bluuebunny/crossref_metadata_2025 huggingface dataset:
Transition of Absorption Spectra due to Electron-Electron Interaction in a Square-Well Quantum Dot under a Magnetic Field
Authors: Ugajin Ryuichi
Published: October 2002

The far-infrared absorption spectra of three interacting electrons in a square-well quantum dot are strongly influenced by an applied magnetic field; specifically, there are transitions due to electron-electron interaction. These transitions occur because the parity and the spin of the ground state of three interacting electrons change as the magnetic field increases.
In-Situ Observation of the Electrical Conductivity upon Release and Uptake of Oxygen in Indium Tin Oxide Sinter
Authors: Omata Takahisa , Fujiwara Hiroyuki , Otsuka-Yao-Matsuo Shinya , Ono Naoki
Published: October 2002

The electrical conductivity, the oxygen release and uptake of sintered indium tin oxide (ITO) upon heating and cooling under the condition that P(O2)/P
*=4.9×10-4 (P
*=atmospheric pressure), when P(O2) was approximately 50 Pa, were simultaneously observed. Two kinds of oxygen release and uptake were detected in the different temperature ranges of 973<T<1130 K and 1130<T<1273 K. Electrical conductivity was increased as a result of the increase in carrier concentration due to oxygen release at the higher temperature, although the conductivity was not altered by the oxygen release at the lower temperature. Decrease in the mobility of conduction electrons could be explained in terms of the increase in the concentration of the scattering centers induced by release and uptake of oxygen atoms.
Rapid-Thermal-Processed BaTiO3 Thin Films Deposited by Liquid-Source Misted Chemical Deposition
Authors: Horng Ray-Hua , Wuu Dong-Sing , Chan Shih-Hsiung , Chiang Ming-Chung , Huang Tiao-Yuan , Sze Simon Min
Published: October 2002

BaTiO3 thin films deposited on the RuO2(250 nm)/Ru(20 nm)/TiN(200 nm)/Ti(20 nm)/(100)Si substrates by liquid-source misted chemical deposition are reported. The rapid thermal processing (RTP) technique was used for post deposition annealing. It was found that the strain was released and grain size increased for BaTiO3 films treated at high RTP temperature or for long RTP time. The interface between BaTiO3 and the bottom electrode was still sharp for the RTP-treated sample at 950°C. The leakage current density decreases as the RTP temperature increases. It can be decreased to 2.09 nA/cm2 under a supply voltage of 1.5 V. The dielectric constant can be increased up to 250 measured at 100 kHz for the sample treated by RTP at 950°C. The improvements in the BaTiO3 characteristics are due to the fact that RTP can enhance the crystallinity, relax the strain, alleviate the impurities in the films and does not result in significant interdiffusion of the materials.
Achromatic Normally Black Twisted Nematic Device with Wide Viewing Angle Using Negative-in-plane Compensation Films
Authors: Sergan Tatiana , Liu Weimin , Kelly Jack , Yoshimi Hiroyuki
Published: October 2002

We have approximated the uniformly twisted structure of an ideal compensator for the dark state of a normally black twisted nematic (NBTN) device by stacking several layers of a polymer film having in-plane negative birefringence. It was found from modeling that 4 layers are enough to achieve high contrast and reasonable achromaticity. The computer simulation was supported by measurements of optical performance of compensated single and dual domain TN devices. Head-on contrast of greater than 200:1 is achieved with contrast greater than 20:1 in nearly all viewing directions out to polar angles of 60° for o-mode operation, accompanied by grayscale improvement.
Effect of Distribution of Free Volume on Concentration Dependence of Dielectric Relaxation in Water Mixtures with Poly(Ethylene Glycol) and Glucose
Authors: Kakizaki Maeko , Hideshima Teruo
Published: October 2002

A marked concentration dependence of the shape of loss-permittivity-vs-frequency curve for water mixtures with poly(ethylene glycol) and glucose is explained by a theory which assumes a distribution of free volume and relaxation time which is described by the Doolittle equation. This result demonstrates that the theory successfully used to explain temperature dependence of the shape of loss curve can be applied to the case of its concentration dependence as well.
Ba–Mg–W–Ti–O Ceramics with Temperature-Stable Low Microwave Loss
Authors: Takahashi Hiromi , Ayusawa Kazutoshi , Sakamoto Nobuyoshi
Published: October 2002

Ba–Mg–W–Ti–O ceramics have been developed for a dielectric resonator at microwave frequencies. The specimens were investigated by X-ray diffraction (XRD) analysis. The ceramics were calcined at 1200°C for 2 h and sintered at 1500°C for 6 h. We found that the excellent temperature coefficient of the resonant frequency (τf) of +0.8 ppm/°C was obtained at BaO+0.32MgO+0.26WO3+0.42TiO2. [ε
r=21.5, Q×f=49000 (GHz)] In the case of the composition of BaO+0.32MgO+yWO3+zTiO2 (y+z=0.68), τf gradually changed from a negative value to zero following the increase of Z from 0.36 to 0.42. The intensity ratio of I
(002)/I
(220) of XRD which exhibits the Mg–W–Ti ordered B-site sublattice at the Ba(Mg, W, Ti)O3 ceramic was reduced with the increasing of Z. However, at z=0.43, the BaTiO3 secondary phase was observed and τf increased drastically to +33.7 ppm/°C, while Q×f decreased to 19500 (GHz).
Measurement of Hydrogen Diffusivity in Aluminum and a Dilute Alloy by Thermal Evolution Spectroscopy
Authors: Shin-ichirou Hayashi Shin-ichirou Hayashi
Published: October 2002

