bluuebunny/crossref_metadata_2025 huggingface dataset:
Monte Carlo Simulation Study of Local Critical Dimension Error on Mask and Wafer
Authors: Ahn Byoung-sup , Park Joon-Soo , Choi Seong-Woon , Sohn Jung-Min
Published: February 2005

Sub-100 nm lithography has been realized recently in the IC industry. The resolution enhancement techniques (RET) and optical proximity effect correction (OPC) require more complicated mask patterns. It is therefore, very important to simulate and calculate mask error enhanced factor (MEEF), and critical dimension (CD) variations on the mask and wafer correctly using optical simulation tool before manufacturing. However, the expectations of MEEF and CD error using the in-house optical simulation tool, Topo, are larger than those of the experimental result. These are caused by many reasons. The ignorance of the vector property of light could be one reason. In case of using higher numerical aperture (NA), the vector property of light, such as polarization, should be taken into account when calculation of printed image on wafer. Also, the ignorance of the local CD error caused by the neighborhood could be another reason. The second issue described above has been studied using the Monte Carlo (MC) method, a commonly used statistical method. We assume that all of the factors follow the normal curve with a certain standard deviation. This assumption is sufficient for studying local CD error by the MC method. When the local CD variation on the mask for the design rule 110 nm is 3 nm in its 3σ, CD variation of approximately 2.0 nm on wafer is expected by the MC method. This result is fairly comparable with experimental one, when the MEEF is about 2.7 locally. We obtain another MEEF value, around 4.1 globally, when the mask CD deviates from the target CD by ±12 nm in 3σ. This study shows that the MC method gives a result close to that of the experimental one greater than 2.5 of MEEF locally.
Resist Outgassing Characteristics in Extreme Ultraviolet Lithography
Authors: Watanabe Takeo , Hamamoto Kazuhiro , Kinoshita Hiroo , Hada Hideo , Komano Hiroshi
Published: February 2005

Extreme ultraviolet (EUV) lithography requires a vacuum environment for exposure. The hydrocarbons outgassing ion species affect the reflectivity of the mask and the imaging mirror under EUV irradiation. Concerning the high-annealing-type chemically amplified (CA) resist based on the polyhydroxy styrene (PHS) resin, it is confirmed that propylene glycol monomethylether (PGME) which is employed as a solvent has the lowest outgassing characteristics under EUV irradiation. Mitigation of the hydrocarbons outgassing species and line edge roughness (LER) requires the main-chain-decomposition-type CA resist. From the outgassing measurement results, the methacrylate base resin can be employed in the resist process in EUV lithography.
Modeling Clear Phase-Mask Materials for Sub-50 nm X-Ray Application
Authors: Malueg Daniel H. , Khan Mumit , Cerrina Franco , Taylor James W.
Published: February 2005

This paper presents a powerful modeling approach to the X-ray exposure operating space of a silicon nitride clear phase-shifter mask to produce sub-50 nm features. By first developing a central composite experimental design, we then used a wavefront modeling toolset to calculate intensity and linewidth responses for each of the response surface cells. Excellent second-order models were fit to the data for each of the responses. Analysis of the response surface data revealed curvature of the response surface for linewidth at the 70% maximum intensity threshold as a function of the absorber wall slope. The effect of the other three factors was more linear, and it was found that: 1) for every 100 nm increase in absorber thickness, the linewidth decreased 1.0 nm 2) for every 1.0 µm increase in gap, the linewidth increased 0.8 nm and 3) for every 1.0 nm increase in critical dimension (CD), the linewidth increased 0.1 nm.
Effect of the Einzel Lens Structure in Microcolumn
Authors: Kim Young Chul , Kim Dae-Wook , Ahn Seungjoon , Choi Sang-Kook , Kim Dae-Yong , Kim Ho Seob
Published: February 2005

Electron beam microcolumn system is thought to be attractive because of its potential applications as a miniaturized electron source and various equipments based on it. Einzel lens is composed of three lens electrodes and used to focus the electron beam. The structure of an Einzel lens has been reported to have a great influence on the final output beam properties. The influence of the lens thickness and the focusing voltage on its operation has been investigated. Simulation analysis was performed with FCM by varying the electrode thickness from 2 to 100 µm and the focusing voltage from 1500 to 2300 V in an accelerating mode. Both probe beam diameter and working distance decrease with the increase of the focusing voltage and the relation between these two variables shows a linear dependency. The result also indicate that both probe beam diameter and working distance decrease with the increase of the thickness of electrode. The change of the electrode thickness from 2 µm to 100 µm show 20%–40% decreasing of the beam diameter. Most of all, Einzel lens composed of thicker lens offers smaller probe beam and more stable operation rather than conventional 2 µm thin lens system. This result suggests that the high performance of as well as easier fabrication can be achieved through optimization of the Einzel lens structure.
Three-Dimensional Proximity Effect Correction for Multilayer Structures in Electron Beam Lithography
Authors: Ogino Kozo , Hoshino Hiromi , Machida Yasuhide , Osawa Morimi , Arimoto Hiroshi , Maruyama Takashi , Kawamura Eiichi
Published: February 2005

