bluuebunny/crossref_metadata_2025 huggingface dataset:
Photopolymerization Induced by Optical Field Enhancement in the Vicinity of a Conducting Tip under Laser Illumination
Authors: Chrystelle Triger Grégory Wurtz , Carole Ecoffet Carole Ecoffet , Daniel-Joseph Lougnot Daniel-Joseph Lougnot
Published: October 2002

We introduce a method of local photopolymerization in the
submicrometer scale. The
source used is a metallic tip whose extremity presents a strong localized optical
near-field enhancement (FE) when the tip is illuminated by a laser beam suitably
polarized. The FE permits the polymerization threshold dose to be locally exceeded at the
tip extremity while the threshold is not reached elsewhere. By this method
the formation
of micronic/nanometric polymer dots has been demonstrated. The preliminary
results presented here validate experimentally the concept of the local optical
source issued from a conducting tip.
Picosecond Time-Resolved X-Ray Diffraction from Si(111) under High-Power Laser Irradiation
Authors: Hironaka Yoichiro , Yazaki Akio , Saito Fumikazu , Nakamura Kazutaka G. , Kondo Ken-ichi
Published: October 2002

Picosecond time-resolved X-ray diffraction is used to observe Si(111) under 300 ps pulsed laser irradiation at a power density above the damage threshold. The pulsed X-rays (of about 9 ps pulse width) are generated by focusing a femtosecond laser on an Fe target. The rocking curves are obtained with a time step of 50 ps. The transient lattice compression (0.9% at maximum) driven by laser-induced dielectric breakdown is directly observed.
Investigation of Fatigue Mechanisms in Pb(Zr, Ti)O3 Films from a Correlated Analysis of Hysteresis Parameters in a Lattice Model with Distributed Polarization Clamping
Authors: Ricinschi Dan , Lerescu Alexandru Ionut , Okuyama Masanori
Published: October 2002

Several hypotheses concerning possible fatigue mechanisms have been implemented in the Landau theory-based lattice model for switching, and their suitability for explaining the fatigue of Pb(Zr, Ti)O3 films has been examined. A correlated analysis of the fatigue behavior of the hysteresis loop parameters has been shown to offer precise criteria for validating the fatigue scenarios and disclose the polarization state of fatigued ferroelectrics. The spatial distribution of bipolar clamping of polarization by a built-in electric field, in randomly spreading weak ferroelectricity regions, reflected with best accuracy the fatigue experimental data.
Generation of Pretilt Angle for Nematic Liquid Crystal Using an In Situ Photoalignment Method on Polymer Surfaces
Authors: Seo Dae-Shik , Kim Hyung-Kyu
Published: October 2002

Generation of pretilt angles in a nematic liquid crystal (NLC) using an in situ photoalignment method with polarized UV exposure during imidization of polyimide (PI) on two kinds of PI surfaces with side chains was investigated. The pretilt angles of NLC generated using the in situ photoalignment method were smaller than those generated using a conventional photoalignment method for a short UV exposure time. Also, the pretilt angles of NLC generated using the in situ photoalignment method increase with increasing UV exposure time on PI surfaces. Finally, the pretilt angles of NLC can be improved by annealing.
High Degree of Dissociation of Nitrogen Molecules in Large-Volume Electron-Beam-Excited Plasma
Authors: Kazunari Taniguchi Kazunari Taniguchi , Masaya Sugimoto Masaya Sugimoto , Shingo Masuko Shingo Masuko , Toshihiro Kobayashi Toshihiro Kobayashi , Manabu Hamagaki Manabu Hamagaki , Petros Abraha Petros Abraha , Tamio Hara Tamio Hara
Published: October 2002

The degree of dissociation of nitrogen is measured in a large-volume N2-Ar mixture plasma generated by an electron-beam-excited plasma device. The device features independent control of the beam current and energy. In setting the beam current and energy at 3.4 A and 140 V, the degree of dissociation of nitrogen was 0.16. The high degree of dissociation is attributed to the characteristics of the system in which the degree depends on the beam energy fed into the plasma and not the size of the chamber, as it is in conventional plasma sources. In view of the device characteristics, high-density atomic nitrogen can be obtained with electron-beam-excited plasma in a large-volume device.
Random Telegraphic Signals and Low-Frequency Noise in Rapid-Thermal-Annealed Silicon-Silicon Oxide Structures
Authors: Chim Wai Kin , Leong Kok Keong , Choi Wee Kiong
Published: October 2002

Random telegraphic signals (RTSs) were observed in aluminium-silicon oxide-silicon (Al–SiO2–Si) metal-oxide- semiconductor capacitors with large contact areas of about 7.85×10-3 cm2, which have been subjected to rapid thermal annealing (RTA) in an argon ambient at 600 to 700°C for 50 s. The RTSs change from a two-level RTS to a multilevel RTS as the device bias voltage or temperature is increased. Samples showing RTSs generally exhibit low breakdown voltages and show a Lorentzian spectrum at a frequency between 30 to 400 Hz. Furthermore, the interface-state density from samples exhibiting RTSs is generally higher than that from samples that do not show any RTSs. We suggest that the RTA process over a specific temperature range has produced weak spots in the devices. The filling and emptying processes of a trap near a weak spot modulate the barrier height, resulting in the RTS and the Lorentzian spectrum observed in these devices.
Steady State of Dense Sheet Z-Pinch with Thermal Conduction
Authors: Alexander Muravich Alexander Muravich , Tetsu Miyamoto Tetsu Miyamoto , Victor Vikhrev Victor Vikhrev
Published: October 2002