The introduction of hydrogen into aluminum by mechanical abrasion which has been investigated in our previous paper [S. Hayashi: Jpn. J. Appl. Phys. 35 (1996) 6191] is applied to the determination of hydrogen diffusivity in high purity aluminum and Al-1000at.ppmSi dilute alloy by coupling with thermal evolution spectroscopy (TES). The obtained diffusivity in high purity aluminum is expressed by D (m2/s) = 3.0(±0.5)×10-6exp
(-30(±1) (kJ/mol)/R
T). The diffusivity is larger than the values reported previously by other authors. This suggests that the interstitial mechanism is dominant for hydrogen diffusion in high purity aluminum even in the low temperature region. A similar measurement was performed on Al–1000at.ppmSi dilute alloy. From the analysis using the trap-detrap model, the binding energy of a hydrogen atom with a silicon atom in aluminum is estimated as 16 kJ/mol. This result shows that silicon atoms in aluminum serve as weak trapping centers.
Characteristics of Pb(Zr0.53Ti0.47)O3 Films Deposited by Metalorganic Decomposition on Pt/Ti/TiO2/polysilicon/Si3N4/Si for Pizoelectric Microelectromechanical System Devices
Authors: Kim Joon Han , Yoon Young Soo , Polla Dennis L.
Published: October 2002

Pb(Zr0.53Ti0.47)O3 (PZT) films have been deposited on Pt/Ti/SiO2 and Pt/Ti/TiO2/polysilicon/ Si3N4/Si substrates. In the case of the Pt/Ti/TiO2/polysilicon/Si3N4/Si substrate, there are two different polycrystalline silicon layers. One has been postthermal annealed at 950°C for 30 min and the other has not had any thermal treatment after the deposition of the polycrystalline silicon. The hysteresis curve, piezoelectric coefficient (d
33) and dielectric constant of the as-grown film were measured to characterize the electrical properties. Wide angle X-ray diffraction patterns and cross-sectional images of the films were used to investigate the structural properties. The d
33 of the PZT thin film on substrate A, which was postannealed at 950°C for 30 min after deposition of polycrystalline silicon, was measured to be 158 pm/V by the single beam laser interferometer method. A low frequency relative dielectric constant was 829. Remanent polarization and coercive field of the film on the substrate A were 39.5 C/cm2 and 65.2 kV/cm, respectively. In addition, the interface of the PZT thin film on substrate A was more dense than that on substrate B, which was not postannealed after the deposition of polycrystalline silicon. This interface structure is very important during a chemical etching step. These results suggested that the substrate A is a very promising structure for microelectromechanical system devices based on the PZT thin film.
Ionization-Assisted Deposition of 8-Hydroxyquinoline Aluminum for Organic Light Emitting Diode
Authors: Usui Hiroaki , Tanaka Kuniaki , Orito Hiroyuki , Sugiyama Shinich
Published: October 2002

Ionization-assisted deposition (IAD) was applied for the preparation of 8-hydroxyquinoline aluminum (Alq) in the fabrication of organic light-emitting diodes (LEDs) in the structure of indium-tin-oxide glass/spin-coated polyvinylcarbazole (PVCz)/Alq/vacuum-deposited Mg. When Alq was deposited by IAD directly on PVCz, the luminance at a low drive voltage increased with increasing ion acceleration voltage up to 150 V. However, high ion acceleration caused a leakage current that does not contribute to luminescence, due probably to radiation damage in the PVCz/Alq junction. To avoid ion irradiation at the interface, Alq was deposited in two steps, in which the ion acceleration voltage was turned off in the first stage of deposition. The device characteristic was improved with the addition of this buffer layer. When the first two-thirds of the Alq layer was deposited without ion acceleration, luminescence efficiency was two fold higher than that in the case of no-acceleration deposition or vacuum deposition. The Alq layer formed by IAD had higher surface smoothness, which would contribute to the improvement of the Alq/Mg junction.
Structure of Trimer-Type Isocyanate Hardening Agents and Reactivity of Their Isocyanate Group
Authors: Kurihara Ken'ichi , Watanabe Haruo , Ata Masafumi , Kishii Noriyuki
Published: October 2002

The structure of a trimer-type isocyanate hardening agent was examined using laser desorption ionization time-of-flight mass spectra (LDITOF-MS) analysis and molecular orbital calculations. The conventional trimer-type agent of tolylene-2,4-diisocyanates (TDI) is confirmed to have higher multiples than three TDIs, and almost all these multiples consist of odd-numbered TDIs. Odd-numbered multiples are formed by the self-polymerization of TDIs, as an isocyanurate ring structure, which is more stable than the uretdione structure, is formed. The lower reactivity of the isocyanate groups of higher multiples is confirmed. This decreased reactivity of isocyanate groups as the number of multiples of TDIs increases is caused by the decrease in the atomic charge of carbon atoms in the isocyanate groups, which is attributable to the changing of the isocyanurate ring structure.
A Near-Field Scanning Optical Microscope Which Measures Both Constant-Height and Constant-Gap Images
Authors: Hatano Hiroshi , Inouye Yasushi , Kawata Satoshi
Published: October 2002

We have developed a near-field scanning optical microscope which has the
capability of imaging in both constant-height and constant-gap scanning
modes. This microscope uses an apertureless metallic probe. The
constant-gap position of the probe is controlled by regulation of the
tunneling-electron current. After obtaining a constant-gap signal under the
regulation at a pixel, the constant-height signal is measured at a probe
height, where is the same height at every pixel. By repeating the
measurement at each pixel, we got both constant-gap and constant-height
images. The result shows that the two imaging modes provide different
informations. The constant-gap image has higher contrast than the
constant-height one. Artifacts in near-field images measured by the
apertureless type microscope are also discussed.
Buried Optical Waveguides of Porous Silicon
Authors: Morio Takahashi Morio Takahashi , Minoru Araki Minoru Araki , Nobuyoshi Koshida Nobuyoshi Koshida
Published: October 2002

It is demonstrated that the refractive-index-controllable nature of luminescent porous silicon (PS) is directly applicable to the development of a three-dimensionally buried optical waveguide.
The PS waveguide is fabricated on a p-type silicon wafer by monolithic processes such as photolithography, ion implantation, anodization, and thermal oxidation.
An induced high contrast of refractive indices leads to efficient confinement and propagation of visible light.
When the active core layer is partially excited by a He-Cd (325 nm) laser, blue emission is observed from a cleaved facet.
The PS waveguide is potentially useful as a component of silicon-based photonic integration.
Improvement in Characteristics of Polycrystalline Silicon Thin-Film Transistors by Heating with High-Pressure H 2O Vapor
Authors: Toshiyuki Sameshima Toshiyuki Sameshima , Mitsuru Satoh Mitsuru Satoh , Keiji Sakamoto Keiji Sakamoto , Kentaro Ozaki Kentaro Ozaki , Keiko Saitoh Keiko Saitoh
Published: October 2002