Proximity effects in multiwiring layers including heavy-metal materials such as tungsten (W) plug are crucial. In this paper, a novel three-dimensional proximity effect correction method which is based on the simplified electron energy flux (SEEF) model combined with the extended area density map method to multilayer structure is proposed. In this SEEF model, electron energy fluxes transmitted and reflected at each layer are discussed and their maps are reconstructed repeatedly by distributing and gathering electron energy fluxes at each layer. The resultant final map of electron energy flux at the surface layer under the resist contributes as the backscattering energy deposited in the resist. Our new correction method has been confirmed by the experiments to powerfully correct the proximity effects in a 3-layer structure. The screening effect due to the W plug array is first observed and can also be corrected by the proposed method.
5-nm-Order Electron-Beam Lithography for Nanodevice Fabrication
Authors: Yamazaki Kenji , Namatsu Hideo
Published: February 2005

We have developed 5-nm-order electron-beam (EB) lithography with good uniformity within a large main deflection field. The keys are a new electron optics system and a high-resolution resist (hydrogen silsesquioxane). Owing to the high resolution and good uniformity of the EB, the lithography can produce patterns with a minimum linewidth of 5 nm at the center and corners of the 500-µm-square main deflection field. Moreover, we accurately measured the beam diameter using a Si knife edge with Ta visors and thresholds of 50–90%. The measurement results agree well with the lithography results when the effect of secondary electrons is taken into consideration. These results demonstrate that high-precision 5-nm-order lithography has been established.
Control Cell Behavior on Physical Topographical Surface
Authors: Su Wen-Ta , Yang Jung-Yen , Lin Chuan-Ding , Chu I-Ming
Published: February 2005

We studied the influence of the substrate topography substrate on the cell respondence. Topographical cues, independent of biochemistry, generated by the polydimethylsiloxanes (PDMS) substrate may have significant effects on cellular behavior. Mouse bone marrow stromal fibroblasts were examined on grooved substrata of equal groove and ridge width (100 µm, 30 µm depth). The phase contrast light microscopy revealed the attachment and orientation of cells on the materials used and indicated that the fibroblasts prefer to grow to confluent on the top of the ridges. This showed that the topographical surface had a profound effect on cell alignment and migration.
Ge Dot Array Formation Using Small Convex Position Anchors
Authors: Kitayama Daisuke , Yoshizawa Taichi , Suda Yoshiyuki
Published: February 2005

On the basis of our recent results of long Ge migration on Si(001) and the Ge dot formation behavior with which Ge dots form at more stable points such as convex structures at higher growth temperatures on patterned Si(001), we propose a formation method for an artificially sized and positioned Ge dot array, with which Ge migrates and Ge dots form at anchor positions, and the dot size is controlled by the amount of Ge growth. Using this method, we successfully form a Ge dot array using an array of small pyramids as an anchor by Ge growth at a growth temperature of 700°C and a postannealing process for migration at a substrate temperature of 700°C for 30 min. The results indicate that the proposed method with the Ge migration and Ge dot anchoring behavior with a small pyramid anchor is very useful in forming an artificially sized and positioned Ge dot array.
Room Temperature Operation of a Coulomb Blockade Sensor Fabricated by Self-Assembled Gold Nanoparticles using Deoxyribonucleic Acid Hybridization
Authors: Chen Chun-Chi , Tsai Chien-Ying , Ko Fu-Hsiang , Pun Chung-Ching , Chen Hsuen-Li , Chen Ping-Hei
Published: February 2005

Molecules of 3-mercaptopropyltrimethoxysilane react with gold nanoparticles to form a gold monolayer on a silicon dioxide substrate. The 12-mer capture Deoxyribonucleic acid (DNA) self-assembles with the nanometer-sized gold particles. Prior to DNA hybridization, a capture DNA produced via hybridization of the target and probe oligonucleotides is covalently bonded to the gold particles. In addition, the probe oligonucleotide containing a thiol group can self-assemble with additional gold nanoparticles, and multilayered structures are thereby fabricated. The device, assembled only with gold nanoparticles and without DNA immobilization, has no quantum effect conductivity, while a DNA sensor assembled from 4 nm gold nanoparticles and oligonucleotides exhibits Coulomb blockade. The measurement of the tunneling current as a function of applied voltage for the Coulomb blockade DNA sensor is reproducible. Using 14 nm gold nanoparticles instead, the Coulomb blockade for the DNA sensor only occurs at temperatures below 150 K.
Fabrication of a Microbiochemical Reactor with Thick Thermal Isolation Layer and Integrated Pt Heater/Sensor in the Microwell
Authors: Choi Hoon-Sung , Seo Chang-Taeg , Eun Duk-Soo , Shin Jang-Kyoo , Choi Pyung , Lee Jong-Hyun
Published: February 2005

We have fabricated a microbiochemical reactor with integrated heater and sensor in the microwell, which is the unlike conventional micromachined biochemical reactors which have an integrated heater and sensor on the backside of the wafer. In order to pattern heater and sensor inside the well, a thick negative Su-8 photo- resist (PR) was used. As a desirable thermal isolation layer at the bottom of the well, we proposed a thick silicon dioxide layer using porous silicon. The temperature distribution in the well for various heater shapes and the effect of the thermal isolation layer was investigated by simulation. Because of the thick thermal isolation layer and Pt heater in the well, we can expect low power consumption and less heat dissipation to the silicon substrate, which is a good thermal conductor, and real-time sensing of reagent.
Characterization of Bi-Stable Micromechanism Based on Buckle Spring and Electrothermal V-Beam Actuators
Authors: Chen Wen-Chih , Wu Chia-Yu , Lee Chengkuo
Published: February 2005

