bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement in Step Coverage of Pb(Zr,Ti)O3 Thin Films Deposited by Liquid Delivery Metalorganic Chemical Vapor Deposition
Authors: Otani Yohei , Abe Norikazu , Miyake Masato , Okamura Soichiro , Shiosaki Tadashi
Published: September 2005

Ferroelectric Pb(Zr,Ti)O3 (PZT) thin films were deposited on trenched SiO2/Si substrates at various substrate temperatures by liquid delivery metalorganic chemical vapor deposition (MOCVD) using Pb(DPM)2, Zr(DIBM)4 and Ti(OiPr)2(DPM)2 as precursors. Their step coverage increased from 38 to 80%, while their deposition rate decreased with decreasing the substrate temperature from 600 to 400°C. In the deposition on planar Pt/Ti/SiO2/Si substrates, the as-grown PZT films deposited under the substrate temperature of 450°C were confirmed to be amorphous; they crystallized into perovskite PZT single phase and showed ferroelectric properties after post annealing at 600°C in air for 15 min. From these results, we concluded that the combination of low-temperature deposition and post annealing is effective in improving the step coverage of PZT thin films deposited by liquid delivery MOCVD although composition control is severe in such a case because the self-regulation of lead atoms is not realized at low temperatures.
Self-Organization Process of Secondary Crystal Nodules from Individual Nuclei in Electrodeposition
Authors: Asanuma Miki , Yamada Akifumi , Aogaki Ryoichi
Published: September 2005

Using nonequilibrium fluctuations in electrodeposition, the self-organization process of secondary crystal nodules from individual nuclei was examined. As a result, it was concluded that electrodeposition can be described by two types of fluctuation, i.e., symmetrical and asymmetrical fluctuations; the former yields three-dimensional (3D) nuclei, whereas the latter yields two-dimensional (2D) nuclei that determine the spatial distribution of the 3D nuclei. The complex self-organization of these two types of nuclei leads to the aggregation of each 3D nucleus. In the present paper, first, the instability of these fluctuations was discussed. Then, it was shown that asymmetrical fluctuations control the total reaction rate, and lead to nucleation currents in silver nucleation. Finally, the crystal morphology yielded by the symmetrical and asymmetrical fluctuations was visualized by computer calculation, and the aggregation process of 3D nuclei to secondary nodules was examined.
Optical Properties of Metal-Oxide Films in Super-RENS
Authors: Liu Qian , Fukaya Toshio , Tominaga Junji , Iwanabe Yasuhiko , Shima Takayuki
Published: September 2005

The property of the optical transmittance and reflectance induced by structural changes in AgO
x
, PtO
x
and PdO
x
thin films, which are materials of key layer in superresolution near-field structure (super-RENS) optical disk, is investigated by Z-scan measurements and microscopic observations. The light intensity features of the transmittance and reflectance are clarified. Laser-irradiated decomposition of the noble metal oxides in the films and their decomposition thresholds are examined. The optical properties of the films result from bubbles induced by the chemical decomposition of the oxides and the metallic nanoparticles dispersed in the bubbles. The light-induced thermal features, reversible and irreversible properties, optical responses corresponding to the decomposition of the oxides, the influence on readout stability, and the signal intensity of the metal-oxide (MeO) super-RENS disks are also discussed for MeO films.
Photocatalytic Activity of Titanium Dioxide Coated with Apatite
Authors: Ichimura Shuji , Ebisu Hiroshi , Nonami Toru , Kato Kazumi
Published: September 2005