A heat treatment with high-pressure H2O vapor at temperatures of 190 °C to 270 °C was applied to improve the characteristics of n-channel polycrystalline silicon thin-film transistors. The heating at 190 °C with 3.6×105 Pa H2O vapor increased the carrier mobility from 50 cm2V-1· s-1 (as fabricated) to 412 cm2V-1· s-1 and reduced the threshold voltage from 2.2 V to 1.1 V. The drain current at negative gate voltages caused by the heating with high-pressure H2O vapor was reduced by additional heating at 300 °C as well as at 350 °C with H2O vapor at one atmospheric pressure. This annealing process resulted in an on/off drain current ratio of 107.
Temperature Dependence of the Zero-Dispersion Wavelength of Dispersion-Shifted Fiber
Authors: Kim Sang Hyuck , Kim Dong Hwan , Jo Jae Cheol , Cho Kyu Man
Published: October 2002

We measured the temperature dependence of the zero-dispersion wavelength of dispersion-shifted fibers using a four-wave mixing process in the range of 22°C–59°C. From the experimental results, we found that the zero-dispersion wavelength increases linearly as the temperature around dispersion-shifted fiber(DSF) increases, and its slope is 0.032 nm/°C.
Short-Cavity Fabry-Perot Lasers Using Crystal Facets
Authors: Ando Seigo , Kobayashi Naoki , Ando Hiroaki
Published: October 2002

GaAs/AlGaAs short-cavity Fabry-Perot (F-P) lasers using vertical crystal facets as reflectors are fabricated by using selective area metalorganic vapor phase epitaxy (MOVPE). The laser structures consist of a (111)B growth plane and (110) sidewall facets vertical to the substrate surface. The sidewall facets are also crystallographically parallel to each other. These features are suitable for µm-size short-cavity F-P lasers. In addition, by using the lateral growth on the (110) facets in the selective area epitaxy, the edge of a GaAs active layer is covered with an AlGaAs layer to reduce the carrier loss caused by surface recombination. As a result, we successfully obtained a room-temperature lasing with a cavity length as short as 5 µm. This is the shortest cavity length in lateral F-P lasers that has so far been reported.
Development of One Period of a Three-Dimensional Photonic Crystal in the 5–10 µm Wavelength Region by Wafer Fusion and Laser Beam Diffraction Pattern Observation Techniques
Authors: Noritsugu Yamamoto Noritsugu Yamamoto , Susumu Noda Susumu Noda , Alongkarn Chutinan Alongkarn Chutinan
Published: October 2002

One period of
a three-dimensional photonic crystal operating
in the 5∼10-µm-wavelength region is developed,
where four layers
having a
striped pattern are stacked
using a wafer fusion
and
the alignment method based on
a laser beam diffraction pattern observation technique.
By measuring
the transmission spectrum, considerable attenuation
(of about 16 dB) is successfully achieved and
is in good agreement with the theoretical calculation.
Sequential Sputtering/Selenization Technique for the Growth of CuInSe2 Thin Films
Authors: Nakada Tokio , Kunioka Akio
Published: October 2002

We have proposed a sequential sputtering/selenization technique and apparatus for the growth of
CuInSe2 (CIS)-based thin films. The apparatus consists of a cylindrical rotating drum for holding
substrates and three horizontally interconnected subchambers for Cu, In, and Se fluxes. The serious
problem associated with hybrid sputtering of metal target contamination by Se flux has been greatly
reduced by the current geometric design. In this method, a very thin Cu/In stacked layer is first
sputter-deposited, and then selenized with thermally evaporated Se vapor at each rotation of the
drum. Polycrystalline CIS films for solar cells were grown by sequentially repeating these steps,
which prevented the formation of the micron-sized voids usually observed in CIS-based thin films
grown by selenization.
Low Temperature Copper to Copper Direct Bonding
Authors: Li Yang Albert , Bower Robert W. , Bencuya Izak
Published: October 2002

We have observed that it is possible to direct bond copper to copper
at low temperature. For sputtered Cu surface on silicon wafer without any further surface
planarization, we determined that 100°C temperature and uniform pressure (107 N/m2)
condition for three hours can produce a very strong Cu–Cu bond. A straight-pull test is
completed and the results revealed that an adhesion promoter layer is required at the
copper-silicon interface.
A Comparison of the Kinetics and the Evolution of Microstructure of the Solid Phase Crystallized a-(Si0.7Ge0.3/Si) and a-(Si/Si0.7Ge0.3) Bilayer Films; Interface versus Surface Nucleated Films
Authors: Kim Tae-Hoon , Ryu Myung-Kwan , Kim Ki-Bum
Published: October 2002

We have compared the kinetics and the evolution of microstructure of the solid phase crystallized a-(Si/Si0.7Ge0.3) and a-(Si0.7Ge0.3/Si) bilayer films deposited on SiO2 by low pressure chemical vapor deposition (LPCVD). It was identified that the overall thermal budget of the SPC, the grain size, and the evolution of microstructure were drastically different in these two samples. In particular, we have observed that the nucleation of an a-(Si/Si0.7Ge0.3) bilayer film started at the interface between the Si0.7Ge0.3 film and the SiO2 substrate while that of an a-(Si0.7Ge0.3/Si) started from the surface of the Si0.7Ge0.3 layer located at the surface. By changing the nucleation sites from interface to surface. the grain morphology was changed from elliptical to equiaxed and the grain size was enlarged from 0.3 µm to about 8 µm. However this resulted in an overall thermal budget increase.
A New Nonlinear Optical Borate Crystal K2Al2B2O7 (KAB)
Authors: Hu Zhang-Gui , Higashiyama Tetsuji , Yoshimura Masashi , Yap Yoke Khin , Mori Yusuke , Sasaki Takatomo
Published: October 2002