We present a novel bi-stable microelectromechanical structure driven by a pair of one-directional movable electrothermal V-beam actuators for applications need latch functions, like optical switch and relay. In conjunction with the T-shaped end and buckle spring, the first V-beam actuator set can drive the in-plane moving reflective mirror from transmission state to switching state, while the second V-beam actuator set is able to return the reflective mirror from position of switching state to position of transmission state. Thus the bi-directional motion capability is realized by using a pair of V-beam actuator sets with opposite moving direction. The preliminary results prove its application feasibility.
Field Electron Emission from Inkjet-Printed Carbon Black
Authors: Baba Akiyoshi , Yoshida Tomoya , Matsuzaki Kazunari , Ishida Yuji , Asano Tanemasa
Published: February 2005

We demonstrate the field electron emission from a carbon black dot array prepared by inkjet printing. A commercially available inkjet printer and drawing software were used to pattern the carbon-black-containing ink on the tungsten silicide surface which was deposited on a Si wafer. Field electron emission characteristics were measured using a diode configuration. It was found that oxygen reactive ion etching (RIE) of the printed carbon black is effective for obtaining the field emission. The turn-on voltage was 500 V and an emission current over 100 µA was obtained at a voltage of 1400 V with a 25 µm-wide gap between anode and cathode. It was also found that a rapid increase of the voltage is effective in increasing the emission current and the number of emission sites.
Synchrotron Radiation Effect in the Soft X-ray Region on the Surface Properties of Pyromellitic Dianhydride-Oxydianline Polyimide
Authors: Kato Yuri , Kanda Kazuhiro , Haruyama Yuichi , Matsui Shinji
Published: February 2005

The surface modification of a polyimide (PI) sheet using synchrotron radiation (SR) was carried out. The PI sheet was irradiated to white radiation ranging between 50–1000 eV in a vacuum chamber. The contact angle of the PI surface with a water droplet was found to decrease from 75° to 58° by the SR irradiation. The variation of chemical components of the PI surface was studied using X-ray photoelectron spectroscopy (XPS). The ratio of peak intensity from the O1s orbital to that from the C1s orbital increased remarkably by SR irradiation. The increase of wettability on the PI surface was ascribable to the production of an O-rich surface by SR irradiation in the soft X-ray region.
Polymer Screening Method for Chemically Amplified Electron Beam and X-Ray Resists
Authors: Yamamoto Hiroki , Nakano Atsuro , Okamoto Kazumasa , Kozawa Takahiro , Tagawa Seiichi
Published: February 2005

In the acid generation processes of chemically amplified electron beam and X-ray resists, protons come from not acid generators but base polymers. This means that the selection of base polymers has a great effect on the acid generation efficiency. In this article we describe a convenient method of screening polymers for acid generation. We also showed the difference in acid generation efficiencies among substituted polystyrenes.
Effects of Ester Groups on Proton Generation and Diffusion in Polymethacrylate Matrices
Authors: Nakano Atsuro , Okamoto Kazumasa , Kozawa Takahiro , Tagawa Seiichi
Published: February 2005

The control of acid generation and diffusion is essential for the improvement of resist performance based on the chemical amplification concept. Polymethacrylates are excellent matrices to study resist reaction mechanisms. The dependence of polymer structure on acid generation and diffusion was investigated using polymethacrylate matrices. The ester groups of the polymers strongly affect the yield and diffusion of protons. This suggests that the yield and the diffusion constant of the acid can be controlled in chemically amplified resists based on a polymethacrylate copolymer by changing the composite ratio of the units.
Measurement of Shallow Dopant Profile Using Scanning Capacitance Microscopy
Authors: Goragot W. , Takai M.
Published: February 2005

The shallow dopant profile of a 100-nm-deep n+ layer separated by a 300-nm-wide shallow trench isolation (STI) region has been measured using scanning capacitance microscope (SCM). The conduction type of the sample can be obtained by analyzing the dC/dV phase and amplitude profiles obtained by SCM mesurement, where C and V are capacitance and applied voltage, respectively. The structure and size of STI obtained by SCM measurement were compared with those by scanning electron microscope observation. A two-dimensional (2D) simulation of the sample structure was used to extract the carrier density profile from the dC/dV versus the depth data profile obtained by SCM measurement. The 1D carrier distribution was compared with the carrier simulation profile for reference. From the sample surface down to a depth of 100 nm, the electron density profile was in good agreement with the simulated one. In addition, the depletion layer at and near 100 nm was observed consistently with the simulation profile.
Atomic Force Microscope Cantilever Array for Parallel Lithography of Quantum Devices
Authors: Kakushima Kuniyuki , Watanabe Toshiyuki , Shimamoto Kouji , Gouda Takushi , Ataka Manabu , Mimura Hidenori , Isono Yoshimasa , Hashiguchi Gen , Mihara Yutaka , Fujita Hiroyuki
Published: February 2005

Arrayed atomic force microscope (AFM) cantilevers for parallel scanning probe lithography (SPL) have been fabricated by silicon micromachining. Fabrication is based on three KOH etching steps and local oxidation processes. The curvature radius of the tips is as sharp as 20 nm. A laser beam focused onto the middle probe enables us to observe the wafer for alignment and confirm the patterns after the SPL operation. Parallel SPL on N-octadecyltrimethoxysilane (ODS) self-assembled monolayer (SAM) films is susessfully demonstrated with five probes. Good alignment and homogeneity are obtained with simple operation. Parallel SPL for parallel quantum device fabrications is also reported.
Analysis of Electrical Properties of Grain Boundaries in Polycrystalline Silicon Solar Cell Using Laser Beam Induced Current
Authors: Yagi Toshiki , Nishioka Kensuke , Uraoka Yukiharu , Fuyuki Takashi
Published: February 2005

