (as deposited) to 13 cm/s by heat treatment with 2.1 ×106 Pa-H2O vapor at 260°C for 3 h. The interfaces retained the low recombination velocity 8000 h after keeping the sample in air. Effective field effect passivation was demonstrated using a SiO
x
/SiO2 double layered structure formed by the combination of thermal evaporation and heat treatment with high-pressure H2O vapor.
AlGaAs/InGaAs Pseudomorphic Doped Channel Field Effect Transistor with A P-AlAs Buffer Layer Grown by Metalorganic Chemical Vapor Deposition
Authors: Choi Seung June , Chung Youn Kyu , Kim Dae Hyun , Chu Hyung Joon , Seo Kwang Seok
Published: October 2002

An AlAs buffer layer was successfully utilized in a
0.25-µm-gate pseudomorphic doped channel field effect transistor
for the first time by growing a high quality p-AlAs layer by
metalorganic chemical vapor deposition that attenuated the commonly
observed roughness-induced degradation. Compared with a device
containing a thick GaAs buffer layer alone, the RF
g
m/g
DS ratio and f
max in this
device were increased by 42% to 39 and by 19% to 160 GHz,
respectively, at the expense of a slight decrease in g
m
and f
T. As a result of the reduced leakage conduction
through the buffer layer at high temperatures, the fabricated doped
channel FET with the p-AlAs buffer layer was completely pinched off
and it exhibited excellent DC current–voltage characteristics even
at elevated temperatures up to 200°C.
PdGe-Based Ohmic Contact on n-GaAs with Highly and Poorly Doped Layers
Authors: Lim Jong-Won , Mun Jae-Kyoung , An Sung-Jong , Nam Sungun , Kwak Myeong-Hyeon , Kim Haecheon , Lee Jae-Jin
Published: October 2002

We report the ohmic contact formation mechanism for a low
contact resistance PdGe-based system on a GaAs sample containing
highly and poorly doped layers annealed in the temperature range of
380–450°C. The lowest average specific contact resistance of
the Pd/Ge/Ti/Pt ohmic contact was 2.4×10-6 Ω·cm2 after annealing at
400°C. This was believed to be due to the formation of a
Ga5Pd compound. Cross-sectional scanning electron microscopy
and Auger electron spectroscopy were utilized in this study. The
contact was thermally stable after isothermal annealing at
400°C for 6 h.
Simulation of Dopant Redistribution During Gate Oxidation Including Transient-Enhanced Diffusion Caused by Implantation Damage
Authors: Tetsuya Uchida Tetsuya Uchida , Katsumi Eikyu Katsumi Eikyu , Eiji Tsukuda Eiji Tsukuda , Masato Fujinaga Masato Fujinaga , Akinobu Teramoto Akinobu Teramoto , Tomohiro Yamashita Tomohiro Yamashita , Tatsuya Kunikiyo Tatsuya Kunikiyo , Kiyoshi Ishikawa Kiyoshi Ishikawa , Norihiko Kotani Norihiko Kotani , Satoru Kawazu Satoru Kawazu , Chihiro Hamaguchi Chihiro Hamaguchi , Tadashi Nishimura Tadashi Nishimura
Published: October 2002

Dopant redistribution during gate oxidation in metal-oxide-semiconductor (MOS) fabrication processes has been studied by secondary-ion mass spectrometry (SIMS). In the first set of experiments, dopant profiles after gate oxidation are measured and compared to those after N2 annealing. From the measured profiles, the contribution of oxidation-enhanced diffusion (OED) to the entire dopant redistribution is determined and an OED model parameter is calibrated. In the second set of experiments, samples which are subjected only to wafer loading and unloading steps are prepared and dopant profiles are measured. From the measured profiles, the magnitude of transient-enhanced diffusion (TED) which occurs during the wafer loading step is estimated and an interstitial-clustering parameter is calibrated. The parameters calibrated in this study are combined with the point-defect parameters taken from the literature, and dopant redistribution during the entire gate oxidation cycle is simulated. Calculated dopant profiles agree well with the measured SIMS profiles and show correct time dependence of TED and OED, as observed in the present experiments. In the simulations, interstitial concentration at the oxidizing Si/SiO2 interface is found to be 40 times the equilibrium concentration. The supersaturation caused by surface oxidation is small and the contribution of OED is negligible under typical gate oxidation conditions where oxide thickness is less than 100 Å. Dopant profiles after gate oxidation are mainly dominated by TED. However, as oxidation proceeds, the contribution of OED increases because it continues while TED almost ends in the wafer loading step of gate oxidation. Segregation of boron in the channel region is also studied. It is found that a greater amount of boron is lost in oxidation than in N2 annealing. The effect of segregation on device characteristics is not negligible for buried-channel PMOS devices, because the threshold voltage of the devices is sensitive to the change in the amount of boron.
Ga0.5In0.5P Barrier Layer for Wet Oxidation of AlAs
Authors: Lee Shih-Chang , Lee Wei-I
Published: October 2002