The problem of steady state of the sheet Z-pinch was solved, incorporating the thermal conductivity effects. In particular, solutions which incorporate low plasma pressure and low temperature on the sheet boundary are investigated. Three types of temperature profiles were identified. Dependence of the solution type on the pinch plasma parameters was determined.
High-Energy-Density Plasma Produced by Pulsed High Current Discharge of Powder
Authors: Hidenobu Nozawa Hidenobu Nozawa , Hidetoshi Ishihara Hidetoshi Ishihara , Yoshihiro Kawasaki Yoshihiro Kawasaki , Jun Kuroda Jun Kuroda , Shinji Ibuka Shinji Ibuka , Yuan-Shing Liu Yuan-Shing Liu , Koichi Yasuoka Koichi Yasuoka , Shozo Ishii Shozo Ishii
Published: October 2002

A plasma created from copper powder was successfully obtained under pulsed high current discharges. Powder flow was injected transiently between the electrodes in vacuum or those in the air. The powder particles are spherical and are accelerated by pulsed electrostatic fields. Diverging powder flow was controlled to form a directed flow with a constant diameter by applying an extra focusing electrode. The powder particle trajectories were numerically analyzed to design the focusing electrode structure. Conical light emission from the particles was observed in framing photographs during the early stage of the discharges.
Characteristics of Ion Beams Produced in a Plasma Focus Device
Authors: Takao Kazuto , Doi Yasuhiko , Hirata Satoshi , Shiotani Masaki , Kitamura Iwao , Takahashi Takakazu , Masugata Katsumi
Published: October 2002

The characteristics of the ion beams produced in a plasma focus device were studied. In the experiment, a Mather-type plasma focus device was used which was prefilled with H2 at 2.3 Torr. Ion species and their energy spectra were evaluated with a Thomson parabola spectrometer. The particle pinhole image was obtained with an aluminum filtered particle pinhole camera. The ion current density was measured with a biased ion collector. From the measurement, the proton beam energy was found to be distributed from 0.15 MeV to 2 MeV. The particle pinhole image of the proton beam with an energy of more than 1 MeV has spotlike patterns. The ion current density of 2400 A/cm2 with a pulse width of 50 ns was observed on the axis at z=260 mm from the top of the anode. The peak power brightness of the proton beams was evaluated to be 18 GW/cm2/sr/keV, and the total power brightness was evaluated to be 20 TW/cm2/sr.
Preparation of B4C Thin Film by Intense Pulsed Ion-Beam Evaporation
Authors: Kitajima Kazuo , Suzuki Tsuneo , Jiang Weihua , Yatsui Kiyoshi
Published: October 2002

Boron carbide (B4C) is known as a material having hardness, wear resistance and stability at high temperature. The preparation of thin films of B4C, therefore, is very important from the viewpoint of industrial applications. We have experimentally attempted to prepare thin films of B4C using the pulsed ion-beam evaporation (IBE) technique, where high-density ablation plasma is produced by an intense pulsed ion beam interaction with the target. The crystallized B4C thin films have been successfully deposited on a Si (100) substrate by front-side and mask-side deposition. Absorptions associated with the B–C combination and the vibration of B12–B12 clusters have been observed by Fourier transform infrared spectroscopy. The Vickers hardness of the film deposited by front-side deposition is observed to be HV∼2300.
Preparation of SrAl2O4:Eu Phosphor Thin Films by Intense Pulsed Ion-Beam Evaporation
Authors: Sengiku Michinori , Oda Yoshikane , Jiang Weihua , Yatsui Kiyoshi , Ogura Yukihiro , Kato Keizo , Shinbo Kazunari , Kaneko Futao
Published: October 2002

SrAl2O4 activated with Eu phosphors has been known to exhibit high brightness and long-lasting phosphorescence without radioactive materials. In this paper, SrAl2O4:Eu thin films have been successfully deposited on Si(100) or graphite substrates using an intense pulsed ion-beam evaporation technique. The results of X-ray diffraction and photoluminescence suggest that SrAl2O4:Eu thin films which have a polycrystalline structure can be produced in vacuum, without substrate heating and annealing. The composition and morphology of the films have been analyzed by Rutherford backscattering spectroscopy (RBS) and scanning electron microscopy (SEM). From RBS analysis, we have obtained good stoichiometry between the target and the films prepared.
Luminescent Properties of SrAl2O4:Eu Thin Films Deposited by Intense Pulsed Ion-Beam Evaporation
Authors: Kato Keizo , Ogura Yukihiro , Sengiku Michinori , Shinbo Kazunari , Kaneko Futao , Oda Yoshikane , Yatsui Kiyoshi
Published: October 2002

SrAl2O4 activated with Eu, a long-phosphorescence material with high brightness, has been successfully deposited on Si substrates using intense pulsed ion-beam evaporation. Efficient preparation of long-phosphorescence thin films has been achieved using a high-density ablation plasma produced by the interaction of an intense pulsed ion-beam with the SrAl2O4:Eu target. The prepared SrAl2O4:Eu thin films had a polycrystalline structure without annealing and showed a typical photoluminescence of SrAl2O4:Eu at around 520 nm. Thermoluminescence (TL) measurements were carried out in order to obtain the lifetimes of the phosphorescence. In particular, TL spectra in the higher temperature region, which contributed to the long phosphorescence, were examined by the partial heating technique to evaluate the distributed trap depths and the lifetimes. The phosphorescence lifetime at 300 K for the prepared film was found to be about 180 min.
Synthesis of Ti–Al Intermetallic Compound Films by Intense Pulsed Ion Beam Evaporation
Authors: Suzuki Tsuneo , Kishima Masayuki , Jiang Weihua , Yatsui Kiyoshi
Published: October 2002

In order to examine the possibility of the synthesis of an intermetallic compound thin film by intense, pulsed, ion beam evaporation (IBE), the synthesis of thin films of Ti–Al system intermetallic compound was attempted. The crystal structure and composition of the films were evaluated. By using a combination target of Ti and Al, thin films of single phase could not be synthesized, while the Ti3Al film was found to be successfully synthesized by using a Ti/Al sintered target. The Ti3Al film was orientated in the 002 plane.
Preparation and Characterization of C–N–H–O Thin Film by Ion Beam Evaporation
Authors: Suzuki Tsuneo , Shioiri Kenji , Jiang Weihua , Yatsui Kiyoshi
Published: October 2002