We have investigated the effect of grain boundaries on a polycrystalline solar cell using laser beam induced current (LBIC). We have successfully evaluated the two-dimensional minority carrier diffusion length, which is one of the most important parameters, in order to fabricate high-efficiency polycrystalline solar cells. Based on the carrier lifetime, the numerical recombination velocity at the grain boundaries was obtained. The change of the recombination velocity by the gettering effect was also clarified. We have confirmed that the recombination velocity is improved by the gettering treatment from 2×104–5×104 cm/s to 3×103–7×103 cm/s.
Control of Axial Resistivity Distribution in Bridgman Silicon Growth
Authors: Wang Jong Hoe , Im Jong-In
Published: February 2005

We propose the simple codoping method for improving the productivity of silicon single-crystal growth by controlling axial specific resistivity distribution. Numerical simulations have been performed to study the transport phenomena of dopant impurities in conventional and proposed Bridgman silicon growth using the finite element method and implicit Euler time integration. It has been demonstrated using mathematical models and by numerical analysis that the axial specific resistivity distribution can be modified in horizontal Bridgman silicon growth and relatively uniform its profile is feasible by the proposed doping method.
Structural and Optical Properties of ZnO Epitaxial Films Grown on Al2O3 (112̄0) Substrates by Metalorganic Chemical Vapor Deposition
Authors: Binh Nguyen Thanh , Zhang Bao-Ping , Liu Cheng-You , Wakatsuki Kazuki , Segawa Yusaburo , Usami Noritaka , Yamada Yasuhiro , Kawasaki Masashi , Koinuma Hideomi
Published: February 2005

ZnO films of different thicknesses were grown on Al2O3 (112̄0) substrates by metalorganic chemical vapor deposition. Characterizations using X-ray diffraction and scanning electron microscopy demonstrated the transition from two-dimensional growth to three-dimensional growth with an increase in film thickness. Photoluminescence spectra revealed the thickness dependence of the exciton peak and a stimulated emission due to exciton-exciton scattering was observed.
Substitutional C Incorporation into Si1-yCy Alloys Using Novel Carbon Source, 1,3-Disilabutane
Authors: Yagi Shuhei , Abe Katsuya , Yamada Akira , Konagai Makoto
Published: February 2005

A new carbon source, 1,3-disilabutane (H3Si-CH2-SiH2-CH3:1,3-DSB), is proposed for use in the growth of epitaxial Si1-y
C
y
films with high C substitutionality. The Si1-y
C
y
films have been deposited by plasma-enhanced chemical vapor deposition (PECVD). The Si1-y
C
y
films grown using C2H2 or SiH2(CH3)2 show a reduction in C substitutionality when total C content is more than 2%, whereas they show a marked improvement in C substitutionality for C contents up to 2.5% using 1,3-DSB as a C source.
Schottky Barrier Height Determination by Capacitance-Voltage Measurement on n-GaN with Exponential Doping Profile
Authors: Kubota Naotaka , Ao Jin-Ping , Kikuta Daigo , Ohno Yasuo
Published: February 2005

A capacitance–voltage (C–V) method was developed to extrapolate the Schottky barrier height on n-GaN with exponential carrier concentration profile. The carrier concentration profile of the unintentionally doped GaN was determined by C–V measurement to be exponential. On the basis of this profile, one-dimensional Poisson's equation was calculated to obtain the relation between bias voltage and depletion width. Schottky barrier height was obtained by fitting the curves of 1/C
2 and V with the experimental one, using the Schottky barrier height itself as a fitting parameter.
Controlling the Intrinsic Josephson Junction Number in a Bi2Sr2CaCu2O8+δMesa
Authors: You Li-Xing , Wu Pei-Heng , Xu Wei-Wei , Ji Zheng-Ming , Kang Lin
Published: February 2005

In fabricating Bi2Sr2CaCu2O8+δintrinsic Josephson junctions in 4-terminal mesa structures, we modify the conventional fabrication process by markedly reducing the etching rates of argon ion milling. As a result, the junction number in a stack can be controlled quite satisfactorily as long as we carefully adjust those factors such as the etching time and the thickness of the evaporated layers. The error in the junction number is within ±1. By additional ion etching if necessary, we can controllably decrease the junction number to a rather small value, and even a single intrinsic Josephson junction can be produced.
Compositional Dependence of X-Ray Absorption Spectra on Magnetic Circular Dichroism and Near-Edge Structure at Co K Edge in La1-xSrxCoO3 (0≤x≤0.6)
Authors: Hanashima Takayasu , Azuhata Satoshi , Yamawaki Kouji , Shimizu Norio , Mori Takeharu , Tanaka Masahiko , Sasaki Satoshi
Published: February 2005

We have studied the effect of Sr doping on the magnetic structure of La1-x
Sr
x
CoO3 (x=0, 0.2, 0.3, 0.4, 0.5 and 0.6) by X-ray magnetic circular dichroism (XMCD) at Co K absorption edges. A negative XMCD peak was clearly observed for pure LaCoO3 at E=7.719 keV within the threshold region of the main edge, suggesting the existence of the intermediate-spin state of Co3+. A positive XMCD peak appeared at E=7.723 keV by Sr substitution of La in LaCoO3 (x≥0.2) in accordance with the low-spin state of Co4+ and X-ray absorption near-edge-structure (XANES) spectra. A negative XMCD peak was also observed at the pre-edge, which can be explained as the hybridization with the neighboring Co4+ in the dipole transition. The dispersion-type XMCD signals at the main edge may be rationalized with the hypothetical double-exchange interaction between Co3+ and Co4+.
Characterization of Micro-Channels Fabricated by In-Water Ablation of Femtosecond Laser Pulses
Authors: Iga Yasunobu , Ishizuka Tomohiko , Watanabe Wataru , Itoh Kazuyoshi , Li Yan , Nishii Junji
Published: February 2005