A new nonlinear optical (NLO) borate crystal K2Al2B2O7 (Potassium Aluminum Borate, KAB) has been discovered. The structure has been established by 4-axis X-ray diffraction methods. The material crystallizes in the trigonal space group P321 with a = 8.5657(9) Å, C = 8.463(2) Å and Z = 3. KAB possesses a space arrangement similar to Sr2Be2B2O7 (SBBO). A KAB crystal with a dimensions of 30×15×1 mm3 was grown using the Top-Seeded Solution Growth (TSSG) method. The optical properties of KAB were measured.
High Rate Deposition of Microcrystalline Silicon Using Conventional Plasma-Enhanced Chemical Vapor Deposition
Authors: Guo Lihui , Kondo Michio , Fukawa Makoto , Saitoh Kimihiko , Matsuda Akihisa
Published: October 2002

The deposition of hydrogenated microcrystalline silicon (µc-Si:H) at a relatively high working pressure is performed using a conventional radio-frequency plasma-enhanced chemical vapor deposition
method. Correlation of the deposition rate and crystallinity with deposition parameters, such as working pressure, flow rate, dilution ratio and input RF power, are
studied. It was found that the deposition rate exhibits a maximum at around 4 Torr and that the crystallinity of films decreases monotonically with increasing pressure.
The combination of SiH4 depletion and high working pressure in the plasma is necessary to improve the crystallinity of films deposited at a high rate. Consequently, a high deposition rate of 9.3 Å/s
is achieved with high crystallinity and low defect density.
Superconducting YBa2Cu3O7-δ-Ag Thin Films (TC( 0) = 90 K) by Pulsed Laser Deposition on Polycrystalline Ba2NdNbO6; A Novel Substrate for YBa2Cu3O7-δFilms
Authors: M. John Jose Kurian , K. Sajith Poo , Koshy Jacob , P. Pai Subash , Richard Pinto Richard Pinto
Published: October 2002

The development and characterisation of \ba, a novel ceramic substrate material for \yb superconductor, are reported. \ba has a complex cubic perovskite structure [\bb] with lattice constanta= 8.573Å. The dielectric properties of \ba are in a range suitable for its use as a substrate for microwave applications. \ba was found to have a thermal expansion coefficient of 8.6×10-6°C-1and a thermal conductivity of 87 W·m-1·K-1. Superconducting \yb-Ag thin films have been grownin situon polycrystalline \ba by pulsed laser ablation technique and the optimum conditions have been established. The films exhibited (00l) orientation of an orthorhombic \yb phase and gave a zero resistivity superconducting transition [TC(0)] at 90 K with a transition width of ∼1.5 K andJC∼3 ×105A/cm2at 77 K.
A New Structure of an N-Channel Junction Field-Effect Transistor Embedded in a Pin Diode for an X-Ray Detector
Authors: Hideharu Matsuura Hideharu Matsuura , Katsuhiko Nishida Katsuhiko Nishida
Published: October 2002

A new structure of an n-channel junction field-effect transistor (n-channel JFET) embedded in a pin diode for an X-ray detector is proposed. When a p/n junction, which is formed on the n- substrate (i. e., i layer) of the pin diode around the JFET, is reverse-biased, the depletion region is extended under the n channel of the JFET, because the donor density of the n- substrate is as low as 2 ×1012 cm-3. This indicates that the n channel can be electrically separated from the n- substrate, without a p region under the n channel. Since it is unnecessary to form the p region under the n channel, only one type of donor exists in the n channel of the JFET proposed here, suggesting that this n-channel JFET has the advantage of high performance due to high mobility and a low noise characteristic due to low defect densities.
Crystal Growth of Highly Oriented Zinc Oxide by Laser Deposition Technique with Metal-EDTA (ethylene diamine tetra-acetic acid) Complexes
Authors: Norio Tanaka Norio Tanaka , Shigeo Ohshio Shigeo Ohshio , Hidetoshi Saitoh Hidetoshi Saitoh , Keizo Uematsu Keizo Uematsu
Published: October 2002

Epitaxial ZnO films were grown by a new technique, complex beam epitaxy.
Highly oriented ZnO films grew at various substrate temperatures on (0001)
Al2O3 substrates with and without the existence of surface lattice
steps. The existence of the surface lattice steps had a strong effect on
the enhancement of the orientation degree.
The nonstepped substrate induced multinucleation growth of the crystals,
although crystals grew epitaxially on the alumina substrate.
In contrast, the stepped substrate promoted epitaxial lateral growth
and coalescence of the crystallites at relatively high substrate temperatures
ranging between 600 °C and 650 °C.
These crystals generated free exciton luminescence in the UV region
on 355 nm Nd:YAG laser irradiation.
Formation of Hydroxyapatite Thin Films on Surface-Modified Polytetrafluoroethylene Substrates
Authors: Shigeki Hontsu Shigeki Hontsu , Masaya Nakamori Masaya Nakamori , Nobuhiro Kato Nobuhiro Kato , Hitoshi Tabata Hitoshi Tabata , Junya Ishii Junya Ishii , Toshirou Matsumoto Toshirou Matsumoto , Tomoji Kawai Tomoji Kawai
Published: October 2002

An ArF excimer laser deposition technique is used to fabricate hydroxyapatite [Ca10(PO4)6(OH)2]-(HAp) thin films on surface-modified polytetrafluoroethylene (PTFE) substrates. The surface of PTFE is modified by a sodium-naphthalene complex in a glycol ether solvent. X-ray diffraction (XRD) studies indicate that as-deposited films prepared at substrate temperatures below the glass transition temperature of PTFE (327°C) are in an amorphous state. The crystallization of as-deposited films needed annealing for 10 h at 310°C.
The structure, surface morphology and bond strength of HAp films were evaluated using XRD, the atomic force microscopy (AFM) and the Instron testing machine. The tensile bond strength of HAp films on surface-modified PTFE was 6.0 MPa, which is one order of magnitude larger than that of films on non-surface-modified PTFE, demonstrating its potential for practical applications.
Analysis of Firing Voltage in a Plasma Display Panel of Coplanar Electrodes
Authors: Guangsup Cho Guangsup Cho , Young-Guon Kim Young-Guon Kim , Young-Sam Kim Young-Sam Kim , Dai-Geun Joh Dai-Geun Joh , Eun-Ha Choi Eun-Ha Choi
Published: October 2002

