bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Metal-Organic Vapor Phase Diffusion Enhanced Selective Area Epitaxy, a Novel Metal-Organic Vapor Phase Epitaxy Selective Area Growth Technique, and Its Application to Multi-Mode Interference Device Fabrication
Authors: Bouda Martin , Nakano Yoshiaki
Published: October 2002

For the first time Multi-Mode Interference (MMI) power splitters have been fabricated directly by selective area growth, using a novel metal-organic vapor phase diffusion enhanced selective area epitaxy (MOVE2) process. The MOVE2 process features extremely wide-range in-plane bandgap control, high design flexibility and good uniformity under conventional growth pressure and therefore is very suitable for photonic integration. For bulk InGaAs material in-plane bandgap shifts as large as 200 nm have been obtained. The general incorporation characteristics of both group-III and group-V species in selective area grown InGaAsP have also been determined. The MMI power splitter excess losses were as low as 2 dB, including S-bend losses.
Size-Controlled Formation of Decananometer InGaAs Quantum Wires by Selective Molecular Beam Epitaxy on InP Patterned Substrates
Authors: Muranaka Tsutomu , Okada Hiroshi , Hasegawa HajimeFujikura
Published: October 2002

Detailed scanning electron microscopy (SEM), photoluminescence (PL) and
magnetoresistance measurements were made for InGaAs ridge quantum wires
(QWRs) grown by selective molecular beam epitaxy (MBE) in order to establish a
method for size-controlled formation of high-quality decananometer wires. The
width of our InGaAs ridge QWRs was found to be proportional to the growth time
of the bottom InAlAs layer with a rate of about 9.5 nm/min. A minimum wire
width of about 35 nm was achieved. The wire widths measured by SEM, PL and
magnetoresistance methods agreed reasonably well with each other as well as with
the design values. The results of PL and magnetotransport measurements indicated
that the present decananometer wires possess good crystalline and interface qualities
as well as strong one-dimensional electron confinement. The present method was
concluded to be powerful for size-controlled formation of high-quality
decananometer InGaAs QWRs.
Improved Optical Properties of Strain-Induced Quantum Dots Self-Formed in GaP/InP Short-Period Superlattices
Authors: Fudeta Mayuko , Asahi Hajime , Kim Seong-Jin , Noh Joo-Hyong , Asami Kumiko , Gonda Shun-ichi
Published: October 2002

Optical properties of multilayer quantum dots (MQDs) self-formed in the GaP/InP short-period superlattice (SL)/InGaP multilayer structures are investigated as a function of InGaP barrier thickness (B). Photoluminescence (PL) linewidth broadening with temperature is improved and tends to reduce by decreasing B. This is attributed to the vertical coupling effect between QDs and their vertical alignment. Temperature variation of PL properties shows the exciton behavior. At low temperatures, emissions from both bound exciton and free exciton appear under the weak excitation density condition. Integrated PL intensity is quite stable up to 120 K.
Temperature Dependence of Luminescence Decay Time of InP Quantum Disks
Authors: Okuno Tsuyoshi , Ren Hong-Wen , Sugisaki Mitsuru , Nishi Kenichi , Sugou Shigeo , Masumoto Yasuaki
Published: October 2002

We measured temperature dependence of luminescence decay
time of self-assembled InP dots in GaInP lattice-matched to GaAs.
The radiative lifetime of InP-dot luminescence is independent of
temperature below ∼40 K and is linear with temperature between
∼40 and ∼120 K. These two features in the two temperature
regimes are characteristic of zero-dimensional and two-dimensional
structures, respectively. This temperature behavior of the lifetime
is thought to be caused by the disklike shape of the InP dots; the
dot lateral widths are longer than their heights, and thus they have
an intermediate character between zero-dimension and two-dimensions.
High Breakdown Voltage InAlAs/InGaAs High Electron Mobility Transistors on GaAs with Wide Recess Structure
Authors: Higuchi Katsuhiko , Matsumoto Hidetoshi , Mishima Tomoyoshi , Nakamura Tohru
Published: October 2002

Both an off-state breakdown voltage between a gate and a drain (B
V
gd) and maximum
frequency of oscillation (f
max
) are described as functions of the width of gate recess in an
InAlAs/InGaAs high electron mobility transistor (HEMT), using a new analysis model. The
model suggests that the wide recess structure can improve both B
V
gd and f
max
, which is
experimentally confirmed. We fabricated InAlAs/InGaAs HEMTs lattice-mismatched to GaAs
substrates with optimum recess width, and these exhibited both a high B
V
gd of 14 V and a high f
max

of 127 GHz at a gate length of 0.66 µm.
Low-Power Consumption InGaAs PIN Diode Switches for V-band Applications
Authors: Ziegler Volker , Berg Michael , Tobler Hans , Woelk Claus , Deufel Reinhard , Trasser Andreas , Schumacher Hermann , Alekseev Egor , Pavlidis Dimitris , Dickmann Juergen
Published: October 2002

In this paper, we present the measurement results of two InP-based
coplanar SPST (single pole single throw) PIN diode switches operating at V-band frequencies. The switches show excellent mm-wave performance combined
with a very low DC-power consumption. The SPST with on-chip biasing and
DC-blocking capacitors demonstrates an insertion loss as low as 0.84 dB
and a high isolation value of 21.8 dB at a center frequency of 53 GHz with
only 0.8 mW of DC-power consumption. A more simple SPST exhibits under
equivalent conditions (0.9 mW) an excellent insertion loss of 0.52 dB and
an isolation of 21.7 dB. Furthermore the power-handling capability of the
InGaAs PIN diodes, which are used as active switching elements, is
investigated in this paper and found to exceed 25 dBm at a reverse voltage
of -5 V.
Effect of Annealing on Fatigue Properties of Sb-Doped Lead Zirconate Titanate Thin Films Deposited by DC Reactive Sputtering
Authors: Choi Won-Youl , Kim Ho-Gi
Published: October 2002