Femtosecond laser pulses are used to drill high-aspect-ratio microchannels from the rear surface of silica glass, which is in contact with water. The relationship between the diameter of the channel and the incident energy of laser pulses is investigated. The diameter of the channel was varied from 2 µm to 50 µm by increasing the energy. The morphology of the entrance and inner walls of the channels was analyzed by scanning electron microscopy. The capillary phenomena in the dead-end microchannels in contact with water are investigated. The realization of circular three-dimensional channels is demonstrated.
High-Speed Data Position Detection Method Using Template Matching for Hologram Memory
Authors: Motoyama Tomoyuki , Sugiyama Yuichi , Ooue Naoya , Yamamoto Manabu , Endo Masahiro , Tanabe Takaya
Published: February 2005

Two-dimensional digital image reproduction in a hologram memory causes incorrect decoding due to image distortion. In order to correct image distortion, the position coordinates of the four corners of the reproduced image are detected by template matching. However, much position detection processing time is required in this signal processing method. In this study, after having used both parallel processing that combines the marker-dividing approach and marker detection image-dividing approach in the hardware detecting process, and the redundant calculation elimination method and brightness totaling method in the software detection process, it is clarified that an increase in the speed of 260-fold could be obtained as compared with the conventional template matching process.
An Effective Fabrication Method for Producing Color Filters of Liquid Crystal Displays
Authors: Yen Tan-Ching , Tso Pei-Lum
Published: February 2005

An effective process for fabricating color filters (CF) must satisfy three requirements: 1) low-cost material, 2) simple procedures, and 3) high throughput. Several systemic issues affect the conventional CF process, such as the pigment-dispersion method. For high yield and low cost, it is necessary to develop a new fabrication method for CFs which are not affected by these systemic issues. In this paper, an entirely new process for fabricating CFs is introduced. This process, which satisfies the three requirements above, introduces chemical-mechanical polishing techniques to produce CFs for LCDs. Because of the usage of chemical-mechanical polishing techniques, this new CF fabrication method is named the color filter polishing (CFP) method.
Contrast Ratio in Homogeneously Aligned Nematic Liquid Crystal Display Depending on Angle between Polarizer Axis and Optic Axis of a Liquid Crystal
Authors: Song Il Sub , Won Hae Kyung , Kim Do Sung , Soh Hoe-Sub , Kim Woo Yeol , Lee Seung Hee
Published: February 2005

We have studied the contrast ratio of a homogeneously aligned nematic liquid crystal (LC) display as a function of the angle between the polarizer axis and LC director. The results showed that a cell configuration in which a polarizer axis facing a light source coincides with a short LC axis has a better process margin in terms of high contrast ratio than that of the cell coinciding with a long LC axis.
Low-Fire Processing and Dielectric Properties of TiO2 with MnOX–CuO
Authors: Chang Jui-Chuan , Chen You-Fan , Jean Jau-Ho
Published: February 2005

Effects of MnO
x
–CuO (MC) on densification and dielectric properties of TiO2 ceramics have been investigated. The densification temperature of TiO2 is greatly reduced from 1100–1200°C for pure rutile down to 900°C with the presence of >3 wt% MC. This is caused by the liquid phase sintering taking place at the interface between CuO in the MC and rutile during firing. For the samples with 3–20 wt% MC, a high relative sintered density of >95% is obtained at 900°C and the resulting dielectric composites have a dielectric constant and loss at 1 MHz in the range of 80–100 and 0.05–0.2%, respectively.
Monolayer Alignment and Optical Properties of Langmuir–Blodgett CuttbPc Films
Authors: Wada Takahiro , Higo Tomoyuki , Irokawa Katsumi , Kimura Tatsumi , Yamashita Masafumi
Published: February 2005

The molecular alignment of Langmuir–Blodgett (LB) thin films fabricated on clean and Al-coated glass substrates was investigated by X-ray diffraction, atomic force microscopy, Fourier-transform infrared spectroscopy and electric susceptibility measurements. Ultrathin films of tetra-tert-butyl copper-phthalocyanine (CuttbPc) mixed with promoting stearic acid (SA) were deposited on the substrates by the LB method, forming up to 20 monolayers in a layer-by-layer manner. Molecular alignment was observed to begin beyond about 7 layers. The tilt angle of molecules on the substrates was about 49° and the third-order electric susceptibility of the LB films was measured as χ(3): Im χ(3)=-3.86×10-7 esu at a wavelength of 620 nm using a z-scan method.
Characterization of Broadband Dispersion Behaviors of Wedge Waves using Laser Ultrasound Technique
Authors: Yang Che-Hua , Tsai Kwen-Yi
Published: February 2005

In this paper we focus on the experimental observation of the broadband dispersion relation of wedge waves using laser ultrasound technique. The dispersion spectra are measured for an extremely large bandwidth which has not been investigated before. It is found that within a characterized small-wave-number regime, the dispersion behavior is predicted with reasonable accuracy by McKenna's thin-plate theory. Through a transition region towards large wave numbers, the dispersion spectra converge on the Rayleigh wave velocity of the wedge material.
Study of Hyperbolic Heat Conduction Problem in IC Chip
Authors: Chen Han-Taw , Song Jen-Pin , Liu Kuo-Chi
Published: February 2005