Titanium dioxide coated with apatite (AP–TiO2) was produced by stirring commercial TiO2 (ST-01) into a simulated body fluid (SBF). Radicals generated at the surface of photoaccelerated ST-01 and AP–TiO2 were analyzed by electron spin resonance (ESR) spectroscopy in a spin-trapping experiment. During photoirradiation for 0–60 s, photogenerated [DMPO–OH] for ST-01 and AP–TiO2 increased with irradiation time. On the other hand, during photoirradiation for 60–500 s, [DMPO–OH] for ST-01 decreased but [DMPO–OH] for AP–TiO2 did not. On the basis of these phenomena, it was suggested that DMPO trapped photogenerated OH• and was converted into DMPO–OH which then decomposed to H2O2 upon further photoirradiation. The decomposition of DMPO–OH and generation of H2O2 were prevented by apatite at the surface of TiO2. Additionally, the adsorptive nature of AP–TiO2 for methylene blue and photocatalytic activity for bleaching were improved by apatite at the surface of TiO2.
Development of Multi Faraday Cup Assembly for Ion Beam Measurements from a Low Energy Plasma Focus Device
Authors: Mohanty Smruti Ranjan , Bhuyan Heman , Neog Nirod Kumar , Rout Rabindra Kumar , Hotta Eiki
Published: September 2005

A multiple Faraday cup assembly has been developed for measuring pulsed ion beam of a low energy plasma focus device. The Faraday cups operating in biased ion collector mode have nanosecond response and these have been used to determine the energy spectrum and flux of fast nitrogen ion beam emerging out of the pinched plasma column. The design feature that makes our Faraday cups unique is that they can register ion energy of higher kinetic value (∼hundreds of keV) as well as lower kinetic value (∼keV). It has been possible to register the ion energy upto a lower kinetic energy threshold of ∼5 keV which is a value much lower than that obtained in any previous works. The correlation of the ion beam flux with filling gas pressure is also reported. Angular distribution of ion measurement reveals a highly anisotropic emission indicating an ion dip at the electrode axis.
Effect of Plasma Electrode Position of RIKEN 18 GHz Electron Cyclotron Resonance Ion Source on Beam Intensity of Highly Charged Ar Ions
Authors: Higurashi Yoshihide , Nakagawa Takahide , Kidera Masanori , Aihara Toshimitsu , Kase Masayuki , Yano Yasushige
Published: September 2005

We measured the beam intensity of Ar11+,12+ ions from the RIKEN 18 GHz electron cyclotron resonance ion source (ECRIS) as a function of the plasma electrode position. Beam intensity is strongly dependent on the electrode position. Beam intensity increases when the electrode is set at ∼8 mm from the edge of the hexapole magnet.
Synthesis and Properties of 1-Methyl-4-{2-[4-(dimethylamino)phenyl]ethenyl}pyridinium p-Toluenesulfonate Derivatives with Isomorphous Crystal Structure
Authors: Glavcheva Zornitza , Umezawa Hirohito , Mineno Yoshihiro , Odani Toru , Okada Shuji , Ikeda Satoshi , Taniuchi Tetsuo , Nakanishi Hachiro
Published: September 2005

DAST, 1-methyl-4-{2-[4-(dimethylamino)phenyl]ethenyl}pyridinium p-toluenesulfonate, has been recently reported as an efficient THz-wave generator by difference frequency generation. In this study, two DAST derivatives, i.e., perdeuterated DAST (DAST-d
26) and DASC with p-chlorobenzenesulfonate replacing the p-toluenesulfonate of DAST, were investigated as model compounds to analyze the THz-wave intensity variation of DAST as a function of frequency. X-ray crystallographic analyses of DAST-d
26 and DASC were carried out for the first time, and it was found that both compounds gave crystals isomorphous with DAST. Their basic properties were also investigated.
Slip-Free Driving Method for Nonresonant Piezoelectric Actuator
Authors: Endo Taishi , Egashira Yoshiya , Furukawa Hiroyuki , Hashiguchi Hiroyuki , Kosaka Kouji , Watanabe Masayuki , Miyata Noboru , Moriyama Shirou , Sasaki Syunichi , Nakada Akira , Ohmi Tadahiro , Kubota Hiroshi
Published: September 2005