The effect of annealing on the ferroelectric properties of
Pt-based thin film capacitors of Sb-doped lead zirconate titanate
[Pt/Pb(Zr0.48Ti0.52)O3/Pt/SiO2/Si] were
investigated. Undoped Pb(Zr0.48Ti0.52)O3 (PZT0) and
Sb-doped Pb(Zr0.48Ti0.52)O3 (PZST07) thin films were
annealed in oxygen atmosphere at 650°C for 30 min. The Sb
cation in a PZT thin film before and after annealing was confirmed
to be trivalent (Sb3+) by X-ray photoelectron spectroscopy
(XPS). The grain sizes of undoped PZT (PZT0) and Sb-doped PZT
(PZST07) thin films after annealing are seen to increase. These
changes of grain size affect the fatigue properties of PZT thin
films. Annealed Sb-doped PZT (PZST07) thin films show good fatigue
behavior (fatigue free up to 1011 switching cycles) and a
larger P
*
r-P
∧
r value (31 µ
C/cm2) than SrBi2Ta2O9 (SBT) thin films.
High Temperature Operation of AlGaInAs Ridge Waveguide Lasers with a p-AlInAs Electron Stopper Layer
Authors: Takemasa Keizo , Munakata Tsutomu , Kobayashi Masao , Wada Hiroshi , Kamijoh Takeshi
Published: October 2002

1.3 µm AlGaInAs/InP ridge waveguide lasers with a p-AlInAs electron stopper layer (ESL) were fabricated and the effect of the ESL was investigated. By inserting an ESL between active and separate confinement heterostructure (SCH) layers, the characteristic temperature of threshold current and slope efficiency were improved, especially in the higher operating temperature range, and the maximum operating temperature under CW operation was improved by 20°C. An excellent CW characteristic temperature of 111 K was obtained with operating temperatures between 20 and 80°C and the record high operating temperature of 210°C was achieved with the 700-µm-long laser under pulse operation. Power reductions at a constant current with increasing temperature were determined at 80°C as -1.27 dB and -1.67 dB under pulse and CW operations, respectively.
Improvement of Characteristic Temperature in In0.81Ga0.19As/InGaAsP Multiple Quantum Well Laser Operating at 1.74 µm for Laser Monitor
Authors: Ubukata Akinori , Dong Jie , Matsumoto Koh
Published: October 2002

InGaAs/InGaAsP compressively strained quantum well lasers operating at 1.74 µm have been fabricated with thin carrier blocking layers sandwiching the active layer for carrier
confinement. A laser characteristic temperature (T
0) of 85 K was obtained, which is the highest value ever reported in InGaAs/InGaAsP lasers in this wavelength range.
Extended Cavity Lasers in InGaAs-InGaAsP and GaInP-AlGaInP Multi-Quantum Well Structure Using a Sputtered SiO2 Technique
Authors: Qiu Bocang , Hamilton Craig J. , Ke Maolong , Kowalski Olek P. , McDougall Stewart D. , Bryce A. Catrina , Marsh John H.
Published: October 2002

Sputtering a thin layer of SiO2 (≈200 nm) followed by high temperature annealing has
recently been found to be very promising in promoting quantum well intermixing. The
intermixing is thought to be due to point defects generated by the sputtering plasma
diffusing through the material during a subsequent high temperature anneal. In this paper,
we describe the technique using the sputtered SiO2 and subsequent high temperature
annealing, either by rapid thermal Annealer (RTA) or CW Nd:YAG laser operated at 1.064 µm. Differential blue shifts of up to 70 meV and 120 meV have been obtained for InGaAs-InGaAsP and GaInP-AlGaInP material systems. Extended cavity lasers have been fabricated and characterised for both material systems.
Reciprocation Characteristics of a Magnet Levitated above a YBa2Cu3Ox Superconductor
Authors: Takeshi Maeda Takeshi Maeda , Muneo Futamura Muneo Futamura , Hajime Konishi Hajime Konishi
Published: October 2002

We measured and analyzed the reciprocating motion of a magnet floated above a YBa2Cu3Ox superconductor.
Frequency dependences of the amplitude and phase of the reciprocation implied that the reciprocating motion has one degree of freedom.
A mechanical model with a mass, a spring, and a dashpot was used to analyze the reciprocation characteristics.
By adding frequency and displacement dependences of the pinning effect to the mechanical model, we obtained good agreement between analytical and experimental results.
Novel Characterization Method of Ions in Liquid Crystal Materials by Complex Dielectric Constant Measurements
Authors: Sawada Atsushi , Tarumi Kazuaki , Naemura Shohei
Published: October 2002

The frequency dependence of the complex dielectric constant of liquid crystal
materials doped with tetra-n-butylammonium iodide (TBAI) is investigated in the
low-frequency region, and the experimental results are analyzed in terms of space
charge polarization. The contribution from an electric double layer is also taken
into consideration in the analysis. By means of curve fitting utilizing theoretical
expressions of the space charge polarization, five sets of diffusion coefficient and
density values are obtained for mobile ions. It is confirmed by experiments on the
temperature dependence that five kinds of ions follow Walden's rule, and verified
from the viewpoint of ion radii that two of the five kinds of ions are TBA+ and I-.
The frequency-dependent dielectric properties, which are characteristic of the
behaviors of ions, can be well explained by this study and the analytical method
introduced here is considered to be powerful for the evaluation of the attributes
of mobile ions.
Comparison of Analytical Calculations to Finite-Difference Time-Domain Simulations of One-Dimensional Spatially Varying Anisotropic Liquid Crystal Structures
Authors: Titus Charles M. , Bos Philip J. , Kelly Jack R. , Gartland Eugene C.
Published: October 2002