The hyperbolic heat conduction equation is applied to investigate the rapid transient heat conduction in IC chip instead of the classical Fourier equation. The present study applies an analytical method and a hybrid numerical scheme of the Laplace transform technique and the control volume method in conjunction with the hyperbolic shape functions to investigate the present problem. For the numerical scheme, the Laplace transform method is used to remove the time-dependent terms in the governing differential equation and the boundary conditions, and then the transformed equations are discretized by the control volume scheme. The analytical solution is obtained from a simple mathematical analysis. In order to evidence the reliability and accuracy of the present results, a comparison between the present numerical results and the analytical solution is made. The results show that the present numerical results do not exhibit numerical oscillations in the vicinity of the jump discontinuity and agree well with the analytic solution. It can also be observed that the time derivative of the heat generation and the relaxation time play the important role in the present problem and the non-Fourier effects are significant only for short times.
Nanometer-Scale Metal Plating Using a Scanning Shear-Force Microscope with an Electrolyte-Filled Micropipette Probe
Authors: Iwata Futoshi , Sumiya Yosuke , Sasaki Akira
Published: February 2005

We describe a novel technique of local metal plating using a scanning probe microscope with a micropipette probe filled with an electrolyte solution. An electrode wire inside the electrolyte-filled micropipette and Si surfaces were employed as the anode and the cathode, respectively. Nanometer-scale Cu dots could be electrochemically deposited on the Si surfaces as the micropipette probe was nearly in contact with the surfaces with application of a dc voltage between the electrode wire and the surfaces. It was possible to control the size of the Cu dots by adjusting the deposition time and voltage. Dot arrays and line patterns were sequentially fabricated as the pipette probe scanned the surfaces while changing the probe-to-surface distance under shear-force control. This technique of local metal plating could allow the fabrication of nanostructures such as nanomachines and nanoelectronics.
Scanning Probe Microscope Tip with Carbon Nanotube Truss
Authors: Akita Seiji , Nakayama Yoshikazu
Published: February 2005

We have fabricated a scanning probe microscope tip with a truss consisting of two nanotubes using a scanning electron microscope manipulator. The tip of the nanotube truss was successfully positioned on the optical axis of a tapered optical fiber used as the base. Force curve measurements for the nanotube truss were also performed using the manipulator to investigate the mechanical strength of the truss. The stiffness of the truss was 3.5 higher than that of the individual nanotube.
p-Xylene Adlayers Formed on Rh(111) and Pt(111) Surfaces in Vacuum
Authors: Inukai Junji , Wakisaka Mitsuru , Itaya Kingo
Published: February 2005

The structures of p-xylene adlayers formed on Rh(111) and Pt(111) in ultrahigh vacuum at room temperature were investigated using low-energy electron diffraction and scanning tunneling microscopy. At a low coverage, p-xylene formed a disordered adlayer structure on Rh(111). At the saturation coverage, a highly ordered c(2√3 ×4)rect monolayer was formed on Rh(111) with the packing density of 0.332 nmol·cm-2. On Pt(111), the same c(2√3 ×4)rect monolayer structure of p-xylene was observed but with a different packing density of 0.310 nmol·cm-2.
Structure and Deposition Mechanism of 10-Undecenoic Acid Self-Assembled Layers on H-Si (111) Surfaces Studied by Atomic Force Microscopy and Fourier-Transform Infrared
Authors: Li Yan Jun , Tero Ryugo , Nagasawa Takayuki , Nagata Toshi , Haruyama Yuichi , Urisu Tsuneo
Published: February 2005

Ten-undecenoic acid self-assembled multilayers were deposited on H-Si(111) surfaces and the surface morphology was investigated by atomic force microscopy (AFM). Namely, we studied the H-Si(111) surface modification of –COOH terminal functional groups. Characteristic islands of almost the same height are observed. From AFM images and transmission IR spectra, it was confirmed that multilayer deposition easily occurs through weak intermolecular interactions such as the Van der Waals force and hydrogen bond interactions. The growth mechanism and film structure were discussed.
Magnetic Field Observation around Current Path by Magnetic Force Microscopy
Authors: Saida Daisuke , Takahashi Takuji
Published: February 2005

The magnetic field around a GaAs/AlGaAs mesa stripe induced by an AC current in the range of 0.3–15.6 µA was observed by magnetic force microscopy (MFM). To confirm the possibility of the vector decomposition of the current-induced magnetic field gradient, we compared the magnetic force signals in the cases of parallel and perpendicular configurations between the MFM cantilever and the current path. In addition, we proposed a novel way of eliminating some effects of electrostatic force, by which a good linearity in the magnetic force signals against the currents was achieved. The spatial resolution of this method was also discussed.
Silicon Tip Cantilevers for Force Microscopy in Water with Resonance of 20 kHz or Above
Authors: Toda Akitoshi , Kitazawa Masashi , Yagi Akira
Published: February 2005

Silicon nitride cantilevers with a silicon probe have been developed for force microscopy of soft samples in water. The cantilevers were soft with a small spring constant of from 0.05 to 0.11 N/m and some showed resonance of 20 kHz or higher in water. The typical dimensions of a cantilever were 40 µm ×15 µm ×0.19 µm. Autofluorescent light emissions from the resulting cantilever and probe were studied. Autofluorescence of the silicon nitride cantilever was smaller than that of a conventional silicon nitride cantilever. Autofluorescence of the silicon probe was small and of negligible intensity for fluorescence optical microscopy. The cantilever probe less disturbs fluorescence optical microscopy than conventional soft cantilever probes.
Detection and Characterization of Stress-Induced Defects in Gate SiO2 Films by Conductive Atomic Force Microscopy
Authors: Watanabe Yukihiko , Seko Akiyoshi , Kondo Hiroki , Sakai Akira , Zaima Shigeaki , Yasuda Yukio
Published: February 2005

