bluuebunny/crossref_metadata_2025 huggingface dataset:
Nano-Indentation for Structural Analysis of Hydrogen- and Nitrogen-Containing Carbon Films
Authors: Daisuke Tanaka Daisuke Tanaka , Shigeo Ohshio Shigeo Ohshio , Hidetoshi Saitoh Hidetoshi Saitoh
Published: October 2002

It is known that films of hard carbon materials, so-called hydrogenated diamond-like carbon (DLC:H) and nitrogen-containing DLC:H (DLC:N:H), are composed of medium-range ordered clusters. In this study, the boundary structure among medium-range ordered clusters is analyzed using a nano-indentation creep technique. DLC:H and DLC:N:H films were annealed at temperatures up to 500°C for 10 h. Raman spectroscopy revealed that thermal annealing promoted the increase in the boundary proportion among clusters. The strain-rate sensitivity coefficient, m, of the film also indicated that cluster flow became notable with thermal annealing. The increase in cluster flow is understood in terms of the growth in the number of boundaries. Although these phenomena were observed in both DLC:H and DLC:N:H films, the degree of flow in the DLC:N:H film was greater than that in the DLC:H film after thermal annealing. The flow characteristic was enhanced by nitrogen incorporation into the carbon cluster and/or nitrogen terminating the carbon cluster, suggesting that nitrogen incorporation promoted the formation of a thermally instable and mechanically deteriorated structure.
Production of Heat during Plasma Electrolysis in Liquid
Authors: Mizuno Tadahiko , Ohmori Tadayoshi , Akimoto Tadashi , Takahashi Akito
Published: October 2002

Plasma was formed on the surface of an electrode in a liquid solution when metal cathodes underwent high-voltage electrolysis. A real-time heat calibration system was designed for detecting the amount of heat generated during plasma electrolysis. The measured heat exceeded the input power substantially, and in some cases 200% of the input power. The heat generation process depended on the conditions for electrolysis. There was no excess heat at the beginning of plasma electrolysis. However, after plasma electrolysis for a long time, a large amount of heat was generated. The reproducibility would be 100% if all factors such as temperature, voltage and duration were optimized. Based on the heat and the products, we hypothesize that some unique reaction occurs on the cathode surface. This reaction may not occur at energy levels available during electrochemical electrolysis.
A Possible Model for Changes in Photoluminescence Wavelength of Porous Si due to Photochemical Etching
Authors: Yasumori Yoshio , Kimura Hideki , Okada Takumi , Choe Il yong , Sato Yoichi , Iida Masamori , Kurosu Tateki
Published: October 2002

The changes in wavelength of photoluminescence (PL) along the depth direction of porous silicon (PS) have been investigated using the well known photochemical etching (PE) treatment technique. It was found that in both thicker and thinner PS samples, there existed a range where the PL output wavelength changed significantly from longer to shorter and irregular changes in the PL wavelength were observed. These results are in contrast with the result reported previously. On the basis of the band gap widening and the enhanced radiative recombination efficiency due to quantum confinement, i.e., quantum size effect, a qualitative model to explain these behaviors was proposed.
Molecular Beam Time of Flight Analysis of the Reaction Dynamics of Alkane Molecules Interacting with a Pt(111) Surface
Authors: Hiraoka Tomomi , Yagyu Sinjiro , Kondo Takahiro , Ikeuchi Toshiyuki , Yamamoto Shigehiko
Published: October 2002

Molecular beam time-of-flight analysis has been applied to investigate the
reaction dynamics of hyperthermal alkane molecules such as methane and ethane
interacting with a Pt(111) surface. Below the threshold incident kinetic energy and
surface temperature, where direct inelastic collision is dominant, the velocity
distributions of scattered methane and ethane molecules qualitatively agree with the
prediction based on the classical cube model [R. M. Logan and R. E. Stickney:
J. Chem. Phys. 44 (1966) 195.]. Rotational mode excitation is found to be
much more significant in the case of ethane molecules than methane molecules. Once
dissociation occurs, however, reaction products roughen the surface and reduce the
effective mass of the surface, which makes the model no longer applicable. The
deviation from the prediction can be understood as a result of increased tangential
energy transfer and the multiple collision of incident molecules at the interacting
surface.
Debinding Process of Fe–6Ni–4Cu Compact Fabricated by Metal Injection Molding
Authors: Wang Jenn-Shing , Lin Shih-Pin , Hon Min-Hsiung , Wang Moo-Chin
Published: October 2002

The debinding process in the case of metal injection molding for fabrication of the Fe–6Ni–4Cu compact and variables such as temperature and time has been studied. The debinding process of multiple organic binders in the Fe–6Ni–4Cu compact was investigated by thermal gravimetric analysis (TGA) weight loss and mercury porosimetry analysis. The weight loss of wax and SA dramatically increases from below 10 wt% to 76.0 wt% and 86.0 wt% after immersion in 35°C and 40°C n-hexane for 6 h, respectively. The interdiffusion coefficients of the binder and solvent are 9.763×10-7cm2/s and 1.295×10-6cm2/s, respectively. The temperature dependent interdiffusion coefficient for the Fe–6Ni–4Cu compact can be expressed asDx=4.534×10exp (-5437.2/T). The distribution of pore size is about 0.1–1.9 µm for the Fe–6Ni–4Cu compact.
Electroluminescence from Barrier-Type Anodic Oxide Alumina Films Doped with Rare-Earth and Transition Metals by Ion-Implantation
Authors: Maeno Tomokazu , Morisaki Shigeyoshi
Published: October 2002