There is a need for an accurate optical simulation tool for liquid crystal structures with director variations in
more than one dimension. Finite-difference time-domain (FDTD) computation of Maxwell's equations is
one approach to consider. The FDTD method has been in use in the electrical engineering community for
years, but has only recently been applied to liquid crystal structures. Little is known about the accuracy of
FDTD simulations of typical liquid crystal structures, in which the dielectric tensor can undergo large local
spatial variations. This paper compares FDTD simulations and analytic solutions of two liquid crystal
problems: the twisted-nematic cell and Bragg reflection from a planar cholesteric layer.
The Characterization of Strain vs Field and Crystal Structure for PBNN Piezoelectric Ceramic with Tungsten Bronze Structure
Authors: Chen Chen , Daren Daren , Li Li , Guorong Guorong , Yin Yin , Qingrui Qingrui
Published: October 2002

The characterization of strainSwith electric fieldEwas studied for [Pbx(Ba, Sr)1-x]4(Na0.88Li0.12)2Nb10O30,x=0.64 (abbr. PBNN) piezoelectric ceramic with the tungsten bronze (TB) structure. It was shown that the PBNN possessed excellent linearity ofSvsE, and at a low electric field range there was not a threshold fieldEbexisted, which was an inherent feature for lead zirconate titanate (PZT) system ceramics with peroveskite structure to start producing irreversible motion of 90° domain wall. However, it was found that at a high electric fieldEabout 350 V/mm, a slight increment in the slope rate of theSvsE(that is the piezoelectric coefficientd33ord31) which is difficult to detect, appeared in the curve ofSandE. The characterization ofSwithEfor PBNN ceramic, which ferroelectric phase was a pseudo-orthorhombic belonging to the uniaxis ferroelectrics, was discussed, according to constructed mechanism and influence of two sorts of 90° domain.
Effects of the Two-Step Growth Method for GaAs Grown on CaF2/Si(111) with the Electron Beam Surface Modification Technique
Authors: Koji Kawasaki Koji Kawasaki , Kazuo Tsutsui Kazuo Tsutsui
Published: October 2002

Effects of the two-step growth method
were investigated in epitaxial growth of the GaAs layer
on the CaF2/Si(111) substrate, where the CaF2 surface was modified
by the electron beam exposure technique.
In-situ optical observation of the initial stage of GaAs
growth revealed that sticking coefficient
of GaAs on the CaF2 was low and
GaAs grew with a three-dimensional growth mode
at 550°C or higher,
while the sticking coefficient was increased and
GaAs grew with a two-dimensional mode
at 500°C or lower.
The GaAs layer with good surface morphology
without a twin boundary was obtained by
the two-step growth method
in which the initial layer was grown at less than 500°C and
the succeeding layer was grown at 600°C.
X-ray full-width at half maximum (FWHM) of 400 arcsec and
Hall mobility of electrons more than 2,300 cm2/Vs were obtained
in a 1.5-µm-thick GaAs layer grown by the two-step growth method.
High Performance Media for Phase Change Optical Recording
Authors: Zhou Guo-Fu , Jacobs Bernardus A. J.
Published: October 2002

We discuss various mechanisms that lead to a high crystallization rate of the recording layer in a
phase change disk. The role of interface layers, recording layer composition and its thickness is especially
emphasized. Disks with a data bit rate beyond 40 Mbit/s have been realized.
A High Performance Doppler Interferometer for Advanced Optical Storage Systems
Authors: Lee Chih-Kung , Wu Giin-Yuan , Teng Chao-Ting , Wu Wen-Jong , Hsiao Chi-TingLin , Shih Hsieh-Chin , Wang Jen-Shung , Lin San-Chien , Lin Chan Ching , Lee Ching-Fa , Lin Yen-Chen
Published: October 2002

The design thinking, implementation, and testing results of a
newly developed Doppler interferometer is described. The three
built-in measuring modes including (1) single-beam mode for
measuring absolute vibration, (2) dual-beam for measuring
differential vibration, and (3) distance measuring, are all
presented. To facilitate the application of this interferometer for
advanced optical storage applications, a circular polarization
interferometer configuration was adopted to arrive at a compact size
and to enable the adoption of a built-in microscopic imaging system
that can be used both as an alignment aid and as a sample imaging
system. The configuration of the inherent dynamic system analysis
capabilities that can be used to investigate the Bode plot of
optical storage systems is also examined in detail. The nanometer
resolution and megahertz bandwidth capabilities of this
interferometer were verified in various advanced optical storage
systems related experiments.
Holographic Laser Module with Dual Wavelength for Digital Versatile Disc Optical Heads
Authors: Shih Hsi-Fu , Yang Tzu-Ping , Freeman Mark O. , Wang Jinn-Kang , Yau Hon-Fai , Huang Der-Ray
Published: October 2002

Backward compatibility with CD-R necessitates having two laser sources in the digital versatile disc (DVD) pickup head. The dual-wavelength optical head complicates pickup design and enlarges the volume of the head. Moreover, it increases the number of components and assembly cost. In this paper, we present a new design for a dual-wavelength holographic pickup-head module. Packaged together in the module are two laser diodes, photodiodes and a holographic optical element (HOE) for diffracting reflected light from the disk onto the corresponding photodetectors. This module can be used as the core of an optical head capable of reading DVD, CD and CD-R.
Near-Field Recording Head with Simple Tracking Design
Authors: Huang Der-Ray , Chao Zu-Wen , Wu Guo-Zua , Lean Eric G.
Published: October 2002

A two-zone solid-immersion lens is proposed for use in near-field recording. Two
spots are generated. One illuminates the lower flat plane of the disk for reading/writing
and the other illuminates the upper pregrooved plane of the disk for push-pull tracking.
New Recording Method Combining Thermo-Magnetic Writing and Flux Detection
Authors: Saga Hideki , Nemoto Hiroaki , Takahashi HirofumiSukeda
Published: October 2002