The preparation of a C–N–H–O thin film has been attempted by an ion-beam evaporation method. Although distinct X-ray diffraction lines were not observed, C≡N bond formation was observed to be enhanced by substrate heating by means of Fourier transformation infrared spectroscopy (FT-IR). The hydrogen/carbon concentration ratio decreases and the nitrogen/carbon concentration ratio increases with increasing substrate temperature, as measured by Rutherford backscattering spectroscopy (RBS) and elastic recoil detection analysis (ERDA). The hardness of the thin film prepared was found to be 1 GPa.
Characteristics of CrN Films Prepared by Pulsed Laser Deposition
Authors: Hirai Makoto , Ueno Yasuhiro , Suzuki Tsuneo , Jiang Weihua , Grigoriu Constantin , Yatsui Kiyoshi
Published: October 2002

Chromium nitride (CrN) films have been successfully prepared by pulsed laser deposition (PLD). An experiment was carried out by changing the substrate temperature from RT to 600°C. The hardness of the films increased gradually with an increase in the substrate temperature up to 400°C, above which it decreased rapidly. Furthermore, the maximum Vickers hardness (HV) value was ∼2000. The rapid decrease in the hardness was induced by the formation of ellipsoidal grains. The boundaries of these grains appear to have structural defects. As a result of an oxidation test, it was confirmed by Fourier transform infrared spectroscopy (FTIR) that the CrN film is oxidized at a temperature close to 600°C. At this temperature, some cracks appear which is considered to be due to the volume expansion induced by oxidation.
Characteristics of (Cr1-x, Alx)N Films Prepared by Pulsed Laser Deposition
Authors: Hirai Makoto , Ueno Yasuhiro , Suzuki Tsuneo , Jiang Weihua , Grigoriu Constantin , Yatsui Kiyoshi
Published: October 2002

Chromium aluminum nitride ((Cr1-x
, Al
x
)N) films have been successfully prepared by pulsed laser deposition (PLD). Experiments were carried out by changing the surface area ratio of the target (Al/(Cr+Al)) from 0 to 100%. From the results of energy-dispersive X-ray spectroscopy (EDS) and Rutherford backscattering spectroscopy (RBS), we have found that the metal content ratio of the film agreed well with the surface area ratio of the target. The hardness of the (Cr1-x
, Al
x
)N films showed the maximum value (HV∼3000) at x=0.75. Phase transition from the B1 (NaCl) structure to the B4 (würtzite) structure occurred above x=0.75, which was in reasonable agreement with the theoretical prediction. The result of the oxidation test revealed that the CrN film was oxidized at approximately 600°C, whereas in the (Cr0.5, Al0.5)N film, the existence of oxide was not detected in the annealing temperature range of RT to 900°C.
Preparation of Oxygenated Fullerene Thin Film for Photoelectric Devices
Authors: Sung-Chae Yang Sung-Chae Yang , Tetsu Mieno Tetsu Mieno
Published: October 2002

In order to obtain a higher photocurrent in metal/insulator/semiconductor junction cells, oxygenated fullerene thin films are used as a insulator thin films. Highly oxygenated fullerene thin films are obtained using RF O2 plasma with a cooling system. The experimental results revealed that oxygenated fullerene thin films, C60Ox (x=8, 16, 24, 38, 50 etc.), are obtained using a laser-desorption time-of-flight mass spectrometer (TOF-MS). By using the 200 nm an thick multilayer fullerene junction film, the photocurrent becomes 30 times larger than that of a normal fullerene.
Nanosize Al2O3 Powder Production by Pulsed Wire Discharge
Authors: Suzuki Tsuneo , Keawchai Komson , Jiang Weihua , Yatsui Kiyoshi
Published: October 2002

Nanosize Al2O3 powder was produced by pulsed wire discharge. The discharge was carried out at a peak current of ∼10 kA, the pulse length of ∼20 µs, and pulse energy of ∼80 J. Nanosize γ-Al2O3 powders have been synthesized by pulsed discharge of metal wires in oxygen as an ambient gas. The powder size and its distribution were controlled by the oxygen pressure.
Numerical Simulation of Carbon Simple Cubic by Dynamic Compression
Authors: Kaori Kato Kaori Kato , Takayuki Aoki Takayuki Aoki , Toshimori Sekine Toshimori Sekine
Published: October 2002

An impact scheme of a slab target and flyer with a layered structure is proposed to achieve low-entropy dynamic compression of diamond. The thermodynamic state of diamond during compression is examined using one-dimensional Lagrangian hydrodynamic code and the tabulated equation of state library, SESAME. The use of a material with a small shock impedance for the impact interfaces markedly decreases the strength of the primary shock wave. It is found that a gradient of shock impedance across the thickness of the flyer generates small multiple shock waves into the diamond and is effective for low-entropy compression. The thermodynamic conditions required for carbon simple cubic and low-entropy dynamic compression is achieved.
In situ Annealing of GaInNAs up to 600°C
Authors: Kondow Masahiko , Kitatani Takeshi
Published: October 2002

We have found that the optimum annealing temperature for GaInNAs depends on the crystallinity of the as-grown crystal, and that GaInNAs with superior crystallinity grown by solid-source molecular beam epitaxy can survive at 600°C during a considerably long annealing process.
Internal Electric Field Formation in Insulators under High-Flux Negative-Ion Implantation
Authors: Amekura Hiroshi , Plaksin Oleg A. , Kishimoto Naoki
Published: October 2002