Electroluminescence (EL) during reanodization of a barrier-type anodic oxide alumina film (barrier alumina film) doped with rare-earth and transition metals was observed. To dope the rare-earth and transition metals into the barrier alumina films, an ion-implantation technique was employed. The sharp emissions from the barrier alumina films doped with rare-earth metals were assigned to the 4f–4f transitions of the trivalent elements, with the exception of Ce which was assigned to the 5d–4f transitions. With the doping of multiple elements, the emission spectrum was a mixture of the spectra of all elements, that is, the emission color of each element was mixed to exhibit a certain color.
Physical Vapor Deposition of Hexagonal and Tetragonal CuIn5Se8 Thin Films
Authors: Kohara Naoki , Nishiawaki Shiro , Negami Takayuki , Wada Takahiro
Published: October 2002

Hexagonal and tetragonal CuIn5Se8 thin films have been successfully prepared by physical vapor deposition. A hexagonal CuIn5Se8 thin film was obtained via the reaction of (Cu+Se) and (In+Se) layers. This hexagonal film had a layered structure with a lattice spacing of approximately 16 Å, corresponding to fivefold close-packed stacking of Se. With an alternative deposition process using (CuInSe2) and (In2Se3) layers, a tetragonal CuIn5Se8 thin film was obtained. The tetragonal film had a columnar structure with a lattice spacing of 3.3 Å, corresponding to the cubic close-packed stacking of Se. As evident from examination of the Cu2Se–In2Se3 pseudo-binary system phase diagram, hexagonal CuIn5Se8 is a stable phase and tetragonal CuIn5Se8 is metastable. The growth mechanism of the hexagonal and tetragonal phase CuIn5Se8 thin films is discussed from a crystallographic point of view.
Introduction of Selectively Nucleated Lateral Crystallization of Lead Zirconate Titanate Thin Films for Fabrication of High-Performance Ferroelectric Random Access Memory
Authors: Lee Jang-Sik , Joo Seung-Ki
Published: October 2002

We found that large single grains of lead zirconate titanate (PZT) thin film of which grain size was as large as 40 µm in length could be fabricated by lateral crystallization from the seeds. The seeds were prepared on the Pt substrate in the form of crystallized PZT dots. The electrical characteristics of PZT thin films (Pt/PZT/Pt structure) obtained by selectively nucleated lateral crystallization (SNLC) were found to be superior to those of polycrystalline PZT thin films. PZT thin films obtained by SNLC showed a leakage current density of 8×10-8 A/cm2, a breakdown field of 1240 kV/cm, a saturation polarization of 42 µC/cm2, and a remanent polarization of 30 µC/cm2. No degradation of the electrical properties was observed even after 2×1011 cycles using 1 MHz square wave form at ±10 V. Retention test revealed no appreciable data loss after 30000 s of memory retention at room temperature.
Bend Transition in Pi-cell
Authors: Nakamura Hajime , Noguchi Michikazu
Published: October 2002

Despite lack of knowledge on the nucleation process, the bend domain growth is observed as a motion of disclinations, whose velocity can be determined from the energy difference between two states by applying the boundary-layer model and a damping factor. The disclination velocity is proportional to the electric field across the cell. Upon application of a bias, a transient splay state having a fast bend spreading velocity emerges, which then changes into the asymmetric splay state very quickly, leaving the average bend spreading velocity very low. When the bias voltage drops down to zero, the asymmetric splay state relaxes back to a homogenous state, which, applying the bias voltage again, returns to the transient splay. The repetition of turning on and off the bias voltage enhances the average bend advancing velocity, and therefore is useful for fast bend transitions in an active-matrix liquid crystal display.
Methods and Concerns of Compensating In-Plane Switching Liquid Crystal Displays
Authors: Anderson James E. , Bos Philip J.
Published: October 2002

It is well known that uncompensated in-plane switching (IPS) liquid crystal displays (LCDs) have much better viewing angle than conventional twisted-nematic (TN) LCDs. However, to achieve optimal viewing angle performance in these devices, they must be compensated by one or more films. In this paper, we will study the optimization of such compensation. We will show the benefit of using polarizers which do not have a birefringent substrate. We will also show the effect of which side of the LCD the compensation films are placed. Finally, we will investigate the surprising effect of the pretilt angle on the viewing angle of the compensated IPS LCD.
Red Electroluminescence from an Organic Europium Complex with a Triphenylphosphine Oxide Ligand
Authors: Hu Wenping , Matsumura Michio , Wang Mingzhao , Jin Linpei
Published: October 2002

An Eu-complex, europium tris(dibenzoylmethide) (triphenylphosphine oxide), was newly synthesized and utilized as a light-emitting material in electroluminescent devices. The complex was easily deposited as transparent and homogeneous thin films by vacuum sublimation,and was successfully applied to electroluminescent devices with a stacked structure of indium-tin-oxide (ITO)/hole transporting layer/Eu-complex layer/hole blocking layer/electron transporting layer/cathode. The devices with this structure gave off pure red light with luminance as high as 320 cd/m2. The hole-blocking layer was essential to obtain pure red light from this Eu-complex. Without the hole-blocking layer, holes passed through the Eu-complex layer and entered into the electron transporting layer, leading to yellow emission.
Surface Tension Variation of Molten Silicon Measured by Ring Tensiometry Technique and Related Temperature and Impurity Dependence
Authors: Hideo Nakanishi Hideo Nakanishi , Kenichi Nakazato Kenichi Nakazato , Kazutaka Terashima Kazutaka Terashima
Published: October 2002