We have developed a new perpendicular thermo-magnetic recording
method coupled with magnetic flux detection. The resolution is
substantially improved by flux detection. Compared to the latest
magneto-optical disk drives, the carrier-to-noise ratio of a
reproduced signal is 5 dB higher, and the recording density reaches
8.3 Gbit/inch2. Moreover, this recording method has a good affinity to
near-field optics, and it is an effective technique for attaining a
higher density beyond the super-paramagnetic limitation in
longitudinal magnetic recording.
Dominant Role of Corner Holes in the Decomposition Process of Silicon Islands on Si(111) Surfaces
Authors: Tadatsugu Hoshino Tadatsugu Hoshino , Tetsuya Ishimaru Tetsuya Ishimaru , Hiroki Kawada Hiroki Kawada , Iwao Ohdomari Iwao Ohdomari
Published: October 2002

The decomposition process of silicon islands deposited on 7×7 reconstructed and “1×1” disordered areas of Si(111) surfaces was observed with an in situ scanning tunneling microscope (STM).
We successfully monitored silicon islands on the 7×7 area gradually decomposing through the loss of a few adatoms with every STM scan.
The smallest island just before the complete decomposition always has a corner hole configuration where Si adatoms are arranged in a ring-shaped formation.
Corner holes are also observed for silicon islands deposited on the disordered “1×1” area.
The corner hole is maintained even on the “1×1” area until the last moment before the complete decomposition of the silicon island.
Impact of Spherical Aberrations on Printing Characteristics of Irregularly Aligned Patterns of Alternating Phase Shift Mask
Authors: Nakao Shuji , Nakae Akihiro , Tsujita Kouichirou , Wakamiya Wataru
Published: October 2002

The printing characteristics of irregularly aligned patterns
with alternating phase shift masks (PSMs) and the impact of
spherical aberration on these characteristics are investigated by
experiments and calculations of optical images. In experiments,
very poor printing characteristics are observed for particular
irregularly aligned patterns, even if there is no phase
contradiction in the layout of the patterns. These patterns show
small depth of focus (DOF) and/or poor mask fidelity. The phenomena
are analyzed by beam configurations in interference and calculated
optical images. For some patterns, the defocus characteristics are
essentially poor even in non-aberrated optics. For some other
patterns, the spherical aberration degrades the characteristics
significantly, while non-aberrated characteristics are not so poor.
In the application of alternating PSMs for device pattern formation,
it is important to consider the pattern layout and lens aberration.
Leakage Current Reduction of Chemical-Vapor-Deposited Ta2O5Films on Rugged Polycrystalline Silicon Electrode for Dynamic Random Access Memory Application
Authors: Lin Mark , Chang Chun-Yen , Huang Tiao-Yuan , Shieh Win-Yi
Published: October 2002

In this paper we describe the electrical and physical characterizations of Ta2O5films on rapid thermal nitrided (RTN) rugged polycrystalline silicon electrodes for 256 M dynamic random access memory (DRAM) application. To overcome the higher leakage on Ta2O5films with rugged poly-Si bottom electrodes, we have successfully employed a light oxidation on rugged poly-Si grains for improving the acute angle of surface morphology, and a post-treatment with rapid thermal nitridation of N2O on Ta2O5films to reduce the leakage. In addition, a RTN pre-treatment is also applied to prevent rugged poly-Si oxidation during a Ta2O5film deposition that compromises the effective Ta2O5thickness. Our results show that Ta2O5film with an effective thickness of 1.4 nm (physical thickness=10 nm) and a low leakage current density of less than 1×10-8A/cm2, suitable for 256 M DRAM application, can be achieved. Our results also show that while a light oxidation on rugged poly-Si grains could improve the acute angle between the rugged poly-Si and its congruent amorphous silicon sub-layer, over oxidation on rugged poly-Si grains could degrade the leakage current and the time dependent dielectric breakdown (TDDB) characteristics of the stacked capacitor.
A Static Model for Scratches Generated during Aluminum Chemical-Mechanical Polishing Process: Orbital Technology
Authors: Zhong Lei , Yang Jerry , Holland Karey , Grillaert Joost , Devriend Katia , Heylen Nancy , Meuris Marc
Published: October 2002

In this work, we explored the analogy between the scratches formed on a polished surface and the
indentation used in the material hardness testing. A static hardness model proposed on the basis of this
analogy is able to explain quite successfully the experimental results such as the depth of the scratches and
the vulnerability of the aluminum film, under the assumption that the particle penetration is facilitated by
a stress concentration. It is suggested that the stress redistribution needed might be caused by the
incompleteness of pad-wafer contact due to the pad surface roughness. We also found that a scratch in its
plane-view is shaped by the kinetic equation governing the pad-wafer relative movement, which is deemed
as a further evidence for our hypothesis that a scratch is generated by a protrusion on the pad holding a
particle against the wafer and forcing it into the film with the aid of the stress concentration.
Oscillations of Negative Polarization in Secondary Electrons Emitted from Au/Fe(110)
Authors: Furukawa Takashi , Koike Kazuyuki
Published: October 2002

To study the oscillatory interlayer magnetic coupling through
epitaxial Au thin films, we investigated the polarization oscillation
of secondary electrons emitted from a Au(111)/Fe(110)
surface. Comparing the polarization of secondary electrons as a
function of the Au thickness for Au(111)/Fe(110) and for
Au(001)/Fe(001), we found that the polarization of conduction
electrons in Au(111) thin films
always oscillates with negative
polarity. This result shows that the density of quantum-well states
for the majority-spin electrons is lower than that for the
minority-spin ones independent of the
Au film thickness.
Glancing-Angle Electron Beam Bombardment for Modification of GaN Epilayer Growth using Plasma-Assisted Molecular Beam Epitaxy
Authors: Shim Kyu-Hwan , Paek Mun-Cheol , Cho Kyoung-Ik
Published: October 2002