Ion-flux-dependent nanoparticle formation is observed in silica glasses during high-flux 60 keV Cu- implantation. Under the high-flux implantation, a strong electric field possibly forms in the glasses, and may affect the nanoparticle formation via the solute diffusion processes. In this study, the internal-field formation is evaluated based on a model of negative-ion implantation, in which the difference in diffusion lengths between electrons and holes induces field formation. The calculated fields remain at more than 2000 nm in depth, although the ion range is ∼45 nm. The fields depend negligibly on the ion flux and the maximum value is 3.3 kV/cm. A mechanism for creating the internal field and the possibility of high-flux effects are discussed.
Flue Gas Treatment by Intense Pulsed Relativistic Electron Beam
Authors: Ikegaki Takuro , Seino Satoshi , Oda Yasuyuki , Matsuda Takuya , Imada Go , Jiang Weihua , Yatsui Kiyoshi
Published: October 2002

Removal of NO
X
has been studied using an intense pulsed relativistic electron beam (IREB). The chamber is 20 cm long, and is irradiated by the IREB of 2 MV or 8 MV with the pulse width of 50 ns (full width at half maximum: FWHM). With the initial NO concentration of 100 ppm and pressure of 120 kPa, ∼50% of NO is removed by firing of 10 shots of IREB, yielding 5 ppm/shot. The NO
X
removal amount in one shot does not depend on the initial NO concentration and electron energy.
Analysis of the Pulsed Plasma Reactor Impedance For DeSOx and DeNOx
Authors: Choi Young Wook , Lee Hong Sik , Rim Geun Hie , Kim Tae Hee , Jang Gil Hong , Shin Wan Ho , Song Young Hoon
Published: October 2002

In this study, the impedance characteristics of the wire-plate pulsed plasma reactor for deSO
x
and deNO
x
were investigated. The experiments were carried out with a small size reactor (15 Nm3/h) and a prototype reactor (2000 Nm3/h, 0.5 MW) using a rotary spark gap switch and magnetic pulse compression (MPC) modulator, respectively. The impedance characteristics of the reactor were mainly varied by varying the charge voltage, wire length and wire-plate distance. With increasing charge voltage and wire length, the reactor impedance was decreased. From these experiments, the best condition for the impedance matching between the pulse generator and the reactor was achieved. In addition, we performed an analysis of the nonlinear reactor impedance on the basis of results of the experiment and electromagnetic transients program (EMTP) study. From these, we found that even though the electric equivalent circuit of the reactor may be described by a nonlinear resistance in parallel with a varying capacitance, the reactor impedance could be approximately analyzed using the equivalent resistance value of the flat zone and the reactor's initial capacitance.
Side-Extraction-Type Secondary Emission Electron Gun Using Wire Ion Plasma Source
Authors: Chalise Priya Raj , Ishikawa Masaki , Watanabe Masato , Okino Akitoshi , Ko Kwang-Cheol , Hotta Eiki
Published: October 2002

A secondary emission electron gun applicable for gas treatment was designed, fabricated and tested. The gun is set beside an ion source, which is called a wire ion plasma source (WIPS). Ions extracted from WIPS are accelerated toward the cathode surface, which is set oblique to the ion loci. Secondary electrons emitted from this cathode surface by the collision of ions are then accelerated toward the electron window and form a very wide electron beam. The electron window is set orthogonal to the ion extraction window and has earth potential. In order to inject the electron beam perpendicular to the electron window, the ion and electron trajectories were numerically simulated for several conditions. A wide electron-beam current distribution was observed inside the gas treatment chamber when a honeycomb board and an Al film were placed at the electron window. The electron-beam current density of 6.4 mA/cm2 measured at the cathode voltage of 80 kV possesses sufficient energy to irradiate gaseous pollutants such as NO
x
.
Extraction of Trap States at the Oxide-Silicon Interface and Grain Boundary in Polycrystalline Silicon Thin-Film Transistors
Authors: Kimura Mutsumi , Nozawa Ryoichi , Inoue Satoshi , Shimoda Tatsuya , Lui Basil On-Kit , Tam Simon Wing-Bun , Migliorato Piero
Published: October 2002

A technique to extract trap states at the oxide-silicon interface and grain boundary has been developed for polycrystalline silicon thin-film transistors with large grains. From the capacitance–voltage characteristic, the interface traps can be extracted. The potential and carrier density are also extracted. From the potential, carrier density and current–voltage characteristic, the boundary traps can be extracted by considering the potential barrier at the grain boundary. Using a two-dimensional device simulation, the adequacy of this extraction technique was confirmed.
Radioactive Reliability of Programmable Memories
Authors: Loncar Boris , Osmokrovic Predrag , Stojanovic Marko , Stankovic Srboljub
Published: October 2002

In this study, we examine the reliability of erasable programmable read only memory (EPROM) and electrically erasable programmable read only memory (EEPROM) components under the influence of gamma radiation. This problem has significance in military industry and space technology. Total dose results are presented for the JL 27C512D EPROM and 28C64C EEPROM components. There is evidence that EPROM components have better radioactive reliability than EEPROM components. Also, the changes to the EPROM are reversible, and after erasing and reprogramming all EPROM components are functional. On the other hand, changes to the EEPROM are irreversible, and under the influence of gamma radiation, all EEPROM components became permanently nonfunctional. The obtained results are analyzed and explained via the interaction of gamma radiation with oxide layers.
Virtual Cathode Oscillator under Various Cathode Radii with Intense Relativistic Electron Beam
Authors: Min-Woo Chong Min-Woo Chong , Myong-Chul Choi Myong-Chul Choi , Yun-Ho Seo Yun-Ho Seo , Gaung-Sup Cho Gaung-Sup Cho , Eun-Ha Choi Eun-Ha Choi , Han-Sup Uhm Han-Sup Uhm
Published: October 2002