It is generally considered that in the ultrasonic motor the motion always slips and scratches. The nonresonant ultrasonic motor (NRUSM) expected for future precision stage systems should, however, overcome the difficulties of the wear of friction materials, which has been encountered in the use of conventional ultrasonic motors. The wear occurs by slipping and may be reduced by material selection. In this paper, we focus on the control method at actuation to prevent slipping. The advantages of NRUSM in the ability to control the drive frequency as well as the drive amplitude are shown, and this is effective in reducing wear and obtaining long-term stability. The drive frequency condition for no slippage under sinusoidal waveforms was calculated. The experimental results correspond to the theoretical calculated drive frequency. Because the resultant values of the frequencies are low for practical applications, we present the slip-free actuation method of using the new actuator's driving waveform and time chart in order to drive the stage at constant accelerated motion.
Fast and Accurate Technique for Determination of Moisture Content in Oil Palm Fruits using Open-Ended Coaxial Sensor
Authors: Abbas Zulkifly , Yeow You Kok , Shaari Abdul Halim , Zakaria Azmi , Hassan Jumiah , Khalid Kaida , Saion Elias
Published: September 2005

A simple, fast and accurate technique employing an open-ended coaxial sensor for the determination of the moisture content in oil palm fruit is presented. For this technique, a calibration equation has been developed based on the relationship between the measured moisture content obtained by the oven drying method and the phase of the reflection coefficient of the sensor for 21 fruits. The moisture content predicted by the sensor was in good agreement with that obtained using the standard oven drying method within ±5% accuracy when tested on 145 different fruits samples.
Carbon Nanotube Growth Technologies Using Tantalum Barrier Layer for Future ULSIs with Cu/Low-k Interconnect Processes
Authors: Horibe Masahiro , Nihei Mizuhisa , Kondo Daiyu , Kawabata Akio , Awano Yuji
Published: September 2005

We succeeded in developing carbon nanotube (CNT) vias specifically adapted for the copper interconnect process used in ultra large-scale integrated circuits. The CNTs were grown selectively on titanium films using Co catalyst films. The use of tantalum enabled CNTs to be grown on Cu lines and prevented any increase in the sheet resistance of the Cu lines. A Cu wire/CNT via/Cu wire structure was fabricated and low resistance of the via was demonstrated. In addition, tests showed that a high current density of about 106 A/cm2 flowed into the CNT via for 125 hours.
Kondo Effect of Co Adatoms on Ag Monolayers on Noble Metal Surfaces
Authors: Schneider M. Alexander , Wahl Peter , Diekhöner Lars , Vitali Lucia , Wittich Gero , Kern Klaus
Published: September 2005

The Kondo temperature T

K
of single Co adatoms on monolayers of Ag on Cu and Au(111) is determined using Scanning Tunneling Spectroscopy. T

K
of Co on a single monolayer of Ag on either substrate is essentially the same as that of Co on a homogenous Ag(111) crystal. Besides giving strong evidence that the interaction of surface Kondo impurities with the substrate is very local in nature the data show that the energy scale of the many-electron Kondo state is insensitive to the properties of surface states and to the energetic position of the projected bulk band edges. We demonstrate that the trend of the Kondo temperature of Co adatoms is correlated to the impurity's d-band shift as obtained from the Hammer and Nørskovs model of reactivity neglecting many-body effects.
Scanning Tunneling Microscopy and Spectroscopy of Phthalocyanine Molecules on Metal Surfaces
Authors: Takada Masaki , Tada Hirokazu
Published: September 2005

We studied the electronic structure of cobalt-phthalocyanine (CoPc) molecules on Au(111) and Cu(100) surfaces by scanning tunneling microscopy and spectroscopy at 5 K. In the differential conductance (dI/dV) spectra, there were some peaks related to the highest occupied molecular orbital (HOMO), the lowest unoccupied MO (LUMO) and thed-orbitals of the Co atom. CoPc molecules on the Cu(100) surface had new electronic states between the peaks related to HOMO and LUMO, while those on the Au(111) surface did not show additional peaks. A dI/dVimage indicated that the new states were generated by the hybridization between the LUMO of molecules and the electronic states of the Cu(100) surface.
ab initio Calculation of Capacitance of Nanostructures
Authors: Watanabe Kazuyuki , Watanabe Satoshi , Tanaka Michiko , Nakaoka Noriyuki
Published: September 2005