We report the observation of significant enhancement in the structural and
electrical properties of GaN epilayers grown by utilizing electron-beam (EB)
irradiation; EB bombardment was successfully employed to achieve a high-quality
GaN epilayer at a growth rate as high as 0.6 µm/h at a low temperature of 680°C.
EB irradiation resulted in a marked reduction of dislocation density with smoother
surfaces and a decrease in carrier concentration of approximately one order of magnitude.
Hybrid Circuit Simulator Including a Model for Single Electron Tunneling Devices
Authors: Masaharu Kirihara Masaharu Kirihara , Kazuo Nakazato Kazuo Nakazato , Mathias Wagner Mathias Wagner
Published: October 2002

A hybrid circuit simulator has been developed that
incorporates elements of single electron devices
into the conventional circuit simulator SPICE
(Simulation Program with Integrated Circuit Emphasis).
The elements can consist of an arbitrary network
of tunnel junctions and capacitors,
whose characteristics are calculated
using a master equation method.
By employing the hybrid circuit simulator,
we studied a turnstile device
feeding the input
of a complementary metal-oxide-semiconductor (CMOS) inverter,
and were able to more successfully demonstrate
the transfer of electrons through the turnstile one by one
in SPICE.
Electrical Properties of SrBi2Ta2O9/Insulator/Si Structures with Various Insulators
Authors: Lee Won-Jae , Shin Chang-Ho , Cho Chae-Ryong , Lyu Jong-Sun , Kim Bo-Woo , Yu Byoung-Gon , Cho Kyoung-Ik
Published: October 2002

The electrical properties of metal/ferroelectric/insulator/semiconductor (MFIS) structures with various insulators were investigated. Layers of Si3N4/SiO2 (NO) formed by thermal oxidation and low pressure chemical vapor deposition (LPCVD) and Al2O3 layers deposited by atomic layer deposition (ALD) were used as inter-dielectric layers. SrBi2Ta2O9 (SBT) films used as ferroelectric layers were prepared by metal organic decomposition (MOD). The capacitance-voltage (C–V) curves including the memory window were affected by varying the annealing temperature for SBT films. Memory windows for MFIS structures with NO inter-dielectrics in the range of 0.75–1.2 V were maintained up to annealing temperatures of 900°C. The width of the memory window in C–V curves for MFISs using thin Al2O3 layers decreases with increasing annealing temperature. Therefore, the selection of a good insulator and parameter control are required for the use of MFIS-ferroelectric random access memories (FRAMs).
Gas Evaporation of Zinc under Low Gravity with a Drop Capsule
Authors: Masaya Sengoku Masaya Sengoku , Shinya Sawai Shinya Sawai , Minoru Dohi Minoru Dohi
Published: October 2002

Fine zinc particles were produced in an argon gas atmosphere and in a helium gas atmosphere of 1.33 ×104 Pa without thermal convection. To investigate the initial process of crystal growth, particles deposited at various places and at different moments during evaporation were collected. The shape and size of the particles were observed using a scanning electron microscope. When the evaporation time increased, the mean size of the deposited particles decreased in the argon gas atmosphere, while it increased in the helium gas atmosphere. These experimental results can be interpreted in terms of the assumption that nucleation and crystal growth are dominated only by the diffusion of vapor from the evaporation source.
Kinetic Analysis on Crystallization of Bi 2Sr 2CaCu 2O 8 from Its Glassy State
Authors: Suzuki Takuya , Yumoto Ken-ichi , Hasegawa Masashi , Takei Humihiko
Published: October 2002

The crystallization of Bi2Sr2CuO
x
(Bi-2201) and Bi2Sr2CaCu2O
x
(Bi-2212) from powdered Bi–Sr–Ca–Cu–O glasses having a composition of Bi2Sr2CaCu2O
x
by annealing up to 600°C in air is investigated using a high-temperature X-ray diffraction apparatus with a rapid counting and analyzing system. The initial crystallization of the above two phases appears at the first stage within 5 min of heating and no further increase in the amount of Bi-2201 is observed. Between 500 and 600°C, the amount of Bi-2212 gradually increases with the soaking time after the initial rapid crystallization. The kinetic analyses of the data in this temperature range have revealed that an activation energy of 70.8 kJmol-1 is required for Bi-2212 crystallization, which may be controlled by oxidation of Cu(I) to Cu(II).
Calibration of Time- and Space-Resolving Vacuum Ultraviolet Spectrograph for Plasma Diagnostics in the Tandem Mirror GAMMA 10
Authors: Yoshikawa Masayuki , Ikeda Katsunori , Kawamori YuujiOkamoto , Ito Takahiro , Yamaguchi Naohiro , Tamano AtsushiMase , Yatsu Kiyoshi
Published: October 2002

A time- and space-resolving vacuum ultraviolet (VUV) spectrograph has been
developed and is applied as an impurity diagnostic in the tandem mirror GAMMA 10.
The VUV spectrograph enables us to analyze the spatial distributions of plasma radiation
in the wavelength range from 15 nm to 105 nm. Calibration of the VUV spectrograph
was carried out in order to determine the sensitivity of the spectrograph as a function of
wavelength. We also established a method of analyzing the emissivity profiles of each
spectral source in a visual manner from spatially resolved VUV spectrophotograph in the
GAMMA 10.
A New Polarimeter for Dilute Aqueous Solutions: The Improved Null-Method Compensation for the Optical Rotatory Power by the Faraday Effect of a Sample
Authors: Mitsui Takahisa , Kinugawa Tohru , Sakurai Katsumi
Published: October 2002

We propose a new polarimeter for the null-method measurement that utilizes the Faraday effect of a sample, i.e., dilute aqueous solutions in our case. With replacement of the Faraday glass that has been used in the conventional null-method polarimeter with our sample, our improved method is completely free from the defects of Faraday glass such as the scattering center and the strain-induced birefringence. Furthermore, the optical rotatory power of a sample is determined, in principle, to be independent of the cell length. As a demonstrative experiment, the optical rotatory power of dilute glucose aqueous solutions was successfully measured.
Investigation and Comparison of the Noise in the Gate and Substrate Current after Soft-Breakdown
Authors: Crupi Felice , Degraeve Robin , Groeseneken Guido , Nigam Tanya , Maes Herman
Published: October 2002