The surface tension of non doped, gallium-doped and boron-doped silicon melts has been measured as a function of temperature in purified argon atmosphere (oxygen partial pressure was less than 10-8 MPa) using the ring tensiometry technique. In all cases, the surface tension decreases linearly with increasing temperature. The surface tensions of γ={763-0.219×(T-T
m)}×10-3 N/m in the non doped silicon melt, γ={777-0.243×(T-T
m)}×10-3 N/m in the gallium-doped silicon melt and γ={721-0.098×(T-T
m)}×10-3 N/m in the boron-doped silicon melt were obtained. We have found that the surface tension of the silicon melt depends on the species of impurity. However, the surface tension anomaly near the solidification point previously reported by Sasaki et al. [1] was not observed under any experimental conditions.
Model Test of Biperiodic L-support Disk-and-Washer Linac Structure
Authors: Hiroyuki Ao Hiroyuki Ao , Makoto Inoue Makoto Inoue , Yoshihisa Iwashita Yoshihisa Iwashita , Toshiyuki Shirai Toshiyuki Shirai , Akira Noda Akira Noda
Published: October 2002

A disk-and-washer (DAW) structure with biperiodic L-support was studied. Aluminum models were fabricated by calculation studies. Information for tuning the frequency was accumulated through cold model measurements. The material strength of oxygen free copper (OFC) was measured for the fabrication of the high-power model fabricated with OFC. A load test confirmed that OFC was enough sufficiently strong for this structure, although the DAW has structural complexity. On the basis of these results, eleven two-cell-units with a high-power model cavity made of OFC were fabricated. The accelerating mode and coupling mode frequencies of the entire structure were evaluated to be -1.1 MHz and -3.5 MHz, respectively, within the operating frequency of 2857 MHz, and ±2% electric field flatness was achieved. These values are sufficient for the requirements of a high-power model. A detailed design which aimed at electron acceleration was established for the DAW structure with biperiodic L-support.
Strong Mechanoluminescence from UV-Irradiated Spinels of ZnGa2O4:Mn and MgGa2O4:Mn
Authors: Matsui Hiroaki , Xu Chao-Nan , Akiyama Morito , Watanabe Tadahiko
Published: October 2002

The mechanoluminescence (ML) from spinels of MgAl2O4:Mn (MAO:Mn), MgGa2O4:Mn (MGO:Mn) and ZnGa2O4:Mn (ZGO:Mn) has been investigated. It was found that the MGO:Mn and ZGO:Mn gave a strong ML response and a long-lasting phosphorescence (LLP). On the contrary, MAO:Mn exhibited very weak ML and no LLP. The high ML intensity of MGO:Mn and ZGO:Mn is attributed to a large number of trapped carriers which has been clarified by the measurement of thermoluminescence. The carrier traps in MGO:Mn and ZGO:Mn are assumed to be produced by the point defects due to the partially inverse spinel structure and the oxygen vacancies generated by heat-treatment in a reducing atmosphere. It is suggested that the trapped electrons in oxygen vacancies can be excited by the application of friction, and the resultant recombination between the excited electrons and the trapped holes in the point defects gives rise to an energy which can be transferred to Mn2+ centers to produce the green emission according to the transition 4
T
1(4
G)→6
A
1(6
S).
Photocarrier Generation Mechanism of Layered Organic Photoreceptor Using Two-Coupler-Based Bisazo Pigment
Authors: Niimi Tatsuya , Umeda Minoru
Published: October 2002

We have investigated the photocarrier generation mechanism of a layered organic photoreceptor containing two-coupler-based fluorenone bisazo pigment in comparison with the conventional bisazo pigment which has the same coupler components. The magnitude of quantum efficiency of both layered photoreceptors in a higher electric field approaches that of the charge separation efficiency of a photogenerated exciton to form a geminate hole-electron pair. The charge separation efficiency of the layered photoreceptor containing the asymmetrically structured bisazo pigment is about 1.5 times larger than that containing the symmetrically structured pigment. The charge separation is considered to be attributed to the photoinduced electron transfer; the disparity of the reaction rate could not be explained based on the energy gap. The size of the primary particles of asymmetrical azo is found to be about half the size of those of the symmetrical azo. It is therefore concluded that the high photosensitivity is due to the size of the azo pigment particles which practically induce a change in the number of charge separation sites.
Exchange Anisotropy of Monodispersed Co/CoO Cluster Assemblies
Authors: Peng Dong Liang , Sumiyama Kenji , Hihara Takehiko
Published: October 2002

Monodispersed Co/CoO cluster assemblies with the mean cluster size of
13 nm have been prepared using a plasma-gas-condensation-type cluster
beam deposition apparatus. The structural analysis and magnetic
measurement indicate that the Co cluster is covered by an oxide shell
composed of CoO. The effect of the oxygen gas flow rate during
deposition and that of temperature on the coercivity and hysteresis loop
shift induced by field cooling were measured. The effect of the CoO shell
on the loop shift and the temperature dependence of the exchange
anisotropy are discussed. The unidirectional anisotropy is negligible
above 200 K for the present assemblies. This is ascribed to the rapid
decrease of the anisotropy of the antiferromagnetic interfacial layers near
the interface of the Co cores and CoO shells.
Neutron Diffraction Measurement and Finite Element Method Calculation of Residual Stress of a Heat Treated Steel Pipe
Authors: Inoue Kazuko , Kawashima Hisakazu , Sakaguchi Junya , Minakawa Nobuaki , Tsuchiya Yoshinori , Morii Yukio
Published: October 2002

The residual strain of a 13% Cr steel pipe for use in oil wells was measured by neutron diffraction. As the pipe was quenched from 900°C to room temperature by spraying water at 30°C on the outer surface of the pipe for 30 s, it should be exposed to thermal stress. To measure the strain in the pipe, the residual stress analyzer (RESA) using neutron diffraction at Japan Research Reactor No. 3 Modified (JRR-3M) was used. Three directional measurements were carried out at intervals of 1 mm for the wall thickness of 5.51 mm. The residual stress deduced from the observed strain showed that the stress in the axial direction was tensile near the outer surface and compressive near the inner surface. The deduced stress was compared with the stress calculated by the finite element method (FEM).
Phase Transitions and Structures in Langmuir–Blodgett Films
Authors: Mami Takahashi Mami Takahashi , Hiroyuki Kaji Hiroyuki Kaji , Yuhei Shimoyama Yuhei Shimoyama
Published: October 2002