We report our recent results on the electrochemical capacitances of nanostructures under various conditions investigated by new ab initio methods based on the density-functional theory. As the gap of two semi-infinite electrodes decreases, capacitance shows a crossover from classical to quantum behaviors caused by electron tunneling that is highly sensitive to the atomic geometry of electrode surfaces. The calculated capacitances of two electrodes of various nanostructures in the case without electron tunneling are in good agreement with the experimental observations. The atomic geometry and electronic states of clusters and fullerenes are found to faithfully reflect the self-capacitances of the electrodes. The results enable us to emphasize the quantum nature of capacitance on the nanoscale.
Nanometer-scale Mechanical/Structural Properties of Molybdenum Dithiocarbamate and Zinc Dialkylsithiophosphate Tribofilms and Friction Reduction Mechanism
Authors: Ye Jiping , Araki Sawa , Kano Makoto , Yasuda Yoshiteru
Published: September 2005

Nanometer-scale differences in mechanical and structural properties between the molybdenum- dithiocarbamate/zinc-dialkylsithiophosphate (MoDTC/ZDDP) tribofilm and ZDDP tribofilm were successfully evaluated by using atomic force microscopic phase-image techniques, Auger electron spectroscopy and X-ray photo spectroscopy. It is well known that the MoDTC/ZDDP tribofilm exhibits markedly lower friction behavior than the ZDDP tribofilm. To elucidate the mechanism of friction reduction originating from the MoDTC additive, attention was focused on property differences in the surface area in particular, from the uppermost surface to an underlying region of less than 10 nm in depth. It was found that the friction reduction due to the MoDTC/ZDDP additives originates from an inner skin layer formed by MoS2 nanostrips just below the surface. The MoS2 nanostrips were oriented in the sliding direction, had low yield strength and acted as a solid lubricant in lowering the friction coefficient of the MoDTC/ZDDP tribofilm.
Kelvin Probe Force Microscopy Study of Conjugated Polymer/Fullerene Organic Solar Cells
Authors: Glatzel Thilo , Hoppe Harald , Sariciftci Niyazi S. , Lux-Steiner Martha Ch. , Komiyama Masaharu
Published: September 2005

We conducted a comprehensive Kelvin probe force microscopy (KPFM) study of the “classical” organic solar cell system consisting of the MDMO-PPV:PCBM blend. The KPFM method yields detailed information of topography and local work function on the nanometer scale. Experiments were performed either in the dark or under laser illumination to extract locally resolved surface photovoltage. We identified distinct differences in energetics on the surface of chlorobenzene- and toluene-cast blend films. The electronic and structural behavior of the toluene-cast blend films were analyzed in relation to illumination and substrate temperature. Together with previous studies we were able to interpret the KPFM results and draw some conclusions regarding the correlation between the nanostructural properties and photovoltaic performance of organic solar cells.
Long-Ranged and Short-Ranged Electrostatic Interaction Between Modified Silicon Surfaces and Recombinant Ferritin Molecules
Authors: Hayashi Tomohiro , Hara Masahiko
Published: September 2005

Atomic force microscopy (AFM) was employed to probe the interaction between recombinant ferritin molecules immobilized on an AFM tip and surface-modified silicon substrates. Force-distance curve profiles demonstrated for the first time the controllability of long-ranged ferritin-substrate interactions and the amount of ferritin molecules adsorbed on a substrate by modifying the amino acid sequence in the N-terminal domains. In addition, we proposed that the decoration of substrate surface with self-assembled monolayers (SAMs) also helped in controlling the ferritin-substrate interaction and the resulting adsorption amount. Our important finding is that the amount of ferritin adsorbed cannot be predicted simply from the zeta potentials of a ferritin molecule and substrate, and that the flexibility of the surface polar groups on a Si substrate is an important factor that governs the amount of the adsorption. Based on the analysis of force-distance profiles, we discuss what kind of force dominates the long-ranged and short-ranged interactions between ferritin and silicon substrates. These provide insights and lead to a deeper understanding of the factors to govern the adsorption of ferritins onto solid substrates.
Self-Assembled Monolayers of Alkanethiol and Fluoroalkanethiol Investigated by Noncontact Atomic Force Microscopy
Authors: Ichii Takashi , Urabe Masashi , Fukuma Takeshi , Kobayashi Kei , Matsushige Kazumi , Yamada Hirofumi
Published: September 2005