The analytical solution of Laplace's equation with a symmetric potential profile has been obtained
for investigating the breakdown criteria between the sustaining electrodes in the coplanar AC-type plasma
display panel. Using this solution, Paschen's Law has been analyzed along the various discharge paths
in the panel space using various sustaining electrode gap distances.
Role of Dislocation in InGaN Phase Separation
Authors: Sugahara Tomoya , Hao Maosheng , Wang Tao , Nakagawa Daisuke , Naoi Yoshiki , Nishino Katsusi , Sakai Shiro
Published: October 2002

The role of dislocation for luminescence in InGaN grown on sapphire substrate
by metal organic chemical vapor deposition (MOCVD) method was
investigated by cathodoluminescence (CL) and atomic force microscopy (AFM). The
CL emission area and dark spots between InGaN and GaN layers in InGaN/GaN single
quantum well (SQW) and multiple quantum well (MQW) structures showed completely
one to one correspondence. These results indicate that dislocations in InGaN work as
non-radiative recombination centers. Furthermore it was confirmed that the phase
separation in InGaN is caused by spiral growth due to mixed dislocations, and such a
growth mechanism is discussed.
Investigation of the Leakage Current in GaN P-N Junctions
Authors: Pernot Cyril , Hirano Akira , Amano Hiroshi , Akasaki Isamu
Published: October 2002

We report on the fabrication and evaluation of leakage current based on GaN p-n junctions
grown by metalorganic vapor phase epitaxy over sapphire. Si and Mg were used as n- and p-type
dopants, respectively. Reactive ion etching was used to define mesas of different sizes and metal
ohmic contacts were fabricated. Reverse dark current of 15 pA/mm2 was measured under -8 V bias
at room temperature, and that of 900 pA/mm2 was measured under -5 V bias at 480 K. Surface
leakage along the mesa sidewalls is suggested to be the main source of leakage under a low bias
voltage, and tunneling effects appear to be the main reason for junction breakdown.
Continuous-Wave Operation at 250 K of InGaN Multiple Quantum Well Laser Diodes Grown on 6H-SiC with Vertical Conducting Structure
Authors: Soejima Reiko , Kuramata Akito , Kubota Shin-ichi , Domen Kay , Horino Kazuhiko , Tanahashi Toshiyuki
Published: October 2002

We demonstrated continuous-wave operation at 250 K of InGaN multiple
quantum well laser diodes that were grown on 6H-SiC and had a vertical
conducting structure in which p-type and n-type electrodes were formed at
the top and the bottom of the chip, respectively. The threshold current,
threshold voltage, and threshold current density were 380 mA, 12.6 V, and
12 kA/cm2, respectively. The laser diodes were operated at room
temperature with a duty ratio up to about 20% at a repetition frequency of
1 kHz.
Intense Nickel-like Neodymium X-Ray Laser at 7.9 nm with a Double-Curved-Slab Target
Authors: Wang Shiji , Lin Zunqi , Gu Yuan , Huang Guanlong , Tang Huajing , Ximing Deng , Zhang Guoping , Daido YoshiakiKato , Imani Takeomi , Sezaki Shyuhei , Hirose Shingo , Yoon Geun-Young , Jitsuno Takahisa , Takagi Masaru , Mima Kunioki , Murai Kensuke , Takenaka Hisataka
Published: October 2002

We have demonstrated triple-pulse lasing combined with an X-ray mirror with 4 pumping pulses in
Ni-like Nd at 7.9 nm. Intense triple-pulse X-ray laser radiation has been generated with a double-curved-slab
target, which was irradiated with laser pulses of quasi-traveling wave configuration,
using cylindrical lens arrays for uniform pumping. An order of magnitude higher X-ray laser pulse
energy was observed along the forward-traveling wave direction compared to the backward-traveling
wave direction. Output energy in the forward direction was estimated to be ∼40 µJ.
THz-radiation Generation from an Intracavity Saturable Bragg Reflector in a Magnetic Field
Authors: Sarukura Nobuhiko , Ohtake Hideyuki , Liu Zhenlin , Itatani Taro , Sugaya Takeyoshi , Nakagawa Tadashi , Sugiyama Yoshinobu
Published: October 2002

We have demonstrated a new method to generate intense THz-radiation, up to a sub-microwatt level from a saturable Bragg reflector in a magnetic field. The saturable Bragg reflector is substituted in place of the end mirror in a femtosecond mode-locked Ti:sapphire laser pumped by an all-solid-state green laser.
New Semiconductor Alloy GaAs1-xBix Grown by Metal Organic Vapor Phase Epitaxy
Authors: Oe Kunishige , Okamoto Hiroshi
Published: October 2002

A new semiconductor alloy material, GaAs1-x
Bi
x
has been created by Metal Organic
Vapor Phase Epitaxial (MOVPE) growth. A low growth temperature, such as 365°C, is
required to obtain the alloy. X-ray diffraction measurements of alloy layers reveal that the
diffraction patterns are satisfactory. The maximum GaBi content in the GaAsBi alloy
estimated from the lattice constant is around 2%, which is consistent with that estimated from
secondary ion mass spectroscopy (SIMS) measurements. In a photoluminescence (PL)
measurement, a single peak spectrum is observed from 10 to 300 K. The temperature
variation of the PL peak energy is as small as 0.1 meV/K.
Properties of Full-Color Fluorescent Display Devices Excited by a UV Light-Emitting Diode
Authors: Yuichi Sato Yuichi Sato , Nobuyuki Takahashi Nobuyuki Takahashi , Susumu Sato Susumu Sato
Published: October 2002

Various inorganic and organic fluorescent films are excited using a newly developed ultraviolet light-emitting diode (UV-LED), and their optical properties are measured and discussed. The three pure primary colors are realized by the UV-LED irradiation and sufficient luminance for application to full-color displays in a room-lighting environment, is obtained. Film thickness dependence of the luminance is investigated, and UV irradiation on the frontside of the fluorescent films is preferred to realize high-efficiency devices.
A New Silicon Field-Effect Transistors with Two-Hole-Transport-Mode (HTM) Channels Grown by Molecular Beam Epitaxy (MBE)
Authors: Wu San Lein , Han Tzung Ting , Wang Yan Ping , Chang Shoou Jinn
Published: October 2002