In order to reveal phase transitions and structures of organic ultra-thin films, we made temperature dependence measurements of X-ray diffraction (XRD) and differential scanning calorimetry (DSC) on both Langmuir–Blodgett (LB) films and powder of manganese-arachidate salt. Unlike pure arachidic acid, DSC measurements of the manganese–arachidate powder showed two-phase transitions, i.e., the main transition and a new transition, or pretransition. XRD measurements of the LB films confirmed the two-phase transitions, and three phases, namely, a lamellar phase with a certain tilt, a lamellar phase without tilt, and an ordered fluid phase with melted alkyl-chains. The findings indicate that the phase behavior plays a key role in the fabrication mechanics of LB films of transition metal–fatty acid salt, such as the temperature control during the monolayer formation and annealing processes.
Dynamical Features of the Local Fractal Dimension of Brain Waves and Its Applicability for Diagnosis of Senile Dementia
Authors: Ryoya Saji Ryoya Saji , Hidetoshi Konno Hidetoshi Konno
Published: October 2002

We have studied local irregularity of brain waves using “local fractal dimensions (LFDs)” for two groups of elderly people, one healthy and the other affected by senile dementia. It is determined that (a) the probability distribution of the LFDs for both groups is subject to the universal law of the beta distribution; (b) the stochastic processes of LFDs of the two groups show a marked difference. We have demonstrated the applicability of the present statistical method based on the LFD for estimating the degree of progression of dementia.
AlSixOy as a High-Transmittance Embedded Material of Ternary Attenuated Phase-Shifting Mask and Correlation between Chemical Composition and Optical Properties of AlSixOy in 193 nm Lithography
Authors: Lin Cheng-Ming , Loong Wen-An
Published: October 2002

AlSi
x
O
y
(Al:Si:O=1:0.36:0.88) thin film has the potential for use as a new and high-transmittance (T%∼35%) embedded layer of an attenuated phase-shifting mask (AttPSM) in 193 nm lithography. Increasing the compositions of Al2O3, SiO2 and other oxides increases n and decreases k in AlSi
x
O
y
. Compared to a conventional AttPSM (T%<10%), the high-T% AttPSM assisted by opaque Cr scattering bars can achieve a greater depth of focus, 0.45 µm for a 0.10 µm isolated line. Under the conditions of BCl3/Cl2=30/7 sccm, chamber pressure 3 mTorr, source power 1400 W and RF bias power 30 W, the etching selectivity of AlSi
x
O
y
over positive resist EP-1EG is 7.7:1. Under those of BCl3/Cl2/O2=35/7/3.2 sccm, the selectivity of AlSi
x
O
y
over substrate fused silica is 5.8:1. A 0.25-µm-line/space (1:1) etched pattern was successfully fabricated using AlSi
x
O
y
as an embedded layer.
Contrast Measurement of Reflection Masks Fabricated from Cr and Ta Absorbers for Extreme Ultraviolet Lithography
Authors: Masahito Niibe Masahito Niibe , Takeo Watanabe Takeo Watanabe , Hajime Nii Hajime Nii , Takeshi Tanaka Takeshi Tanaka , Hiroo Kinoshita Hiroo Kinoshita
Published: October 2002

We chose Cr and Ta metals as new absorbing materials for extreme ultraviolet lithography (EUVL) reflection masks. The transmittances of EUV light for these metals were calculated to be nearly equal to those for W metal at the wavelength of 13.5 nm. Reflection masks were successfully fabricated from Ta metal films by dry-etching and from Cr metal films by the lift-off technique. The mask contrast was measured using an EUV reflectometer system with a synchrotron radiation source. For the Cr absorber mask, measured peak reflectivities at the reflecting and the absorbing part of the processed patterns were 59% and 4.9%, respectively, and the contrast was about 12. The peak reflectivities at the reflecting and absorbing parts of the processed patterns for the Ta absorber mask were 50% and 0.48%, respectively, and the contrast was about 105. The masks, prepared about one year before the reflectivity measurements and stored in air, exhibited no significant degradation of reflectivity or surface quality. However, a 4% reduction in reflectivity was observed after two years' storage in air, even though the top layer of the Mo/Si multilayer for the masks was Si, which has been reported to prevent oxidation.
Azimuth Dependence of Solar Radiation on Inclined Surfaces II
Authors: Shibata Noboru
Published: October 2002

The author carried out an experiment to examine the azimuth
dependences of solar radiation on an inclined suface. An integrating
function recorder enabled measurements of solar radiation to be taken
under all atmospheric conditions. The amount of solar radiation was
determined to be greater on a westward-facing surface than on an
eastward-facing surface throughout the year.
Contrast Evaluation of the SCALPEL GHOST in 100 kV Electron Projection Lithography
Authors: Koba Fumihiro , Yamashita Hiroshi , Nomura Eiichi
Published: October 2002

We investigated the essential conditions for the SCALPEL GHOST for fabricating 80 nm devices in 100 kV electron projection lithography (EPL), in terms of the exposure intensity contrast. First, we estimated the energy backscattering coefficient, η, and the used resist contrast to be 0.76 and 23% by calculation and experiment at 50 kV. Then, using the obtained parameters and calculated exposure intensity contrast at 100 kV, we found that the SCALPEL GHOST will be applicable, with some resist improvements, when the beam blur of exposure systems, δ, is 45 nm or less.
Three-Dimensional Finite-Difference Time-Domain Analysis of Optical Disk Storage System
Authors: Xu Jingfeng Liu , Chong Tow Chong
Published: October 2002