We have demonstrated the detection of nanometer-scale current-leakage sites in electrically stressed gate SiO2 films using a conductive atomic force microscope (C-AFM). Prior to C-AFM observations, the gate SiO2 films in metal-oxide-semiconductor capacitors were subjected to constant-current Fowler-Nordheim (FN) stress. Details of image contrasts and the relationship between the surface topography and the current image of the SiO2 films were examined. Two types of contrast were clearly observed in the current image: a sharp bright spot reflecting local current leakage were caused by hole trapping at stress-induced defects and a fuzzy bright contrasts originating from the SiO2 thickness fluctuation. The dependence of C-AFM images on the electron injection direction during FN stress application and the SiO2 film thickness clearly reveals that the stress-induced defects are distributed in the region within 2.6 nm from the SiO2/Si substrate interface.
Behavior of Local Current Leakage in Stressed Gate SiO2 Films Analyzed by Conductive Atomic Force Microscopy
Authors: Seko Akiyoshi , Watanabe Yukihiko , Kondo Hiroki , Sakai Akira , Zaima Shigeaki , Yasuda Yukio
Published: February 2005

We studied local leakage currents induced in stressed gate SiO2 films and their time dependence by conductive atomic force microscopy (C-AFM). The current-voltage characteristics of the leakage currents detected in the C-AFM observations indicate Fowler-Nordheim tunneling currents enhanced by holes trapped in the stressed SiO2 films. By repeated C-AFM observations at the same area, it was found that individual spot currents decrease at different rates. This result indicates hole detrapping with different time constants from the stress-induced defects that have different features.
Integrated Thermal and Optical Analyses of Phase-Change Optical Disk
Authors: Li J. M. , Shi L. P. , Miao X. S. , Lim K. G. , Yang H. X. , Chong T. C.
Published: February 2005

An integrated analysis system based on thin film optics, thermal transfer and electromagnetics is developed. Thermal conductivity and generated heat are discussed for mark formation. The simulations of multilayer calorific sources and multibeam heating sources using the finite element method (FEM) are investigated. The readout of nanometer-scaled marks based on computational electromagnetics using the finite-difference time-domain (FDTD) analysis is discussed. The real marks captured with microscopes can be analyzed using this integrated analysis system combined with digital image technology. Material models in the electromagnetic vector method are discussed with reference to different layers of disk. It provides a powerful tool for structure design and failure analysis of phase-change optical disks.
Selective-Area Micropatterning of Liquid-Phase Epitaxy-Grown Iron Garnet Films
Authors: Park Jae-Hyuk , Cho Jae-kyeong , Nishimura Kazuhiro , Uchida Hironaga , Inoue Mitsuteru
Published: February 2005

We investigated selective-area micropatterning of iron garnet film grown by liquid-phase epitaxy (LPE). This method of producing a flat-surface structure overcomes the disadvantages of geometrical grooves, which are formed by wet or dry etching, with a limited resolution due to underetching and nonplanar structure. Moreover, patterned iron garnet films grown by selective-area LPE have better single-crystal properties than films grown by selective-area sputter epitaxy deposition. Thus, this method offers new possibilities for the fabrication of integrated magnetooptic light switch arrays, magnetic waveguides and other magnetooptic devices.
Autoadjusting the Photodetector in an Optical Head System for Optimum Focus
Authors: Wang Shyh-Jier , Lin Shir-Kuan
Published: February 2005

In the assembly of an optical head system, it is required to mount the photodetector integrated chip (PDIC) in the correct position so that the astigmatism phenomenon can be achieved. The conventional means of adjustment requires an experienced engineer to shift the PDIC in the three dimension (3D) space until the S-word profile is obtained. This paper proposes an automatic method for replacing an experienced engineer, which can be formulated as an optimization problem with parameters trained by a neural network method. During the training process, a convex cost function of the 3D position is established and the minimum of this function indicates the correct position of the PDIC. In the mounting stage, the steepest descent method is then applied to search for the optimum of the trained function, so that the PDIC is automatically mounted at the optimal position.
Effect of Thermal Deformation of Optical Pick-up on the Optical Performance
Authors: Kim Hongmin , Cho Sunghoon , Kim Young-Joo , Kang Shinill
Published: February 2005

The effect of thermal deformation of optical pick-up due to laser diode (LD) and LD driving IC on the optical performance of digital versatile disk (DVD) optical system was analyzed using the finite element analysis with initial surface residual stress conditions, and results were compared with the measured results with holographic interferometry. Ray tracing was performed using the deformed configuration of optical system.
Signal Qualification Method for Partial-Response Maximum-Likelihood Read/Write Channel
Authors: Miyashita Harumitsu , Nakajima Takeshi , Kimura Naohiro , Hino Yasumori , Ishibashi Hiromichi
Published: February 2005

The partial-response maximum-likelihood (PRML) signal processing technique is effective for high-density recording media. However, there are few omit evaluation methods for qualifying the played-back signal using a simple measurement tool such as a jitter meter. We propose a simpler PRML qualification method, the so-called maximum-likelihood sequence error (MLSE) detection method. In this paper, we show the validity of the new method for dual-layer Blu-ray Disc read channel and, furthermore, show the method for optimizing the write channel.
Performance Characteristics of a 32 mm Small Form-Factor Optical Disc and Drive
Authors: Blankenbeckler David L. , Davies David H. , Dunford William W. A. , Hamer Bernard W. Bell Jr. and Rene H.
Published: February 2005