Random telegraph signal after soft-breakdown is explained by the capture-emission of electrons in the same oxide traps of the soft-breakdown path. It
is shown that not only the gate current noise, but also the substrate current
noise largely increase at the soft-breakdown moment in n-channel
metal-oxide-semiconductor field effect transistor (nMOSFET) stressed
with positive gate polarity. A strong correlation of the noise in the gate and
substrate current is reported.
Realization of Adaptive Learning Function in a Neuron Circuit Using Metal/Ferroelectric (SrBi2Ta2O9)/Semiconductor Field Effect Transistor (MFSFET)
Authors: Sung-Min Yoon Sung-Min Yoon , Eisuke Tokumitsu Eisuke Tokumitsu , Hiroshi Ishiwara Hiroshi Ishiwara
Published: October 2002

The adaptive-learning function was successfully demonstrated in a neuron circuit using a metal/ferroelectric/semiconductor field effect transistor (MFSFET). The polarization direction of the ferroelectric gate film (SrBi2Ta2O9) of MFSFET was gradually reversed by applying a number of input pulses with a sufficiently short duration of 20 ns. Consequently, the S-D (source-drain) resistance of MFSFET was gradually changed, and the output pulse frequency of the neuron circuit was modulated by the number of input pulses.
Buried Layer Engineering to Reduce the Drain-Induced Barrier Lowering of Sub-0.05 µm SOI-MOSFET
Authors: Risho Koh Risho Koh
Published: October 2002

The influence of the buried layer structure on the drain-induced barrier lowering (DIBL) is investigated for a silicon-on-insulator metal-oxide-silicon field-effect-transistor (SOI-MOSFET) by a two-dimensional device simulator. The buried layer thickness and the dielectric constant of the buried layer are varied systematically. It is found that the degradation on the threshold voltage can be separated into two components. One component originates from the electric flux via the SOI layer and the other via the buried layer. The buried insulator engineering which controls the thickness and the dielectric constant of the buried layer is effective in reducing the latter component. The gate length limit can be reduced by 23% by the buried air gap structure where the dielectric constant of the buried layer is 1.0.
A Novel Shallow Trench Isolation with Mini-Spacer Technology
Authors: Yeh Wen-Kuan , Lin Tony , Chou ComingChen , Sun Shin-Wei
Published: October 2002

A new shallow trench isolation (STI) process with a mini-spacer at the
masking nitride sidewall before silicon trench etching was proposed. With
this mini-spacer, thicker corner liner oxide and a T-shaped trench oxide
can be formed simultaneously. The issue of oxide-recess at STI corner
can be effectively reduced and larger process window for subthreshold
kink free device were obtained. The isolation capability and junction
integrity were both improved as compared with those of the conventional
STI process. Reverse narrow width effect as well as gate oxide integrity
were also improved. This technology was employed for 0.13 µm
complementary metal oxide silicon (CMOS)
device fabrication.
Plasma Parameter Measurement by the Impedance of a Coil Inductively Coupled with a Plasma
Authors: Misono Katsuhide , Kando Masashi , Verdeyen Joseph T.
Published: October 2002

We have developed a method to measure plasma parameters in a discharge by
analyzing the impedance of a search coil wound around a discharge tube. This
technique is
based on the diamagnetic characteristic of the plasma. When a high-frequency current
passes through the search coil, a diamagnetic current is induced inside the plasma, and the
energy to the search coil is dissipated by Joule loss due to the resistivity of the plasma.
As a result, the impedance of the search coil varies depending on plasma properties. The
relationship among plasma parameters, magnetic field and impedance of the search
coil is derived from Maxwell's equations and generalized Ohm's law. Thus, plasma
parameters can be determined from the variation of the impedance. The present diagnostic method was
applied to measure electron density and electron temperature in a mercury-argon
plasma at a pressure of 2.5 Torr.
Evaluation of Interface SiOx Transition Layer in Ultrathin SiO2 Film by Oscillatory Tunneling Current-Voltage Characteristics in Photo-CVD SiO2-Si Diode
Authors: Osamu Maida Osamu Maida , Norio Okada Norio Okada , Takeshi Kanashima Takeshi Kanashima , Masanori Okuyama Masanori Okuyama
Published: October 2002

The interface transition layer in ultrathin SiO2 film is characterized by analyzing the oscillatory tunneling current. SiO2 thin films are deposited on atomically flat Si at low temperature (300°C) by photo-induced chemical vapor deposition (photo-CVD) and their electrical characteristics are investigated. The electrical characteristics of the SiO2/Si diode are improved by annealing in O2 atmosphere under ultraviolet irradiation, and the current becomes small and equivalent to that of a thermally grown oxide. Tunneling current through the ultrathin gate oxide is observed to exhibit oscillatory behavior in the Fowler-Nordheim (FN) tunneling region, which results from the interference of the incident and reflected electron waves at the SiO2/Si interface. It is clarified from theoretical calculation of the tunneling current that the amplitude and phase of the oscillatory current are strongly affected by the transition layer thickness. It is concluded that the interface transition layer of photo-CVD SiO2 film is thinner than that of thermally grown SiO2 film from analysis of the amplitude of the oscillatory profile.
Si Atomic-Layer Epitaxy Using Thermally Cracked Si2H6
Authors: Yoshiyuki Suda Yoshiyuki Suda , Yasuhiro Misato Yasuhiro Misato , Daiju Shiratori Daiju Shiratori
Published: October 2002

We propose a novel atomic-layer epitaxy (ALE) method for group IV element semiconductors with which thermally cracked hydride molecules are applied as a precursor. We demonstrate for the first time that with thermally cracked Si2H6 as a precursor, monolayer-by-monolayer Si ALE growth is successfully realized on Ge(001). The results also indicate that Si ALE growth is realized on both Si(001) and Ge(001).
A Novel Clean Ti Salicide Process Using Grooved Gate Structure
Authors: Hizawa Kazuya , Nishikawa Hideaki Matsuhashi andSatoshi
Published: October 2002