An axially extracted virtual cathode oscillator has been fabricated. This ultra high power microwave generator consists of the “Chundoong” intense relativistic electron beam pulser (Max 600 kV, 88 kA, and 60 ns duration). In this experiment, a solid electron beam with a diode current of 21 kA is obtained from the operation at a diode voltage of 290 kV. The microwave frequency has been also measured to be 6.07 GHz, its maximum power of extracted microwave is about
520 MW, its conversion efficiency is about 8.5% at a cathode radius of 2.5 cm and the Anode-Cathode (A-K) gap is 5 mm. It has also been found that the propagating microwave mode is a combination of T
M
01 and the other higher modes from the gas discharge experiment in the air-filled transparent region. The experimental results for the extracted microwave frequency and its power from the axially extracted virtual cathode oscillator are shown to be in good agreement with those the 2-1/2-dimensional “MAGIC” simulations.
Electrical Properties of N Ion Implanted Layer in (1100)-Oriented 6H-SiC
Authors: Satoh Masataka , Tanabe Hitoshi , Nakamura Tomonori
Published: October 2002

The electrical properties of a N ion implanted layer in (1100)-oriented 6H-SiC are investigated by means of Van der Pauw and Hall effect measurements. The samples are implanted using N ions at an energy of 30 keV with a dose ranging from 5 ×1014 to 5 ×1015/cm2 at room temperature. The samples annealed at 1500°C for 10 min show very low sheet resistance of the order of 102 Ω/\Box. The low sheet resistance is correlated to the high electrical activation of N impurities in the implanted layer with good crystalline quality.
Influences of Floating Particles Produced by High-Pressure, Pulsed Glow Discharge on Excimer Laser Excitation
Authors: Imada Go , Shinkai Takahiro , Masuda Wataru , Yatsui Kiyoshi
Published: October 2002

The floating particles produced by the high-pressure, pulsed glow discharge on KrF excimer laser excitation have been visualized by the pulsed-laser scatter method. The double-pulse discharge experiments have also been carried out to study the effects of the floating particles on the discharge instabilities. The particles with diameters of the order of 100 µm are observed in the discharge region just after the discharge. The number density of the particles increases to ∼2 particle/cm3 at 200 ms after the discharge, and then decreases to ∼1 particle/cm3 at 500 ms. In the double-pulse experiment without gas flow, the probability of arc formation in the second discharge reduces at 300 ms after the first discharge. It has been clearly demonstrated that the floating particles of the order of 100 µm hardly affect the discharge characteristics.
The Effect of the Growth Temperature on Polyoxide by Rapid Thermal Processing
Authors: Chang Kow Ming , Lee Tzyh Cheang , Sun Yong Long
Published: October 2002

A rapid thermal oxynitridation process using N2O gas as the oxidant has been developed. Due to a smoother polyoxide/polysilicon interface, polyoxide grown by rapid thermal processing has better reliability than that of polyoxide grown by a conventional furnace. Moreover, in order to explore the effects of growth temperature on polyoxides, polyoxides were grown at different temperatures in this study. From this work, we find that polyoxide grown at low temperatures has better reliability than polyoxides grown at high temperature and exhibits improved characteristics such as higher breakdown electric field, less gate voltage shift, and larger charger-to-breakdown.
Improvement of Channel Mobility for Trench Metal-Oxide-Semiconductor Field Effect Transistor by Smoothing Trench Sidewall Surface
Authors: Yahata Akihiro , Urano Satoshi , Inoue Tomoki , Shinohe Takashi
Published: October 2002

Channel mobility (µeff) for a trench metal-oxide-semiconductor field effect transistor (MOSFET) can be significantly enhanced by smoothing the trench sidewall surface. A smoothed sample showed an increased µeff value, 520 cm2/Vs, at an effective electric field (E
eff) of 2.7×105 V/cm, which was almost equal to that of a planar MOSFET, although it showed slightly smaller values in higher E
eff regions.
Four-Thin Film Transistor Pixel Electrode Circuits for Active-Matrix Organic Light-Emitting Displays
Authors: He Yi , Hattori Reiji , Kanicki Jerzy
Published: October 2002

Constant-current, four-thin-film-transistor (TFT) pixel electrode circuits, based on hydrogenated amorphous silicon (a-Si:H) TFT technology for active-matrix organic light-emitting displays (AM-OLEDs), have been designed, fabricated, and characterized. Experimental results indicate that continuous pixel electrode excitation can be achieved with these circuits. The pixel electrode circuits use a current driver to automatically adjust their current level for threshold voltage shifts of both the organic light-emitting devices and the drive TFT. Consequently, these pixel electrode circuits have excellent electrical reliability even when a large threshold voltage shift is present. A high output current level and a good output-input current linearity have been demonstrated with these circuits.
Dislocation-Free Czochralski Silicon Crystal Growth without Dash Necking
Authors: Huang Xinming , Taishi Toshinori , Yonenaga Ichiro , Hoshikawa Keigo
Published: October 2002

Dislocation-free silicon crystals which underwent boron and phosphorus doping were grown by the Czochralski (CZ) method without Dash necking. The boron concentration limit in a silicon seed 7×7 mm2 in cross section without dislocations due to thermal shock was 1×1018 atoms/cm3 in ordinary CZ silicon-crystal growth. The maximum admissible discrepancy of boron concentration in the seed and grown crystal was 7×1018 atoms/cm3 without dislocations due to lattice misfit in the grown crystal. Silicon seeds with a boron concentration of 3×1018 atoms/cm3 were used to grow CZ silicon crystals from lightly boron-doped (p-type) or phosphorus-doped (n-type) silicon melt, yielding dislocation-free silicon crystals without the need for Dash necking. Heavily boron-doped silicon seed should thus be applicable in growing other practical lightly doped dislocation-free CZ-silicon crystals without the need for Dash necking.
Observation of Defects in Laser-Crystallized Polysilicon Thin Films by Hydrogenation and Raman Spectroscopy
Authors: Kitahara Kuninori , Nakajima Kazuo , Moritani Akihiro
Published: October 2002