A rigorous three-dimensional optical electromagnetic finite-difference time-domain (FDTD) modeling for the accurate analysis of an optical disk storage system is detailed. In this model, not only the complex material properties of typical optical storage systems, such as the magneto-optical (MO) disk and the phase-change optical disk, but also the complex aperiodic disk structure is considered. Moreover, the model enables us to consider the high-numerical-aperture optical storage system, which is a necessity in the consideration of the near-field optical recording. Numerical investigations of the optical ROM, the phase-change optical disk and the MO disk are presented as examples to demonstrate the utility of the model.
Critical Dimension Issues for 200 mm Electron Projection Masks
Authors: Resnick Douglas J. , Nordquist Kevin , Dauksher William J. , Ainley Eric , Lu Bing , Mangat Pawitter , Weisbrod Eric , Martin Carl , Chang J. , Englestad Roxann , Lovell Ed , Ivin Vladimir
Published: October 2002

Electron projection lithography (EPL) is one possible successor to conventional optical lithography. One type of EPL mask, a SCALPEL mask, consists of an array of rectangular membranes on a 200 mm silicon support wafer. An image of a die is formed by scanning and stitching the patterns resident on the membrane array. Key areas of concern for controlling the mask critical dimension (CD) include temperature uniformity during the resist post exposure bake (PEB) process, heating issues during resist exposure, fogging effects caused by electron scattering from the mask chuck and variations resulting from the pattern transfer of the mask scattering layer. A finite element model was used to evaluate heating issues during the mask writing step and PEB process. Masks were then written to verify the models. A Monte Carlo model was used to evaluate CD variations caused by electrons scattering from the chuck during the mask writing process.
Electron Scattering and Related Phenomena in Scattering with Angular Limitation Projection Electron Lithography (SCALPEL*)
Authors: Mkrtchyan Masis M.
Published: October 2002

Scattering with angular limitation projection electron lithography (SCALPEL) is a unique charged-particle projection imaging technique that employs a scattering mask with the pattern segmented between supporting struts. An aperture installed in the back-focal plane of the projection lens filters out the electrons scattered at large angles in the patterned area of the mask producing a high contrast aerial image. Various scattering phenomena involved with the energetic (100 keV) electrons carrying the mask pattern information to the wafer through the projection optics are responsible for the aerial image formation in SCALPEL. These phenomena can be grouped into three major categories: (i) electron elastic scattering in the mask responsible for the aerial image intensity and contrast; (ii) electron inelastic scattering in the mask-membrane that might have negative effects, such as membrane charging, beam chromatic blur generation, mask heating, etc.; (iii) Coulomb interactions of electrons in the beam (space charge effect) generating a beam blur that links the system throughput and resolution. Analytical models developed to describe and quantitatively evaluate these phenomena are briefly reviewed. The implication of these models to the design and optimization of the electron projection lithography systems are discussed.
EB Stepper-A High Throughput Electron-Beam Projection Lithography System
Authors: Yamaguchi Takeshi
Published: October 2002

The development program of an electron-beam (EB) stepper is under way based on the results of proof of the concept system. Very careful system consideration has been made, because some critical issues have not yet been proven. However, they could be well managed by implementing a new methodology that is introduced by examining each issue from the viewpoint of the basic electron optics principle. In this paper, the practicability and extendability of an EB stepper are discussed and overviewed.
Electron Cyclotron Resonance Plasma Etching of α-Ta for X-Ray Mask Absorber Using Chlorine and Fluoride Gas Mixture
Authors: Tsuchizawa Tai , Iriguchi Hiroki , Takahashi Chiharu , Shimada Masaru , Uchiyama Shingo , Oda Masatoshi
Published: October 2002

The etching of α-Ta deposited by electron cyclotron resonance (ECR) sputtering is investigated by an ECR ion stream with a mixture of chlorine and fluoride gases for use in the X-ray mask process. The addition of fluoride gas reduced the surface roughness of etched patterns caused by the crystal structure of ECR-sputtered Ta. However, Ta etching stopped completely when the concentration of fluoride gas was sufficiently high. This was because of oxygen generated from the plasma chamber. It was important to keep the amount of fluoride gas very small when etching Ta. Using a mixture of Cl2 and a small amount of CF4, we obtained patterns with vertical side walls and minimal roughness at widths less than 100 nm. We also evaluated the critical dimension (CD) uniformity and accuracy of actual X-ray masks and confirmed that the etching faithfully transferred resist patterns to the Ta. The change in pattern width during etching was less than 1.5 nm on average for three masks.
Deposition and Characterization of Ta, TaNx and Ta4B Films for Next-Generation Lithography Mask Applications
Authors: Lee Seung Yoon , Park Chang Mo , Ahn Jinho
Published: October 2002

Ta, TaN
x
and Ta4B thin films were sputter deposited and characterized for next-generation lithography (NGL) mask applications. The density values of these films were obove 15.5 g/cm3 and showed negligible change with deposition pressure. An amorphous-based microstructure was observed in TaN
x
and Ta4B films, while pure Ta shows a columnar crystalline structure. Amorphous microstructures exhibit better surface smoothness and suppressed oxygen diffusion, resulting in improved stress stability.
Line Width Variation due to Global Topography
Authors: Jin-Young Kim Jin-Young Kim , Eun-Mi Lee Eun-Mi Lee , Young-Mi Lee Young-Mi Lee , Eun-Jung Seo Eun-Jung Seo , Dong-Soo Sohn Dong-Soo Sohn , Young-Soo Sohn Young-Soo Sohn , Heung-Jin Bak Heung-Jin Bak , Hye-Keun Oh Hye-Keun Oh
Published: October 2002