We investigated single-component fluoroalkanethiol self-assembled monolayers (SAMs) and phase-separated SAMs composed of alkanethiol and fluoroalkanethiol by noncontact atomic force microscopy (NC-AFM). We obtained molecularly resolved images of the single-component fluoroalkanethiol SAMs. Their molecular film structures were compared with those of alkanethiol SAMs. In addition, energy dissipation and surface potential (SP) images were obtained for the phase-separated SAMs. These images clearly showed the feature of phase separation. The contrast in energy dissipation images was discussed in terms of their structural rigidity. The molecular dipole moments were calculated using a MOPAC program and the theoretical SP difference was compared with the experimental results.
Electronic Conduction through Single Molecule of New π-Conjugated System Measured by Scanning Tunneling Microscopy
Authors: Ishizuka Kenichi , Suzuki Masaaki , Fujii Shintaro , Akiba Uichi , Takayama Yuuki , Sato Fumie , Fujihira Masamichi
Published: September 2005

In recent years, π-conjugated organic compounds have become a widely investigated class of advanced materials as they exhibit a variety of interesting electronic properties. One of the most attractive properties is their small highest occupied molecular orbital-lowest unoccupied molecular orbital gap, which results in the very high charge transport efficiency of the π-conjugated compounds as compared with that of saturated compounds. A new π-conjugated compound was synthesized by a recently developed method. We investigated electronic conduction through an isolated single molecule of the π-conjugated compound by scanning tunneling microscopy (STM) and self-assembly techniques.
Tunneling Spectroscopy Analysis of Hexachloro-Fluorescein Phosphoramidite Fluorescent Dye Attached to Deoxyribonucleic Acid
Authors: Kawahara Toshio , Takahashi Takuya , Tanaka Hiroyuki , Kawai Tomoji
Published: September 2005

Scanning tunneling microscopy (STM) was used to observe hexachloro-fluorescein phosphoramidite (HEX) attached to single-stranded deoxyribonucleic acid (ssDNA) with molecular resolution. Scanning tunneling spectroscopy (STS) was also used to study the electric properties of HEX in single-molecular spectroscopy. In the STM topographic images, the bright HEX molecule and each base subunit of DNA could be clearly observed, just as with fluorescein isothiocyanate (FITC) attached to ssDNA. In contrast to FITC, HEX molecules usually did not show a clear peak in their tunneling spectra. Two types of HEX molecules seemed to have different apparent heights, and only the HEX with the larger height in topographic images showed a peak at +0.6 V. The conformation of the HEX seems to affect the measured spectra. Thus, we obtained another molecule marker in addition to FITC with different spectral features for STM.
Direct Observation of Conformational Isomers of (CH3S)2 Molecules on Cu (111)
Authors: Ohara Michiaki , Kim Yousoo , Kawai Maki
Published: September 2005

Scanning tunneling microscope (STM) images of isolated molecules of dimethyl disulfide, (CH3S)2, adsorbed on a Cu (111) surface were successfully obtained at a sample temperature of 4.7 K. A (CH3S)2 molecule appears as an elliptic protrusion in the STM images. The STM images of (CH3S)2 molecules revealed that the molecules have a total of six equivalent adsorption orientations on Cu (111), which are given by the combination of three equivalent adsorption sites and two conformational isomers for each adsorption site.
Atomic Force Microscopy on Imogolite, Aluminosilicate Nanotube, Adsorbed on Au(111) Surface
Authors: Ohrai Yoshihisa , Gozu Tomoaki , Yoshida Shoji , Takeuchi Osamu , Iijima Sumio , Shigekawa Hidemi
Published: September 2005