The relationship between defects and Si-hydrogen bonds in laser-crystallized poly-Si thin films was investigated by Raman spectroscopy. Hydrogenation was performed using two techniques, plasma excitation and a low-damage technique using a hot-wire as the catalyzer. At least six peaks were detected in the Raman spectra after plasma hydrogenation: two were sharp and Lorentzian shaped even though they appeared in the region of local-vibration modes. These peaks were attributed to defects induced by plasma damage and laser crystallization. It was deduced that defects undetectable by Raman spectroscopy could be detected as Si-hydrogen bonds by hydrogenation.
Improvement of the Reliability of a Cu/W–N/SiOF Multilevel Interconnect by Inserting Plasma Enhanced Chemical Vapor Deposited W–N Thin Film
Authors: Kim Dong Joon , Sim Hyun Sang , Lee Seoghyeong , Kim Yong Tae , Kim Seong-Il , Park Jong-Wan
Published: October 2002

We have investigated the characteristics of a Cu/W–N/SiOF multilevel interconnect. The resistivity and surface roughness of the Cu film on a W–N/SiOF/Si substrate are better than those of the Cu film on a SiOF/Si substrate after annealing at 500°C for 30 min. These results are due to the W–N thin film inserted between the Cu and SiOF because the surface energy of the W–N film is greater than that of the SiOF film, which improves the wettability of Cu on the W–N film and prevents the agglomeration of the Cu film during the annealing process. Also, the stress evolution, current–voltage (I–V) characteristics and Rutherford backscattering (RBS) spectra reveal that the Cu/W–N/SiOF/Si interconnect has lower tensile stress and better electrical properties than the Cu/SiOF/Si interconnect, which is due to the stress relaxation and the improvement of the barrier performance as a result of inserting the W–N thin films.
Physical and Chemical Characterization of Reused Oxide Chemical Mechanical Planarization Slurry
Authors: Kim Hyung-Joon , Eom Dae-Hong , Park Jin-Goo
Published: October 2002

The recycle of Chemical Mechanical Planarization (CMP) slurries has been actively considered in the industry to reduce the cost-of-consumables (COC) because of the sharp increase of the consumption of slurry in CMP. The main purpose of this study was to characterize the used oxide slurry physically and chemically to establish a means of reprocessing it. The characteristics of slurry were determined according to pH, solid content, specific gravity and particle size. These characteristics were affected and varied by deionized water inflow during the CMP process. The tetraethylorthosilicate removal rate was strongly dependent on the solid content and pH of slurry solutions. The solid content played a major role in determining the removal rates. Regardless of the number of polishings, the removal rate was almost the same at a solid content when it was modified by adding new slurry. The mean particle size of slurries did not change at all even in the five times recycled slurry. Even though there was a slight increase in the fraction of large particles in the range of 20 to 120 µm in the recycled slurries, no changes in thickness uniformity or defect density were observed when polishing was performed in either new or recycled slurry.
Etching Selectivity and Surface Profile of GaN in the Ni, SiO2 and Photoresist Masks Using an Inductively Coupled Plasma
Authors: Chang Liann-Be , Liu Su-Sir , Jeng Ming-Jer
Published: October 2002

The selectivity and etched surface profile for etching GaN using an inductively coupled plasma (ICP) in Ni, SiO2 and photoresist masks were investigated. The mask etching rates in the Ni, SiO2 and photoresist masks were 26, 70 and 245 nm/min, respectively, for a RF power of 500 W, an ICP power of 600 W and an etching gas ratio of BCl3/Ar/N
2=15:5:10 (sccm). A high selectivity of 15 in the Ni mask was found to be higher than that of 5.6 and 1.65 in the SiO2 and photoresist masks, respectively. The best etching surface profile was also obtained in the Ni mask in comparison with the SiO2 or photoresist mask.
Partial Recovery of Photodegradation at Room Temperature in Hydrogenated Amorphous Silicon
Authors: Shimizu Tatsuo , Maehara Takanori , Mitani Masahiro , Kumeda Minoru
Published: October 2002

Detailed ESR measurements disclosed that neutral Si dangling bonds (DBs) created by light soaking (LS) disappear partially at room temperature in a few hours after LS. In contrast metastable DBs created by thermal quenching remain unchanged at room temperature. It is suggested that a part of the Si DBs created by LS have a small activation energy for thermal annealing.
High Average Power Diode End-Pumped Composite Nd:YAG Laser Passively Q-switched by Cr4+:YAG Saturable Absorber
Authors: Pavel Nicolaie , Saikawa Jiro , Kurimura Sunao , Taira Takunori
Published: October 2002

We report a diode end-pumped composite Nd:YAG laser, passively Q-switched by a Cr4+:YAG crystal as saturable absorber. The maximum peak power exceeded 16 kW for an average power of 2.6 W, laser pulses of 16.8-ns duration and 272-µJ energy. The maximum average power was 4.2 W with the laser operating at 24.0 kHz repetition frequency and 47.8-ns pulses duration (3.7 kW peak power) at a beam quality of M
2=1.34. A rate-equation model that considers both the active medium and the saturable absorber dynamics was developed. A good agreement between the experiments and modeling resulted.
Erasing and Jitter Variation Mechanisms of Ag–In–Sb–Te Compact Disk-Rewritable at Double and Quadruple Compact Disk Velocities
Authors: Chou Lih-Hsin , Chang Yem-Yeu
Published: October 2002