To obtain the spun-on resist surface profile around a topographical feature, the analytical solution of an equation derived from mass continuity and the Navier-Stokes equation using the lubrication approximation was used. The final resist thickness profile was obtained by applying our previous experimental result of resist thickness reduction due to the soft bake process. We found that the difference in resist thickness could induce severe critical dimension variation. Since the resist height differences between above and far from the feature could be greater than the focus margin, a 180 nm line and space pattern could not be obtained for the entire area within the process latitude. To overcome this problem, we applied mask bias and an edge phase-shift mask. As a result, the desired line and space pattern was obtained for the entire global topographical area.
Performances of Novel Nozzle-Scan Coating Method
Authors: Ito Shinichi , Ema Tatsuhiko , Kitano Takahiro , Sho Kohtaro , Esaki Yukihiko , Morikawa Masateru , Takeshita Kazuhiro , Akimoto Masami , Okumura Katsuya
Published: October 2002

A novel dispenser-nozzle-scan coating (NS-coating) method was developed. NS-coating is very useful for reducing the coated volume and its cost. This method has two stages. The first stage is to form a fluid film on the substrate. The second stage is the vacuum drying process to evaporate the solvent with agitation to improve the thickness uniformity. In the first stage, one of the most important parameters of NS-coating is the relationship of the contact angle of the fluid film on the substrate surface to the scan pitch of the dispenser nozzle. The start and end positions of dispensation are also important in terms of avoiding projection. With selecting the solvent of a resist solution on the anti-reflection-layer (ARL) surface and optimizing the start and end positions of dispensation, the thickness uniformity of less than 2% was obtained in the solid state.
Polarization Effect on Signal from Optical ROM Using Solid Immersion Lens
Authors: Otaki Katsura , Osawa Hisao , Ooki Hiroshi , Saito Jun
Published: October 2002

In a high-numerical-aperture optical head using a solid immersion lens (SIL), it is
anticipated that the polarization of the diffracted beam is disturbed, this affects
the signals. To study this problem, a rigorous simulator based on the three-dimensional vector diffraction theory has been developed. Polarization
disturbance for various NAs has been estimated and it has been clarified that the
polarization is disturbed not only in the SIL head but also in the conventional high-NA
head whose disk substrate is not covered with protective glass. The influence of
polarization disturbance on the readout signals has been determined and discussed
for the various polarizations.
Typical Electron Beam Doping (Superdiffusion) of Impurity Atoms in Damage-Free Regions of Semiconductors by the Kick-Out Mechanism
Authors: Wada Takao , Fujimoto Hiroshi , Asada Shigeharu
Published: October 2002

Experiments involving 750 keV electron beam doping (EBD) of Si and Zn atoms into GaAs were performed for systems of GaAs (layer 3)/Si(Zn)//Si(Zn)/GaAs (layer 1). The Si(Zn)/GaAs consists of Si(Zn) evaporation-deposited layers on GaAs wafers. The overlying layer is in contact only with one other Si(Zn) layer. The surface of layer 3 (GaAs) was irradiated with a fluence of (∼3.7–5.0)×1017 electrons·cm-2 at 750 keV and at 100°C in a N2 gas atmosphere at a mean current density of 8.1 µA·cm-2 using a Van de Graaff accelerator. After irradiation, the remaining unreacted Si and Zn layers were carefully removed by chemical etching. It was confirmed by Auger electron spectroscopy that no Si or Zn layer remained on the wafer after etching. The unannealed GaAs crystals were measured by secondary ion mass spectrometry (SIMS) and photoluminescence (PL). The diffusion depth of Zn atoms increased with the thicknesses of the deposited layers.
Quantum Dots in Carbon Nanotubes
Authors: Ishibashi Koji , Ida Tetsuya , Suzuki Masaki , Tsukagoshi Kazuhito , Aoyagi Yoshinobu
Published: October 2002

A technology to fabricate electrical contacts on individual single-wall carbon nanotubes has been developed, and electrical measurements are carried out below 4.2 Kelvin. The electrical transport property at low temperatures has basically been characterized as a quantum dot with a pronounced Coulomb blockade effect and zero dimensional confined levels. A microwave response to the nanotube quantum dot is also studied to further characterize the quantum dot. It is discussed how and where the tunnel barrier is formed to realize the quantum dot in a sample. The microwave irradiation effect on the quantum dot turns out to be a classical modulation of the source drain voltage, and is discussed considering the various energy and time scales associated with the transport.
Imprint Lithography Using Triple-Layer-Resist and Its Application to Metal-Oxide-Silicon Field-Effect-Transisor Fabrication
Authors: Hiroyuki Nakamura Hiroyuki Nakamura , Akiyoshi Baba Akiyoshi Baba , Tanemasa Asano Tanemasa Asano
Published: October 2002