It is demonstrated that dry etching and Ar sputtering for Si
surface cleaning cause phase transition failures of TiSi2 and
degradation of the resistivity. We propose a Ti self-aligned-silicide
(salicide) process using a grooved gate structure. In this technique,
poly-Si is patterned by an oxide mask. The oxide layer protects the
gate surface from contamination by dry etching for sidewall
formation. Before Ti deposition, the poly-Si surface is not sputtered
by Ar to clean the surface. As a result, TiSi2 agglomeration was
suppressed drastically in comparison with the conventional gate
structure.
Facet-Free Si Selective Epitaxial Growth Adaptable to Elevated Source/Drain MOSFETs with Narrow Shallow Trench Isolation
Authors: Miyano Kiyotaka , Mizushima Ichiro , Hokazono KazuyaOhuchi , Tsunashima Yoshitaka
Published: October 2002

A novel selective epitaxial growth (SEG) process that realizes a facet-free elevated source/drain
(S/D) is proposed. The key points are the appropriate selection of the gate-sidewall material and its
structural improvement. It was observed that the facet was not formed adjacent to SiN in contrast
to the SiO2 case. Therefore, SiN is selected as a gate-sidewall. The novel gate-sidewall is
constructed from a SiN sidewall and SiO2 liner layer which acts as a sidewall reactive ion etching
(RIE) stopper. The SiO2 liner layer is lateral etched by wet treatment. By the SEG process, the
facet, which is formed adjacent to the SiO2 liner is screened out within the lateral etched region, and
no facet is observed along the SiN sidewall. Si lateral overgrowth on the shallow trench isolation
(STI) region was also confirmed to be controllable in the facet-free SEG process. This novel SEG
process was found to be successfully adapted to facet-free elevated S/D.
Atomic-Layer Doping in Si1-xGex/Si/Si1-xGex Heterostructures by Two-Step Solid-Phase Epitaxy
Authors: Sugii Nobuyuki , Nakagawa Kiyokazu , Yamaguchi Shinya , Miyao Masanobu
Published: October 2002

A two-step solid-phase epitaxy (SPE) technique was developed to
solve the problem of Sb segregation during the growth of
Si1-x
Ge
x
/Si/Si1-x
Ge
x
heterostructures with Sb
atomic-layer doping. At below 100°C Sb was deposited onto the
Si1-x
Ge
x
layer crystallized in the first SPE process to
eliminate the diffusion of Sb during the second SPE process to form
the Si1-x
Ge
x
layer on the Sb layer. As a result, a sharp
Sb depth profile and high electrical activation in the Sb-doped
Si1-x
Ge
x
layer was obtained. However, the number of
modulation-doped carriers in the Si channel layer was small.
Calculation of the carrier distribution between the channel and the
doped layer suggested that the carrier density in the channel was low
when the Sb-doping profile was sharp, thus precise control of the
modulation-doped-carrier density by optimizing the thickness of the
Sb-doped layer is crucial for fabricating modulation-doped
field-effect transistors.
Influence of Microscopic Chemical Reactions on the Preparation of an Oxide-Free Silicon Surface in a Fluorine-Based Solution
Authors: Sugita Yoshihiro , Watanabe Satoru
Published: October 2002

It is shown that microscopic chemical reactions influence the
hydrogen termination of the Si surface in fluorine-based solution.
The hydrogen termination reaction was quite sensitive to the surface
structure and the composition of the solution. The remaining hydroxyl
group on some specific surface sites was suppressed using a neutral pH
solution. It was confirmed that the neutral pH solution was suitable
for silicidation on a heavily boron-implanted surface and improved the
sheet resistance of titanium silicide on the surface.
A Long-Wavelength Infrared Photodetector with Self-Organized InAs Quantum Dots Embedded on HEMT-Like Structure
Authors: Cho Taehee , Kim Jong-Wook , Choe Jae-EungOh , SongcheolHong SongcheolHong
Published: October 2002

We fabricated a quantum dot infrared photodetector (QDIP) with 5-stacked self-organized InAs quantum dots embedded in a high electron mobility transistor-like
modulation doped structure and utilize lateral electron transport. A peak response of the
QDIP appeared at λ=10.5 µm at T=80 K. We also found
that the device exhibits bias-dependent responsivity.
A Si Memory Device Composed of a One-Dimensional Metal-Oxide-Semiconductor Field-Effect-Transistor Switch and a Single-Electron-Transistor Detector
Authors: Takahashi Yasuo , Fujiwara Akira , Yamazaki Kenji , Namatsu Hideo , Kurihara Kenji , Murase Katsumi
Published: October 2002

A novel Si memory device composed of a small one-dimensional (1D) Si-wire metal-oxide-semiconductor (MOS) field-effect transistor (FET) and a single-electron transistor (SET) is
proposed, and its fundamental characteristics at 40 K are demonstrated. The small Si SET is
fabricated by means of pattern-dependent oxidation (PADOX), which is almost completely
compatible with Si MOSLSI processes. The 1D MOSFET provides a very steep subthreshold
slope that is very close to the physical limit at room temperature in spite of the very short channel. This guarantees low voltage operation as well as small size. The memory device uses a 1D
MOSFET as a switch for electrons transported to and from the memory node. The very small
number of stored electrons is detected by a highly sensitive SET electrometer. The device can
operate with an extremely small number of electrons, which assures ultralow-power and high-speed operation.
Bidirectional Signal Transmission Circuit Using Single Electron Tunneling Junctions
Authors: Kouichirou Yamamura Kouichirou Yamamura , Yoshiyuki Suda Yoshiyuki Suda
Published: October 2002