The erasing mechanisms of Ag–In–Sb–Te compact disk rewritable (CD-RW) at CD 2× and CD 4× are studied by employing transmission electron microscopy (TEM). The mechanisms of laser-induced crystallization vary with linear velocity as well as erase power. Under CD 2× recording, erasing proceeds with nucleation and grain growth at low erase laser power. However, it is the direct grain growth that controls the mechanism of erasing at high erase laser power. Under CD 4× recording, erasing is dominated by direct grain growth originating from the interface between amorphous marks and their neighboring crystalline region, and the erase power determines the location where grain growth begins. In addition, a sharp increase in jitter after overwriting at CD 4× was observed as a result of the existence of two different amorphous marks. One of them has a normal shape and the other is extended with a tail in the trailing part. For overwriting more than 50 times, only one type of amorphous mark with a tiny sharp tail was observed. This single type of amorphous mark gives rise to a decrease in jitter.
Coupling from Laser Diode Bar to Single-mode Fiber Using a Stubbed Waveguide
Authors: Xu Jianqiu , Prabhu M. , Lu Jianren , Ueda Ken-ichi
Published: October 2002

We demonstrate a simple method for coupling from a laser diode bar to a single-mode fiber using a stubbed waveguide. The stubbed waveguide serves as a mode homogenizer that converts the rectangular multimode distribution of the emission of the laser diode bar into a circular beam with a smooth profile. Then the output beam is coupled to the lensed single-mode fiber. With this method, a laser diode bar operating at 795 nm is coupled into a 4 km single-mode silica fiber and the first order of stimulated Raman scattering of 100 mW in the fiber is observed.
Wavelength Dependence of Femtosecond Pulsed Laser Deposition of Zinc Oxide Films
Authors: Okoshi Masayuki , Higashikawa Kouji , Hanabusa Mitsugu
Published: October 2002

We used 130-fs, 790-nm and frequency-doubled 395-nm laser pulses to study the wavelength dependence of femtosecond pulsed laser deposition of Al-doped ZnO films. The short wavelength pulses helped to increase deposition rates, decrease electrical resistivity of the films, and reduce droplets mixed into deposits. The transmission property of the films in the visible range was unchanged by the frequency doubling. The optical emission study showed a reduction of ion emissions and increase of kinetic energy when the 395-nm pulses were used.
Mechanism of Blue-Shift of Mn2+ Luminescence in ZnMgS:Mn for Electroluminescent Thin Films
Authors: Kunio Ichino Kunio Ichino , Hiroaki Misasa Hiroaki Misasa , Masahiko Kitagawa Masahiko Kitagawa , Shosaku Tanaka Shosaku Tanaka , Hiroshi Kobayashi Hiroshi Kobayashi
Published: October 2002

The mechanism of the blue-shift of Mn2+ luminescence in ZnMgS:Mn is studied. Single crystal zincblende Zn1-x
MgxS:Mn thin films (x≤0.50) were grown by molecular beam epitaxy on GaAs substrates. The photoluminescence (PL) spectrum of Zn0.50Mg0.50S:Mn peaks at 572 nm, which is 12 nm shorter than the PL peak wavelength of ZnS:Mn. The PL excitation spectrum of Zn1-x
MgxS:Mn has five excitation bands due to the energy levels of Mn 3d5 electron configuration. These excitation bands shift to shorter wavelengths with increasing Mg content. The cause of these shifts seems to be a weakening of the crystal field due to an increase in the distance between Mn and S. The ratio of the shift in emission energy to the relative change in lattice constant, ΔE/(Δa /a), is found to be 2.3 eV (23 meV/%). This value is approximately half the value of the Mn emission in ZnS:Mn under high pressure.
Frequency Dependent Dielectric Breakdown of Thin Polyimide Films Prepared by Vapor Deposition Polymerization
Authors: Miyairi Keiichi
Published: October 2002

Dielectric breakdown of thin polyimide films prepared by vapor deposition polymerization has been investigated for various ac voltages. Real time measurements were made automatically with a system composed of a digital oscilloscope, controllable signal generator and microcomputer. The self-healing breakdown takes place at the peak of the applied voltage. The ac electric strength decreases with temperature, and it increases with frequency in the range of 10 Hz–3 kHz. The frequency dependent breakdown has been explained tentatively in terms of the establishment of a conductive path leading to the breakdown.
Trap Concentration Dependence on the Electrical Properties of Annealed Ultrathin Fluorinated Silicon Oxides
Authors: Chang Wai-Jyh , Houng Mau-Phon , Wang Yeong-Her
Published: October 2002

In this study, the electrical properties of ultrathin (5–9 nm) liquid-phase-deposited fluorinated silicon oxides (LPD-SiOFs) are investigated under various annealing conditions. The electron tunneling current at E
ox=4–6 MV/cm is suggested to be modeled by a generalized trap-assisted tunneling (GTAT) mechanism with consideration of trapezoidal- and triangular-barrier tunnelings. This gives the trap concentration (N
t) and the trap energy level (Φt) of a trapped oxide that is induced by fluorine incorporation. The reported Φt of fluorine is around 1.98–2.2 eV while N
t for O2-annealed LPD-SiOF is 1×1016–3×1018 cm-3 and N
t for N2O-annealed LPD-SiOF is 5×1014–2×1015 cm-3, depending on the annealing conditions. The trap concentration within the LPD-SiOF film is demonstrated to decrease with an increase in annealing temperature and time. From the GTAT modeling of O2- and N2O-annealed LPD-SiOF films, it is obvious that nitridation in N2O can substantially reduce the concentration of traps (by an order of magnitude of two) contained in original LPD-SiOF films. The flat-band voltage shift, interface trap density, constant current stress (CCS), and constant voltage stress (CVS) all show that LPD-SiOF annealed in N2O has the best material quality in comparison with others. As shown in the experimental and modeling results, the traps are found to be strongly dependent on the impurities contained in the oxide films (F or N atoms in this study). Using the GTAT model, we can derive the trap energy level and trap concentration simply from the current–voltage (I–V) characteristics without the use of other complicated measuring techniques.
Effect of LaNiO3 Electrode on Electrical Properties of RF-Magnetron-Sputtered Pb(Zr,Ti)O3 Ferroelectric Thin Films
Authors: Chao Gwo-Chin , Wu Jenn-Ming
Published: October 2002