We study the stability of Ga0.5In0.5P and
Al0.4Ga0.6As barrier layers for wet thermal oxidation of
AlAs on GaAs. Samples with a Ga0.5In0.5P or
Al0.4Ga0.6As barrier layer are oxidized in a water vapor
environment under various oxidation conditions. The results of
photoluminescence and secondary-ion mass spectrometry (SIMS) depth
profile measurements indicate that the Ga0.5In0.5P barrier
layer is more stable than the Al0.4Ga0.6As layer at higher
oxidation temperatures and longer periods of oxidation time.
Characterization of Interface in GaAs Epitaxial Wafer by Spatially Resolved Photoluminescence from Cleaved Face
Authors: Masaki Noji Masaki Noji , Makoto Kiyama Makoto Kiyama , Michio Tajima Michio Tajima
Published: October 2002

We characterized the interface between the epitaxial layer and substrate of a GaAs wafer by measuring the microscopic photoluminescence (PL) on the cleaved face of the wafer. The intensity of the band-edge PL was higher in the epitaxial layer than in the substrate and locally decreased at the interface. This finding indicates that the non-radiative recombination centers are accumulated at the interface.
Two-Dimensional Photonic Crystal Waveguides with 60° Bends in a Thin Slab Structure
Authors: Naoyuki Fukaya Naoyuki Fukaya , Daisuke Ohsaki Daisuke Ohsaki , Toshihiko Baba Toshihiko Baba
Published: October 2002

We experimentally investigated the light propagation characteristics of two-dimensional photonic crystal waveguides, for the first time. The difficulty of fabricating photonic crystals with airholes was reduced by employing a thin slab structure with a GaInAsP high refractive index core, and by employing air and SiO2low index claddings. The light propagation through channels composed of a series of defects in the photonic crystal was observed in the wavelength range 1.51–1.55 µm. Smooth propagation was maintained even beyond 60° channel bends. The wavelength and polarization dependence of propagation characteristics as well as the peculiar scattering of light to space were explained by the photonic band theory.
Brightness and Contrast Enhancement of Reflective Liquid Crystal Displays by Microlens Array Light Control Film
Authors: Ko Fu-Jen , Shieh Han-Ping David
Published: October 2002

An off-axis microlens array light control film (OMA-LCF) for
brightness and contrast enhancement in reflective liquid-crystal
displays (LCDs) is demonstrated. The OMA-LCF is constructed with an
off-axis microlens array (with a half-lens body) and then laminated
to the top surface (toward the viewer) of the uppper glass of the
reflective LCDs. The filmlike device directs incident light to a
reflected cone with a controlled angular profile nearly normal to
the display surface, yields a gain of about 1× to 10×
of MgO standard-white in the typical viewing region from 0°
to 20°. Moreover, glare and optical losses can be greatly
reduced.
Dielectric Properties of Internal Capacitors in Co-fired Ceramic Substrates
Authors: Chen Lih-Shan , Fu Shen-Li , Lin Wen-Kuan , Huang Kwan-Dar
Published: October 2002

Dielectric properties of barium titanate-based internal
capacitors characterized by capacitance, dissipation factor, and
temperature change in capacitance are reported. A capacitance of
about 10 nF/cm2 with the dissipation factor of 2.3% is obtained for
the BaTi0.975O3+2 wt% LiF
internal capacitor after being co-fired with low dielectric constant
ceramic substrates at 900°C. The percent change of capacitance
is confined within ±10%. The dissipation factor is stable and
decreases with increasing temperature.
Residual Stress Analysis of Pt Bottom Electrodes on ZrO2/SiO2/Si and SiO2/Si Substrates for Pb(ZrTi)O3 Thick Films
Authors: Jeon Yongbae , Kim Dong Goo , No Kwangsoo , Kim Seong-Jin , Chung Jaewoo
Published: October 2002