In this paper, the two-hole-transport-mode (HTM) channels Si Metal Semiconductor
Field-Effect transistors (MESFET's) grown by molecular beam epitaxy (MBE) has been
developed. This device shows two peak steps in transconductance against the applied gate
voltage, which can be explained by means of the bandstructure. Extrinsic transconductances
of 50 mS/mm for the MODFET-Like HTM and 37.5 mS/mm for the δ-FET-like HTM were
obtained.
In(4×3) Reconstruction Mediated Heteroepitaxial Growth of InSb on Si(001) Substrate
Authors: Rao Bommisetty V. , Atoji Makoto , Li Don M. , Okamoto Tetsukazu , Tambo Toyokazu , Tatsuyama Chiei
Published: October 2002

In the present letter we report the epitaxial growth of 9000-Å-thick InSb on a Si(001) surface via In(4×3) reconstruction by
molecular beam epitaxy. The growth was monitored in situ using RHEED, Auger electron spectroscopy, scanning tunneling microscopy
and the exsitu characterization was done using X-ray diffraction, atomic force microscopy, and optical microscopy. The heteroepitaxy of
InSb on Si(001) surface is achieved despite the presence of a large lattice mismatch (over 19%) by incorporating a 0.5ML In(4×3)
reconstruction at the InSb/Si interface. Based on these results a model for the interface formation is developed.
Formation of a 100-µm-wide Stepfree GaAs (111)B Surface Obtained by Finite Area Metalorganic Vapor Phase Epitaxy
Authors: Nishida Toshio , Kobayashi Naoki
Published: October 2002

To perfectly flatten crystal facets, we propose a procedure that utilizes the balance between growth-material supply and desorption. By the suppression of two dimensional nucleation due to this desorption balance, stepfree facets can be obtained however large their area becomes, as long as their size is finite. We also confirm the validity of this assumption by obtaining a 100-µm-wide atomically stepfree surface on a GaAs (111)B substrate by using metalorganic vapor phase epitaxy.
Power-Limiting Action of Optical Waveguide Having Negative Nonlinear Claddings
Authors: Ohke Shigeaki , Umeda Tokuo , Cho Yoshio
Published: October 2002

In a three-layer slab optical waveguide with claddings having a negative nonlinear refractive
index, power-limiting action along the propagation direction is investigated numerically. Light
propagating behavior with power leak in the steady state propagation is demonstrated. Assuming
a close-to-available material and structural parameters, a short waveguide structure of this kind
is found capable of providing a sufficient power-limiting action.
High-Pulse-Energy, All-Solid-State, Ultraviolet Laser Oscillator Using Large Czochralski-Grown Ce:LiCAF Crystal
Authors: Liu Zhenlin , Izumida Shinji , Ohtake Hideyuki , Sarukura Nobuhiko , Shimamura Kiyoshi , Mujilatu Na , Baldochi Sonia L. , Fukuda Tsuguo
Published: October 2002

A large Ce3+:LiCaAlF6 (Ce:LiCAF) crystal of 15 mm diameter
was grown successfully by the Czochralski method. Owing to its large size, the
Ce:LiCAF crystal demonstrated a maximum output pulse energy from the
Ce:LiCAF laser of 21 mJ at a wavelength of 290 nm with an absorbed pump
energy of 54 mJ from the fourth harmonic of a Q-switched Nd:YAG laser
operated at a 10-Hz repetition rate. Furthermore, the lasing threshold was a
low 12 mJ, and the slope efficiency was 39%.
The Near-Field Super-Resolution Properties of an Antimony Thin Film
Authors: Tominaga Junji , Fuji Hiroshi , Sato Akira , Nakano Takashi , Fukaya Toshio , Atoda Nobufumi
Published: October 2002

A multilayered super-resolution near-field structure (Super-RENS) disk with the order of SiN/Sb/SiN/GeSbTe/SiN was produced on a
polycarbonate substrate. The readout resolution properties of small phase change marks recorded through an antimony thin film were
investigated. The linear and radial densities have been carefully examined, and it was found that the recorded phase change marks with
a size of 0.15 µm were mostly circle. Two different signal frequencies of 7.0 and 7.2 MHz were recorded on one land area between
grooves for tracking by offsetting the tracking to the right and left from the center. The width of the land area was 0.6 µm.
The recording linear velocity was 3.0 m/s. In the reading, both signals were detected at the center of the tracking. However, when the
tracking was offset at the positions of ±0.2 µm from the center, each signal was clearly separated without crosstalk owing to an Sb Super-RENS.
A Theoretical Model for Laser Cleaning of Microparticles in a Thin Liquid Layer
Authors: Lu Yong-Feng , Zhang Yong , Song Wen-Dong , Chan Daniel S. H.
Published: October 2002

A theoretical model for removal of tiny particles from solid surface by laser cleaning with a thin liquid layer is established by
taking adhesion force and cleaning force into account. When pulsed laser irradiates on the solid surface coated with a thin
liquid film, a sheet of liquid near the liquid/substrate interface can be superheated through thermal diffusion. The rapid growth
of vapor bubbles inside the superheated liquid can generate transient stress wave with high pressure, large enough to expel
micron and sub-micron particles from the contaminated surface. Through calculating adhesion force and cleaning force, the
cleaning threshold of laser fluence can be predicted from this theoretical model and the difference between cleaning force and
adhesion force increases with increasing of laser fluence, leading to higher cleaning efficiency.
Secondary Corrosion of Aluminum Alloy Due to Residual Sidewall and Its Removal Using M=0 Helicon Plasma Reactor
Authors: Kim Yun-Sang , Ji Ho-Yeon , Han Kyo-Sik , Song Chi-Wha
Published: October 2002