We propose a novel bidirectional signal transmission circuit consisting of capacitors and single-electron tunneling junctions. The characteristics of this circuit are that the signal transmission behavior is active and it transmits a signal without any transmission loss, in principle. Using the Monte Carlo simulation, we demonstrate that the circuit functions as a bidirectional signal transmission circuit and is also capable of signal transmission branching. Since this circuit has a simple configuration with the fan-out being easily increased and the transmission direction being easily controlled, the circuit is expected to be widely applied to single-electron integrated circuits.
Transport Properties of a Resistively-Coupled Single-Electron Transistor
Authors: Wakaya Fujio , Kitamura Kazuki , Iwabuchi Shuichi , Gamo Kenji
Published: October 2002

A resistively-coupled single-electron transistor (R-SET),
whose gate was a tunnel resistor,
was fabricated using a modulation-doped GaAs/AlGaAs heterostructure and
metal Schottky gates.
Observed current-voltage characteristics show the Coulomb diamonds
which are predicted for an R-SET.
This means that the tunnel resistor can be used as an R-SET gate.
Detection of Particles on Quarter µm Thick or Thinner SOI Wafers
Authors: Kuwabara Susumu , Mitani Kiyoshi , Kato YasuoYatsugake
Published: October 2002

It was shown that as a probe for a particle detection system
based on the principle of light scattering a 430 nm laser was
effective for detecting particles on thin silicon on insulator (SOI)
wafers. In particular, a p-polarized oblique incident light beam was
more effective than that at normal incidence. This laser was suitable
for an SOI structure of down to 0.2 µm SOI layer and 0.2 µm
buried oxide (BOX) layer. In addition, it is predicted in terms
of the reflectivity of a 430 nm laser that there are the suitable BOX
thicknesses in SOI structure of less than 0.1 µm SOI layer
thickness.
High-Current and High-Transconductance Self-Aligned P+-GaAs Junction HFET of Complete Enhancement-Mode Operation
Authors: Nishii Katsunori , Nishitsuji Mitsuru , Yokoyama Takahiro , Yamamoto Shinji , Tamura Akiyoshi , Inoue Kaoru
Published: October 2002

High-current and high-transconductance self-aligned p+-GaAs junction HFETs (PJ-HFETs) of a
complete enhancement-mode operation have been developed for the first time. Due to the
advantages of the p/n junction, the barrier height of 1.12 eV has been obtained. To obtain high
activation for the Si implanted epitaxial layers, we optimized the
annealing conditions. The 0.8 µm-gate complete enhancement mode PJ-HFET with a large forward gate voltage swing of
more than 1.5 V exhibited a K-value of 400 mS/Vmm, a maximum transconductance (g
m
MAX)
of 410 mS/mm and a maximum drain current (I
MAX) of 380 mA/mm with a threshold voltage
(V
th) of 0.2 V. The standard deviation of V
th was 18.4 mV across a 3 inch wafer. Operated with
a drain bias of 3.3 V, the PJ-HFET demonstrated a power-added efficiency (PAE) of 39.5% with
an adjacent channel leakage ratio (ACPR) of -57.4 dBc at an output power (P
out) of 21.5 dBm
and a frequency of 1.9 GHz.
Device Characteristics of Organic Static Induction Transistor Using Copper Phthalocyanine Films and Al Gate Electrode
Authors: Wang Dong Xing , Tanaka Yasuhiro , Iizuka Masaaki , Kuniyoshi Shigekazu , Kudo Kazuhiro , Tanaka Kuniaki
Published: October 2002

We have fabricated organic static induction transistors (SITs) using copper
phthalocyanine (CuPc) films. The organic SITs have a layered structure of Au (drain)/CuPc/Al (gate)/CuPc/Au (source)/glass. The electrical characteristics of SITs show
that the source-drain current is controlled by the bias voltage applied to the Al gate
electrode and a typical SIT operation with unsaturated current characteristics is
examined. Furthermore, excellent characteristics such as low voltage and high speed
operation as organic transistors are obtained by choosing an appropriate thickness for
each layer.
Stress-Induced Leakage Current and Lateral Nonuniform Charge Generation in Thermal Oxides Subjected to Negative-Gate-Voltage Impulse Stressing
Authors: Lim Peng Soon , Chim Wai Kin
Published: October 2002

High-field stressing of gate oxides can lead to an increase in
the stress-induced leakage current (SILC), which could impose a
potential scaling limitation for tunnel oxide applications in
nonvolatile semiconductor memories. In this article, we report on
positive lateral nonuniform (LNU) charge generation and hole trapping
in silicon dioxide subjected to negative-gate-voltage, high-field
impulse stressing, and the correlation of the LNU charge to the
SILC. The LNU charge and SILC can be electrically annealed through
repeated measurements of the gate current density vs gate voltage
characteristics, or using either a constant voltage or constant
current stress step. Electrical annealing studies show that the
positive LNU charge is located close to the oxide-silicon interface
and is distributed with a certain minimum energy level. A critical
fluence or gate voltage has to be applied before significant LNU
charge annealing is observed.
Effects of Annealing on Type Converted Si and Space Solar Cells Irradiated with Heavy Fluence 1 MeV Electrons
Authors: Khan Aurangzeb , Yamaguchi Masafumi , Taylor Stephen J. , Hisamatsu Tadashi , Matsuda Sumio
Published: October 2002

We present a detailed quantitative study of the thermal annealing characteristics of deep level
defects in Si and space solar cells with boron-doped p-Si base layer, introduced by 1 MeV electrons
irradiation. Present isochronal annealing provides an overall different annealing behavior of the
defects in type converted (n-type) heavy dose electrons (φ=1×1017 e/cm2) irradiated samples,
contrary to earlier low dose electrons studies. Isochronal annealing provides evidence that the
minority carrier trap (E
C-0.18 eV) and majority carrier trap (E
C-0.71 eV) that appear after type conversion play a dominant role in carrier removal and are the major defects responsible for the
type conversion as well as the severe degradation of space solar cells. This study also sheds light on
the fact that heavy electron irradiation not only changes the structure of the device (p to n-type) but
also makes the defect structure more complex as compared to simple defects structure in low dose
samples.