We fabricated Pt bottom electrodes on SiO2/Si and
ZrO2/SiO2/Si substrates by DC magnetron sputtering. The
residual stress of the Pt layers deposited on SiO2 and
ZrO2/SiO2 diffusion barrier layers was measured by an
X-ray diffractometer (XRD). The Pt layers deposited at 400°C
exhibited tensile residual stress, but the Pt layers deposited at
room temperature exhibited compressive residual stress. Lead
zirconate titanate (PZT) thick films were fabricated on the Pt
electrodes by a screen printing method. The dielectric permittivity,
tan
δ, P–E hysteresis loop, breakdown field, coercive
field and piezoelectric constant were measured for the PZT thick
films. A PZT thick film on Pt/ZrO2/SiO2/Si displaying a
low tensile residual stress exhibited the remanent polarization,
coercive field, dielectric permittivity (ε
r),
dissipation factor (tan
δ), breakdown field and piezoelectric
constant (d
33) of 13 µC/cm2, 8.5 kV/cm, 800, 0.015,
12 MV/m and 343 µC/N, respectively.
The Equivalent Circuit of an AT-Cut Quartz Resonator and Its Application
Authors: Chen Ping-Cheng , Wu Long
Published: October 2002

The equivalent circuit of a AT-cut quartz resonator can be
modified as a series circuit consisting of an inductance, a
capacitance, a resistance in parallel with a capacitor, which are
related to the dimensions, density, and elastic, dielectric,
piezoelectric constants and electrode area of the quartz. In the
other hand, a contacting fluid will cause an extra resistance and an
inductance appeared, and an inductance appeared due to electrode
mass loading effect. In this paper, two derivation methods of
equivalent circuit models are used and compared to explain an AT-cut
quartz resonator. Also a method to distinguish and calculate each
components in equivalent circuit from gain-phase measurement is
provided. Finally, the relation between air pressure and equivalent
inductance and resistance are measured. The results shown that the
lower air pressure the smaller equivalent inductance and resistance,
when air pressure change from 1atm to 1 g/cm2, the equivalent
resistance and the resonant frequency of resonator will change
5 Ω and 90 Hz, respectively.
Thermo-reversible Liquid-Crystal Gels: Towards a New Processing Route for Twisted Nematic Displays
Authors: Janssen Rob H. C. , Stümpflen Volker , Bastiaansen Cees W. M. , Broer Dirk J. , Tervoort Theo A. , Smith Paul
Published: October 2002

Thermo-reversible gels of the liquid-crystal system LC-TL213 with 12-hydroxyoctadecanoic acid (HOA) were cast in a twisted nematic (TN) configuration that is switchable by AC electric fields. Critical in this process was to choose a processing temperature higher than the sol–gel temperature but lower than the nematic-isotropic transition of the system. The latter condition originates in the phase diagram of the system which displays a monotectic-type point at which a liquid is in equilibrium with a solid and a mesophase. The solid-like nature of the gels produced, combined with their electro-optical activity, opens the possibility to manufacture flexible TN cells via continuous processes as an alternative to the currently employed batch-type methods.
Studies of Diffusion Losses in Gaseous Media Using a Boundary Condition of the Third Kind
Authors: Ilko Rusinov Ilko Rusinov , Susumu Suzuki Susumu Suzuki , Alexander Blagoev Alexander Blagoev , Haruo Itoh Haruo Itoh
Published: October 2002

The application of two approaches for the simultaneous measurement of diffusion and reflection coefficients of particles in gaseous media is carried out using one and the same data set. Both approaches are based on the analysis of the effective lifetimes of particles measured under different experimental conditions and implement a boundary condition of the third kind. The experimental data used are those of Mg atoms diffusing in neon and argon. These were obtained by a pulsed afterglow technique using a hollow cathode gas discharge. The results obtained after processing the data by the two methods are found to show good agreement.
Experimental Investigations on Ne/CF4 Inductively Coupled Discharges
Authors: Takashi Kimura Takashi Kimura , Kazuyuki Ohe Kazuyuki Ohe
Published: October 2002

A Langmuir probe measurement was applied to an inductively-coupled RF (13.56 MHz) Ne/CF4 discharge over a pressure range from 20 mTorr to 60 mTorr while changing the CF4 content from 5 to 20%, and keeping the power injected into the plasma at about 100 W. The measured electron energy distribution function (EEDF) under any condition deviated from the Maxwellian distribution in the energy region higher than the lowest excitation threshold energy of Ne. The average electron energy, electron density and dissociation rate coefficient estimated using the measured EEDF decreased slightly with increasing CF4 content. The EEDF and the dissociation rate coefficient in Ar/CF4 and Ne/CF4 discharges under an equally injected power were compared. The number of electrons with energy higher than the dissociation threshold energy in Ne/CF4 were much larger than that in Ar/CF4, yielding a difference in dissociation rate coefficient of one order of magnitude.