Various ways of the post metal etch treatment to prevent the possible secondary
corrosion was investigated. It is found that the one of the reasons of the degradation in
device wafer which processed by the post treatment after Al alloy(TiN/Al–Si–Cu/TiN/Ti)
plasma etch should be the potent corrosion occurred at the next device manufacturing
sequences. Usually it is hardly detected during normal inspections in dry process step.
BCl3 plasma treatment right after plasma etching could remove the precursor of the potent
corrosion by reducing Ti on the etched Al sidewall.
Initial Backbond Oxidation at an Unpaired Dangling Bond Site on a Hydrogen-Terminated Si(100)2×1 Surface
Authors: Kajiyama Hiroshi , Heike Seiji , Hitosugi Taro , Hashizume Tomihiro
Published: October 2002

The oxidation reaction at an unpaired dangling bond (DB) site on a hydrogen-terminated
Si(100)2×1 surface was studied using an ultrahigh-vacuum scanning tunneling
microscope. The surface image was observed in situ during the exposure to O2
molecules at room temperature. During exposure, the unpaired DBs induced structural
changes around themselves, and they were mostly localized on one side of a Si dimer
bond. We conclude that the backbonds near an unpaired DB were preferentially
oxidized, following the dissociation of O2 molecules at the unpaired DB site. Based on
high-resolution measurements, models of backbond-oxidized-structure were proposed.
Raman Scattering of InAs1-x-ySbxPy Quaternary Alloys
Authors: Chen Lung-Chien , Tyan Shing-Long , Wu Meng-Chyi
Published: October 2002

The Raman scattering of InAs1-x-y
Sb
x
P
y
quaternary alloys grown on (100)InAs
substrates by liquid-phase epitaxy is studied in this work. The peaks at 182,
216, 234 and 312 cm-1 in the Raman spectra are assigned as the InSb LO, InAs TO,
InAs 1LO and InP LO modes, respectively. The mode of 476 cm-1 is assigned
as the
second-order Raman mode, InAs 2LO Raman mode. Also, both the 228- and 303-cm-1 lines are
attributed to the disorder-activated optical phonons. In addition, the Raman
scattering spectra in InAs1-x-y
Sb
x
P
y
quaternary alloys exhibit a three-mode behavior.
Biaxially Textured YBa2Cu3O7-δ Conductors on Rolling Assisted Biaxially Textured Substrates with Critical Current Densities of 2–3 mA/cm2
Authors: Mathis John E. , Goyal Amit , Lee Dominic F. , List Fred A. , Paranthaman M. , Christen David K. , Specht Eliot D. , Kroeger Donald M. , Martin Patrick M.
Published: October 2002

Epitaxial YBa2Cu3O7-δ (YBCO) films with transport critical current densities
approaching 3×106 A/cm2 (77 K, 0 T) were fabricated using laser ablation of
YBCO onto rolling-assisted biaxially
textured-substrates (RABiTS) using a
combination of thin CeO2 and thick YSZ buffer layers. The configuration of the
sample was YBCO (∼0.2 µm)/YSZ (0.7 µm)/CeO2 (0.05 µm)/Ni (125 µm). The
CeO2 and YSZ buffer layers were deposited using electron-beam evaporation and
sputtering, respectively. The temperature window for successful pulsed-laser
deposition of YBCO onto RABiTS was found to be between 740°C and 790°C.
Observation of Isotope Shift in Autoionization Levels of Uranium Atom
Authors: Ogura Koichi , Shibata Takemasa
Published: October 2002

235U was ionized with high selectivity by two-wavelength two-step resonance photoionization. The autoionization level of this
scheme has a large isotope shift of 0.51 cm-1 and a narrow spectral linewidth of 0.08 cm-1. It was found that this high selectivity
for 235U ionization is due to not only an isotope shift of the intermediate level but also the large isotope shift and the narrow
linewidth of the autoionization level. The lifetime of the intermediate level of this ionization scheme, 23197.009 cm-1, was measured
by the delayed coincidence method and was found to be 215 ns.
Analysis of Barber-Pole Color and Speckle Noises Recorded 6 and a Half Hours before the Kobe Earthquake
Authors: Hiroshi Matsumoto Hiroshi Matsumoto , Motoji Ikeya Motoji Ikeya , Chihiro Yamanaka Chihiro Yamanaka
Published: October 2002

Barber-pole color shift and speckle noise in the images on the
videotape of a TV program recorded six and a half hours before the Kobe
earthquake have
been analyzed and are considered to be due to electromagnetic (EM)
noise of a few tens of mV/m
around 217 MHz and pulsed noise with a width of about µs,
respectively. Such images were reproduced by artificial means using a
microwave synthesizer and from air-gap discharges using a Van de
Graaff generator. An EM model of a fault with piezo-compensating free
charges around quartz in granitic rocks gave pulsed EM waves having a
pulse width of 0.5 µs and height of 0.5 V/m at a point 50 km
from the fault.
Formation of Silicon-Gold Eutectic Bond Using Localized Heating Method
Authors: Liwei Lin Liwei Lin , Yu-Ting Cheng Yu-Ting Cheng , Khalil Najafi Khalil Najafi
Published: October 2002

A new bonding technique is proposed by using localized heating to supply
the bonding energy.
Heating is achieved by applying a dc current through micromachined heaters
made of gold which serves as both the heating and bonding material.
At the interface of silicon and gold, the formation of eutectic
bond takes place in about 5 minutes.
Assembly of two substrates in microfabrication processes
can be achieved by using this method.
In this paper the following important results are obtained:
1) Gold diffuses into silicon to form a strong eutectic bond by
means of localized heating.
2) The bonding strength reaches the fracture toughness of the bulk silicon.
3) This bonding technique greatly simplifies device fabrication and
assembly processes.
Sub-Nanometer Scale Measurements of Silicon Oxide Thickness by Spectroscopic Ellipsometry
Authors: Gonda Satoshi , Tanaka Mitsuru , Kurosawa Tomizo , Kojima Isao
Published: October 2002