Imprint lithography using a triple-layer resist technique has been investigated. The triple-layer resist consisted of either novolac resin or polymethylmethacrylate (PMMA) for the top layer, Al for the intermediate layer, and novolac resin for the bottom layer. Molds made of crystal Si or porous-Si covered Si were prepared. The pattern transfer characteristic depending on pressure, substrate temperature during imprint, and mold material was investigated. It is found that imprinting at a substrate temperature close to the pre-bake temperature for the top resist is preferred for pattern transfer with high accuracy. The use of porous Si covered molds is shown to be effective for improving the uniformity. PMMA which has a relatively low glass-transition temperature is found to decrease the pressure required for the pattern transfer. It is also shown that mechanical stress applied to metal-oxide-silicon (MOS) capacitors does not affect the gate oxide integrity, as it is evaluated by time-dependent dielectric-breakdown. MOS field-effect transistors (MOSFETs) on SOI silicon-on-insulator (SOI) having the gate length of about 0.1 µm are fabricated using the imprint lithography. It is shown that imprint lithography does not degrade the performance of MOSFETs.
Lifetime and Spin Relaxation Time Measurements of Micro-Fabricated GaAs Tips
Authors: Ryoichi Shinohara Ryoichi Shinohara , Koichi Yamaguchi Koichi Yamaguchi , Hidenobu Hirota Hidenobu Hirota , Yoshishige Suzuki Yoshishige Suzuki , Takashi Manago Takashi Manago , Hiroyuki Akinaga Hiroyuki Akinaga , Takashi Kuroda Takashi Kuroda , Fujio Minami Fujio Minami
Published: October 2002

The lifetime and the spin relaxation time of excited electrons in GaAs microtips tailored for scanning tunneling microscope (STM) with spin polarization detection were measured by time-resolved polarized photoluminescence at room temperature. The electron lifetime obtained from the tip-fabricated p-type GaAs substrate was about 20 ps shorter than that obtained from the GaAs substrate without microtips. This is attributed to the enhanced surface recombination in the microtip. The spin relaxation time was comparable to the electron lifetime for the tip-fabricated GaAs substrate. From electron lifetime and spin relaxation time, a respectable spin polarization of about 20% was evaluated in the tip-fabricated GaAs substrate, which was about 1.2 times larger than that in the GaAs substrate without microtips, under the 0° incident angle of the excitation light. The influence of oblique incidence of the excitation light is also discussed.
Fabrication and Characterization of Pt-Oxide Electrode for Ferroelectric Random Access Memory Application
Authors: Sik Kim Woo , Nyung Lee Ji-Wan Kim
Published: October 2002

This paper recommends Pt-oxide for noble electrode of capacitor in advanced ferroelectric random access memory (FRAM). Pt-oxide was deposited by an rf magnetron sputtering system with varying O2 flow ratio [O2/(O2+Ar)] on sol-gel derived Pb(Zr,Ti)O3. The deposition rate of Pt-oxide was higher than that of Pt because of its larger molar volume. However, the deposition rate decreased with further increase in O2 flow ratio due to the oxidation of target surface. After the consideration of resistivity and chemical bonding state of Pt-oxides, 70% of O2 flow ratio was adopted as a deposition condition of Pt-oxide. Pt-oxide/PZT/Pt structure showed fatigue free behavior without degradation of I–V characteristic. These results indicate that Pt-oxide is a promising electrode material for ferroelectric capacitor.
Effects of Magnetic Properties and Layer Thickness on the Readout Performance of Magnetic Amplifying Magneto-Optical System Disks
Authors: Kim Jin-Hong , Hong Ki-Myung , Choi Woo-Suk
Published: October 2002

The effects of magnetic properties of a GdFeCo readout layer and the
thickness of each layer on the readout signal in magnetic amplifying
magneto-optical system (MAMMOS) disks were investigated. The readout
signals were sensitive to the magnetic properties of the readout layer.
However, the readout performance is not strongly dependent on the thickness
of the readout layer, memory layer, and Si3N4 dielectric layer. The optimum
magnetic properties of the readout layer and the thickness of each layer were
obtained.
Silicon Needles Fabricated by Highly Selective Anisotropic Dry Etching and Their Field Emission Current Characteristics
Authors: Kanechika Masakazu , Mitsushima Yasuichi
Published: October 2002

A new process to fabricate a silicon needle, whose tip radius is about 5 nm and aspect ratio is about 7, was developed. The silicon needles were fabricated by highly selective anisotropic dry etching. The etching mask was oxygen precipitation, which was formed by nitrogen ion implantation and the subsequent oxidation. The process is simple enough to be integrated with complementary metal-oxide-semiconductor (CMOS) circuits. The density of the silicon needle can be controlled by adjusting the dose for nitrogen ion implantation. The position of the silicon needle can be controlled by adjusting the position for nitrogen ion implantation, because silicon needles are formed only in the nitrogen ion implantation area. Furthermore, using these silicon needles as micro emitters, a field emission diode was fabricated. The Fowler-Nordheim plot shows that the field around the tip of the silicon needles was highly enhanced.
Anisotropically Etched Si Mold for Solid Polymer Dye Microcavity Laser
Authors: Minoru Sasaki Minoru Sasaki , Yigui Li Yigui Li , Yoshinori Akatu Yoshinori Akatu , Takehiro Fujii Takehiro Fujii , Kazuhiro Hane Kazuhiro Hane
Published: October 2002

A new method for solid polymer dye microcavity laser fabrication is described. The hexagonal prism-shaped cavity is fabricated using a mold of Si (111) wafer. Dry etching is used to form the main shape of the cavity, and subsequent anisotropic etching is applied for a short time to smooth the etched surface. The etchant used is ethylenediamine pyrocatechol and water. From this Si mold, an array of hundreds of microcavity replicas are obtained at once. The lasing from the fabricated cavities is confirmed by sharp peaks in the emission spectrum.
Cantilever Probe Integrated with Light-Emitting Diode, Waveguide, Aperture, and Photodiode for Scanning Near-Field Optical Microscope
Authors: Minoru Sasaki Minoru Sasaki , Kotaro Tanaka Kotaro Tanaka , Kazuhiro Hane Kazuhiro Hane
Published: October 2002