Thin films of Pb(Zr,Ti)O3 (PZT) were rf-magnetron sputtered on both (100)-textured LaNiO3 electrode and Pt electrode. In the presence of the (100)-textured LaNiO3 electrode, a pure perovskite phase of (100) preferred orientation could be obtained at substrate temperatures as low as 450°C. In contrast, the residual pyrochlore phase was present in films deposited on the Pt electrode. In addition to lowering the fabricating temperature, the LaNiO3 electrode increases the relative dielectric constant and markedly decreases the coercive field of PZT films. Most beneficially, the LaNiO3 electrode not only improves the fatigue resistance but also reduces the leakage current of PZT films.
Improvement of Aberration Properties of Liquid Crystal Microlenses using the Stacked Electrode Structure
Authors: Honma Michinori , Nose Toshiaki , Sato Susumu
Published: October 2002

Optical properties of liquid crystal (LC) microlenses using a stacked electrode structure are studied, experimentally and theoretically. Detailed electric potential distribution properties and liquid crystal molecular orientations are investigated using computer simulations in order to discuss a relationship between interference fringe patterns and applied voltages of four electrode layers. An optimum condition so that the interference fringe patterns become symmetric is clearly derived from the simulation results. Spherical aberration and astigmatism properties are also discussed, and they are compensated by adjusting the thickness of the LC layer and using an elliptically hole-patterned electrode. This work leads to the development of LC microlenses with large NA values and small aberrations.
Cholesteric Gratings Doped with a Dichroic Dye
Authors: Fuh Andy Ying-Guey , Lin Chi-Huang , Hsieh Ming-Feng , Huang Chi-Yen
Published: October 2002

We report the results obtained from the studies of cholesteric gratings doped with a dichroic guest-host dye, G206. First, a dye-doped planar cholesteric texture was switched to a fingerprint texture. Using the pump (Ar+ laser)–probe (He–Ne laser) technique, we then studied the diffraction characteristics of the Raman-Nath cholesteric grating. The results showed that the diffraction efficiencies of the first- and second-order diffracted beams decreased and increased, respectively, with increasing power of the pump beam, while those of the zeroth order remained unchanged. In addition, the diffracted beams can be steered using the pump beam. We propose a model based on the thermal effect resulting from the dye absorption of the pump beam. It explains the experimental results qualitatively well.
Nanocrystallization Characteristics of Amorphous (Fe0.99Mo0.01)78B13Si9 and Fe78B13Si9 Alloys Treated by Shock Wave
Authors: Liu Ying Kai , Liu Zuo Quan , Wang Guang Hou
Published: October 2002

It is found that these amorphous alloys have been transformed into crystalline phase with grain size of 20–40 nm after annealing at temperature from 450–550°C for 30 min. Some new phases such as Fe3Si are observed and the lattice constant of α-Fe is shortened. These can not be explained by the previous theory about process of diffusion, nucleation and growth of the crystals.Instead, we explain the experimental results by the model of free volume and shearing deposition. If properly applied, shock wave treatment of amorphous alloys would be a promising method for synthesizing new crystalline phases of multi-component systems.
Visualization of Rubbing Nonuniformity by Double Surface Treatments of Polyimide-Coated Substrate for Liquid Crystal Alignment
Authors: Chung Doo-Han , Takanishi Yoichi , Ishikawa Ken , Takezoe Hideo , Park Byoungchoo
Published: October 2002

A new method for characterizing rubbing nonuniformity in liquid crystal cells is proposed. Homogeneously aligned cells made by rubbing apparently give a uniform texture under a polarizing microscope. However, nonuniformity of rubbing becomes apparent as scratched patterns, if the rubbing is preceded by rubbing or photoalignment processes. On the other hand, it was found that photoalignment gives quite a uniform texture even on a priori photoaligned surfaces. Thus the double surface treatments along different directions visualize the nonuniformity of rubbing, supplying a tool to examine the condition of the rubbing machine used including buffing cloths.
Scintillation Characteristics and Radiation Damage of Ce-Doped Bi4Si3O12Single Crystals
Authors: Harada Kenji , Ishii Mitsuru , Senguttuvan Nachimuthu , Kobayashi Masaaki , Nikl Martin , Feng Xi-Qi
Published: October 2002

We have analyzed the scintillation characteristics such as light yield and decay time and the radiation damage of Ce-doped Bi4Si3O12(BSO) single crystals grown by the vertical Bridgman method. Ce was doped into BSO at 0.1, 0.2 and 0.4 at.% and the grown crystals were analyzed. For the Ce doping at 0.1 at.%, the light yield decreased by 40% while the average decay constant decreased by 20% (from 105 ns to 86 ns). Radiation damage was assessed by measuring the optical transmittance before and after irradiating the crystals with60Co γ-rays for a maximum accumulated dose of 107rad. Significant improvement was found for the radiation hardness of Ce-doped BSO.
β-FeSi2 Single Crystals Grown from Solution
Authors: Udono Haruhiko , Kikuma Isao
Published: October 2002

We have grown high-quality β-FeSi2 bulk single crystals by a temperature gradient solution growth method using Ga solvent. Polyhedral shaped bulk crystals with clear facet planes were obtained below the growth temperature of 900°C. Laue observation confirmed that crystals are high-quality single crystals without twins. Full-width at half maxim of the X-ray rocking curve at β-FeSi2 (800) reflection was 53 arcsec. The conduction was p-type and the resistivity was 0.03–0.04 Ωcm at room temperature.