Possibility and limitation of sub-nanometer thickness measurements with spectroscopic
ellipsometry (SE) of ultrathin silicon oxide on hydrogen-terminated silicon were investigated,
in comparison with X-ray photoelectron spectroscopic (XPS) measurements of the same
sample. Experimental results obtained from SE showed ultraslow growth of the oxide with
the increase of time in air t (hours) at the rate of 0.7·log
10
t (nm) up to 100 hours. During the
hydrogen termination prevented from the oxidation for 4 hours by XPS observation, the
`oxide thickness' remained at 0.3 nm at the initial stage of the oxidation by SE measurements.
A Complex Heterostructure to Achieve a Single-Crystalline MgO Film on GaAs (001)
Authors: Saiki Koichiro , Nishita Kouichi , Koma Atsushi
Published: October 2002

A single-crystalline MgO film was grown on GaAs(001) by constructing a complex heterostructure with two alkali halide buffer layers.
The growth temperature was decreased to 150°C as compared with direct growth of MgO on GaAs(001). Electron energy loss spectrum of the grown film agreed well with that of bulk
MgO, indicating that surface stoichiometry was maintained. The structure was stable up to 600°C against heating in UHV condition. The concept of a complex heterostructure
will help fabrication of functional oxide layers on GaAs substrates and lead to oxide/semiconductor integrated devices.
Three-Valued Single-Electron Memory Array with Reading Circuits
Authors: Kouichirou Yamamura Kouichirou Yamamura , Yoshiyuki Suda Yoshiyuki Suda
Published: October 2002

We first demonstrate a method of realizing a multiple-valued single-electron memory device based on Monte Carlo simulation results. Using the simulation method, we demonstrate that with a memory array constructed with memory cells, each of which has a junction-capacitor-junction single-electron memory device and a reading circuit, three logical values “-1", “0", and “1" can be written, held and read, and that the memory array successfully functions as a three-valued memory array. Since the results of a logical summation of input and stored data can be stored in the cell, the memory array functions as a novel functional memory.
GaInAsP/InP Multiple Short Cavity Laser with λ/4-Air Gap/Semiconductor Bragg Reflectors
Authors: Madhan Raj Mothi , Kazunori Numata Kazunori Numata , Shunsuke Toyoshima Shunsuke Toyoshima , Shigehisa Arai Shigehisa Arai
Published: October 2002

A room temperature operation of multiple cavity (MC) laser consisting of λ/4-air gap (=0.39 µm) and semiconductor reflectors was fabricated using two steps organometallic vapour-phase epitaxy (OMVPE) and two steps wet chemical etching. The threshold current as low as 78 mA (J
th = 1.25 kA/cm2) was obtained for a total cavity length 164 µm (Pitch Λ: 20 µm; 8 elements) and stripe width of 40 µm. The effective power reflectivity of this cavity structure was estimated to be higher than 92%.
Simulation of Mode Selectability Characteristics by Phase Constraint in a Bare Coordinate-Transforming Cavity
Authors: Nemoto Koshichi , Oishi Yuji , Fukuchi Tetsuo , Goto Naohiko , Fujii Takashi
Published: October 2002

We show that the coordinate-transformed mode, which is the transformation from a Gaussian
profile to a uniform circular one, is selected through iteration of round trips in a bare cavity, using
Fox-Li simulation. When the phase constraint due to cavity mirrors is dominant, the intensity profiles
converge to the desired profiles.
Phase Matching Effects in a Traveling-Wave Photodetector by Multibeam Excitation
Authors: F. Taylor Bong-Sin Kwark
Published: October 2002

In this letter, phase matching effects are investigated in a
traveling-wave photodetector on semi-insulating GaAs substrate, which
has coplanar strips(CPS) electrode and photoconductive active area. With
the phase-matched four-beam excitation, power gain of about 11 dB can be
obtained compared to that of single excitation in this structure. Phase
mismatching patterns of the output power for the device are demonstrated
and compared with theoretical data.
Location Control of Crystal Si Grain Followed by Excimer-Laser Melting of Si Thin-Films
Authors: Wilt Ryoichi Ishihara
Published: October 2002

We propose a new method to control the position of a crystal silicon grain following excimer-laser melting of a thin silicon (Si) film. The thickness of the thermal isolation layer underlying the Si film was locally decreased in order to make the temperature of molten-Si at a predetermined point lowest so as to initiate the nucleation preferentially from the position. A crystal silicon grain with a diameter of 1.2 µm was located exactly at the predetermined position.
Digital Etching of (001) InP Substrate by Intermittent Injection of Tertiarybutylphosphine in Ultrahigh Vacuum
Authors: Otsuka Nobuyuki , Oyama Yutaka , Kikuchi Hideyuki , Nishizawa Jun-ichi , Suto Ken
Published: October 2002

The intermittent injection of tertiarybutylphosphine (TBP), the injection and the evacuation
of which are cyclically repeated, has been used for the selective-area etching of an InP (001)
surface to study the surface adsorption/desorption mechanism in ultrahigh vacuum. Digital
etching is achieved, as described by a modified Langmuir-type equation. It is assumed that TBP
adheres to the surface within 0.1 s even at an injection pressure of 3×10-5 Torr and prevents
phosphorus dissociation during evacuation times longer than 5 s. The activation energy of
18 kcal/mol (at 340–390°C) is lower than that using tris-dimethylaminophosphorus. A specular
surface is obtained on a sulfur-doped substrate.
Epitaxial Growth of Ti1- xAl xN Buffer Layer for a Ferroelectric (Ba, Sr)TiO3 Capacitor on Si Substrate
Authors: Yanase Naoko , Sano Kenya , Abe Kazuhide , Kawakubo Takashi
Published: October 2002

Epitaxial titanium aluminum nitride, Ti1-x
Al
x
N(100) (0≦x<0.5), was grown on Si(100) substrates at 600°C by low-energy reactive ion beam deposition using N2
+ ion beam irradiation with 100 eV energy and Ti and Al simultaneous evaporation. The epitaxial relationship was confirmed to be Ti1-x
Al
x
N(100)//Si(100), Ti1-x
Al
x
N<110>//Si<110> by X-ray diffraction (XRD) and in situ reflection high-energy electron diffraction (RHEED). Although the electrical resistivity increased exponentially with x, the values remained on the order of 10-4 Ω·cm. Using the Ti1-x
Al
x
N buffer layer, we have successfully fabricated a capacitor with an epitaxial (Ba, Sr)TiO3 film on a Si substrate.