A microfabricated scanning near-field optical microscope (SNOM) probe integrated with a light-emitting diode, waveguide, aperture, and photodiode is described. This probe includes all optical elements necessary for SNOM on the Si cantilever. By using a-Si as the core layer and SiO2 as the cladding layer, the process for fabricating the waveguide is compatible with that for fabricating the photodiode. The light is confirmed to transmit along the waveguide route with the large curvature. The obtained SNOM image shows a spatial resolution better than 200 nm.
Carbon Nanotube-Based Field-Emission Displays for Large-Area and Full-Color Applications
Authors: Lee Nae Sung , Chung Deuk Seok , Kang Jung Ho , Kim Hoon Young , Park Sang Hyun , Jin Yong Wan , Choi Yong Soo , Han In Taek , Park Nam Shin , Yun Min Jae , Jung Jae Eun , Lee Chan Jae , You Jong Hun , Jo Sung Ho , Lee Chun Gyoo , Kim Jong Min
Published: October 2002

Single-wall carbon nanotubes (SWNTs) were applied to electron emitters of field-emission displays (FEDs). Large-area FED devices with SWNT emitters were successfully fabricated in a diode mode using screen printing to demonstrate moving color images. They revealed excellent field-emission characteristics of a threshold electric field of approximately 2 V/µm. We have also investigated triode-type FED structures to achieve a high gray scale and high brightness. It was observed that electron emission from carbon nanotube emitters was controlled by the modulation of gate voltages.
Study of the Multi-Level Reflection Modulation Recording for Phase Change Optical Disks
Authors: Shi Lu Ping , Chong Tow Chong , Tan Pik Kee , Miao Xiang Shui , Ho Jia Jun , Wu Yong Jun
Published: October 2002

Multi-level reflection was obtained on rewritable phase change
optical disks with a static tester using different laser
amplitudes. Different levels of input power amplitude give rise to
different reflection levels. In order to study the mechanism for
forming the multi-level reflection, partial crystallization effect and
size effect were studied. The partial crystallization effect was
studied using differential scanning calorimeter (DSC) measurement and
X-ray diffractometer (XRD) measurement. The size effect was studied by
simulation and measurement. Based on the simulation and experimental
results the combination of size effect and partial crystallization
effect is proposed as the main reason to cause the multi-level
reflection. This model can be used to analyse the writing, erasing,
and overwriting processes of multi-level reflection modulation
recording.
Investigation of Crystallization Behavior of Sputter-Deposited Nitrogen-Doped Amorphous Ge2Sb2Te5 Thin Films
Authors: Hun Seo Hun Seo , Tae-Hee Jeong Tae-Hee Jeong , Jeong-Woo Park Jeong-Woo Park , Cheong Yeon Cheong Yeon , Sang-Jun Kim Sang-Jun Kim , Sang-Youl Kim Sang-Youl Kim
Published: October 2002

The crystallization behavior of nitrogen-doped amorphous Ge2Sb2Te5-(N) phase-change thin films was studied by utilizing differential scanning calorimetry, in situ ellipsometry and in situ transmission electron microscopy. The combined analysis of in situ ellipsometry isotherms of amorphous Ge2Sb2Te5-(N) films and the Johnson-Mehl-Avrami equation revealed that the crystallization process of amorphous Ge2Sb2Te5-(N) films changes depending on the nitrogen content. The crystallization behavior of Ge2Sb2Te5 film revealed a two-step process that includes spherical-nucleation and disc-shaped grain growth. In contrast, nitrogen-doping into
Ge2Sb2Te5 thin films suppresses the second step and the crystallization of
Ge2Sb2Te5-(N) becomes a one-step process that is the primary nucleation process. The number of nucleation sites during the crystallization of amorphous Ge2Sb2Te5-(N) films, increased markedly with the annealing temperature in the spherically shaped nuclei and eventually saturated. The effective crystallinity of
Ge2Sb2Te5-(N) alloy films decreased with the increase in nitrogen content, mainly due to the grain-size refinement.
Super-Resolution Rewritable Optical Disk Having a Mask Layer Composed of Thermo-Chromic Organic Dye
Authors: Hatakeyama Masaru , Ando Toshio , Tsujita Koji , Oishi Kenji , Ueno Ichiro
Published: October 2002

Super-resolution (SR) effects of a thermo-chromic organic dye
mask layer are
investigated for a rewritable disk with a Ag–In–Sb–Te phase-change
recording layer.
Clear SR effects were recognized in both linear and radial directions
in the rewritable
disk, corresponding to a capacity of 10.3 GB in a 120 mm disk. A
carrier-to-noise ratio
over 35 dB was obtained at a short mark length of
0.2 µm. Crescent-shaped marks,
which are typically recognized in high-density magneto-optical (MO)
media, were
observed in the phase-change recording layer. The SR effects mainly
operate on the
reading process, resulting from a large non-linear transmittance
change in the organic dye.
Large Capacity and High-Data-Rate Phase-Change Disks
Authors: Kasami Yutaka , Kuroda Yuji , Seo Katsuhiro , Kawakubo Osamu , Takagawa Shigeki , Ono Masumi , Yamada Masahiro
Published: October 2002

Large-capacity phase-change disks permitting higher data-transfer rates have been
developed for 0.85-numerical-aperture (NA) recording systems. Three methods to improve
the recording data rate were examined. First, the recording layer was sandwiched by
ceramic layers for the purpose of promoting nucleation. Second, signal properties were
evaluated with a disk that had a so-called absorptivity-controlled structure. Third, these two
methods were combined so that they functioned together in one disk. The disk structure was
optimized separately for 640 nm and 407 nm wavelengths. With the disk designed for 640
nm wavelength, a user capacity of 9.2 GB and a user data-transfer rate of 50 Mbps were
obtained. These quantities were 22 GB and 35 Mbps with the disk designed for 407 nm
wavelength. (The disk diameter was 120 mm and the format efficiency
was 80%.)