Experimental data obtained from testing the DataPlay 32 mm disc and drive are presented. Of particular interest, due to the unique rotary tilt arm actuator and front surface head/media architecture is the data concerning shock, vibration, and temperature and humidity stress environments. Results demonstrate that the DataPlay optical drive and media are sufficiently robust for use in portable consumer electronics devices.
Write-Once Volumetric Optical Disk Using Transparent Recording Material with an Optical Switching Layer
Authors: Wu Fung-Hsu , Shieh Han-Ping D. , Milster Tom D. , Huang Der-Ray
Published: February 2005

A volumetric optical disk having multiple transparent films with optical switching layers is proposed as a recordable medium to increase the number of recording layers. In the disk, an optical switching layer is adopted to reduce laser energy decay and increase recording sensitivity for reading and recording, respectively. A well-defined deformation area (mark) with submicron to nanometric dimensions can be yielded precisely on the transparent films by a focused laser beam. The peak writing power of 7 mW for a four-layer recordable medium, fabricated by molding and spin bonding techniques, was demonstrated experimentally as an example. The proposed volumetric disk can achieve a higher recording capacity by using conventional optical pickup units.
Super-Resolution Optical Disc with High Readout Stability Using a Zinc Oxide Thin Film
Authors: Yamamoto Masaki , Mori Go , Tajima Hideharu , Takamori Nobuyuki , Takahashi Akira
Published: February 2005

We report a new super-resolution read-only-memory (ROM) disc with high readout stability using a zinc oxide (ZnO) thin film. A ZnO film utilized in our experiment showed a change in optical constant depending on temperature. By applying this characteristic to a ROM disc, we obtained a linear bit density two times higher than that of conventional ROM discs in our experimental optical pickup system with a 408-nm-wavelength laser and a 0.65-numerical-aperture (NA) objective lens. The readout stability was improved by employing a Si film. A high readout cyclability of more than 1.0×105 was obtained. Moreover, the super-resolution readout function was confirmed in another optical pickup system with a 408-nm-wavelength laser and a 0.85-NA objective lens.
Design of Dye Concentrations in Azobenzene-Containing Polymer films for Volume Holographic Storage
Authors: Minabe Jiro , Maruyama Tatsuya , Yasuda Shin , Kawano Katsunori , Hayashi Kazuhiro , Ogasawara Yasuhiro
Published: February 2005

Diffraction efficiencies of holograms in thick azo polymer films were improved by designing optical densities of the films. A nonphotosensitive polymer was used as a binder for controlling the dye concentrations. We fabricated 250-µm-thick films by changing the concentrations. While the optically induced birefringence decreased with decreasing concentration, reduction of absorption loss of the reading beam increased the diffraction efficiency. Thus, owing to the competition between the decrease in birefringence and the increase in efficiency, there exist appropriate concentrations for improving both sensitivity and magnitude of the diffraction efficiency. Consequently, the diffraction efficiency reached 25% without degradation of the sensitivity. We also demonstrated holographic multiplexing using the film. A set of 20 data pages (66 kbits per page) was successfully multiplexed and retrieved with a low bit-error rate of 1.3×10-3. The use of an error correction coding would allow error-free recovery of the data pages.
Irreversible Optical Properties of AgOx Mask Layer with Temperature for Super-Resolution Near-Field Structure Application Investigated by in situ, ex situ Ellipsometry
Authors: Li Xuezhe , Kim Sang Jun , An Sung Hyuck , Kim Sang Youl
Published: February 2005

The optical properties of AgO
x
thin films used as mask layers for a super-resolution near-field structure (super-RENS) were determined by in situ and ex situ ellipsometries and UV/VIS spectrometry. Irreversible changes of optical properties of AgO
x
thin films with temperature were also investigated.
A 11–177 Mbps Recordable Digital Versatile Disc (1–16× DVD-R) Using a New Dye
Authors: Kubo Hiroshi , Shibata Michihiro , Hashimoto Hirokazu , Morishima Shin-ichi , Akiba Masaharu , Inagaki Yoshio
Published: February 2005

The possibility of 11 to 177 Mbps (1× to 16×) speed recording was confirmed by the investigation of the recordable digital versatile disc (DVD-R) using a new oxonol dye. Low jitter and a high aperture ratio (AR) even after high-speed recording are attributed to the unique thermal decomposition behavior of the dye, i.e., its low decomposition temperature, small heat generation and well defined void generation. The dye neither contains toxic heavy metals nor corrodes a pure silver reflective layer.
Liquid Immersion Deep-UV Optical Disc Mastering for Blu-ray Disc Read-Only Memory
Authors: Neijzen Jaap H. M. , Meinders Erwin R. , Santen Helmar van
Published: February 2005

The liquid immersion mastering technique has been successfully applied to the mastering of read-only memory (ROM) discs for the Blu-ray disc (BD) system. Replicated discs with a density corresponding to 25 GB in a single layer on a 12 cm disc showed a bottom jitter of less than 5%. Results concerning process latitude and disc uniformity are presented. A full-format 25 GB ROM disc containing over 2 h of high-definition video content has been mastered according to the BD target specification. The results obtained for a reduced channel bit length show the potential of liquid immersion mastering for densities beyond 31 GB per layer.