Natural imogolite and its adsorption structure were studied on a Au (111) substrate by tapping- and non contact (NC)-mode atomic force microscopy (AFM). When the length of the imogolite tubes was over 2–3 micrometers, a tangled structure was observed. In contrast, when the length was shortened to 1 µm, a layered structure consisting of well-ordered imogolite tubes was formed. When the length was shortened further, imogolite tubes dispersed on the substrate. These results indicate that the adsorption structure is influenced by the interaction between imogolite tubes depending on their length, suggesting the controllability of the structures of this material. The structure of a single imogolite tube itself is also discussed.
Nanorheological Analysis of Polymer Surfaces by Atomic Force Microscopy
Authors: Nukaga Hideyuki , Fujinami So , Watabe Hiroyuki , Nakajima Ken , Nishi Toshio
Published: September 2005

Surfaces of polymer blends were investigated using atomic force microscopy (AFM) to study their nanomechanical properties (nanorheology). We were particularly interested in information obtained from force-distance curve methods on rubbery or melt state samples. In order to realize clear comparison, a rubbery sample, polyisobutylene (PIB), was blended with a glassy-state sample, polystyrene (PS). When PS/PIB blends were observed in contact-mode operation, PIB-rich phases appeared as depressions. However, this was an artifact caused by the very low elastic modulus of PIB. By analyzing the force-distance curve, sample deformation by the force exerted was estimated together with real height free from sample deformation. Thus, if force-distance curve measurements are performed on every point of the sample (force-volume measurements), we can reconstruct a “real height image” and a “sample deformation image.” The apparent depressions became almost flat in the “real height image” by this analysis. With further analysis using Hertz theory, an elastic modulus image of the sample was also obtained, which correlated more closely with the “real height image” than with the“apparent height image.”
Connection of Herringbone Ridges on Reconstructed Au(111) Surfaces Observed by Scanning Tunneling Microscopy
Authors: Oka Hirofumi , Sueoka Kazuhisa
Published: September 2005

After postannealed at 950 K, Au films deposited on MgO(001) substrates exhibit (22×√3) reconstructed (111) surfaces. A scanning tunneling microscopy study reveals that a new structure in which one herringbone ridge connects with another exists on the Au(111) film surfaces. Furthermore, a `steplike defect', which appears locally and exhibits a step height lower than a monatomic step, exists near the herringbone ridge connection. The origins of the connection of the herringbone ridge and the steplike defect and their interaction are discussed.
Cobalt Chemical Vapor Deposition Process on Molybdenite Basal Plane Observed by Ultrahigh-Vacuum Scanning Tunneling Microscopy
Authors: Komiyama Masaharu , Kiyohara Kohei , Yoda Eisuke , Kubota Takeshi , Okamoto Yasuaki
Published: September 2005

The processes of high-temperature (473 K) resulfidation and cobalt carbonyl adsorption by chemical vapor deposition (CVD) on a cleaved basal plane of a natural molybdenite (MoS2) single crystal were examined by ultrahigh-vacuum scanning tunneling microscopy (UHV-STM) on the nanometer scale. The resulfided cleaved molybdenite basal plane showed a displacement of upper terraces, and a sinusoidal structure at step edges, both of which may be caused by the electronic effect at the surface. Cobalt carbonyl appeared to be adsorbed at both the S- and Mo-terminated edges, resulting in an agglomeration at the step edges on lower terraces with a width of a few tens of nanometers. When this surface with adsorbed carbonyl was sulfided at 513 K for 1 h, most of the adsorbed carbonyl clusters appeared to be desorbed while a small part were dispersed on the terraces in small clusters of 10–20 nm in size. The obtained results are discussed in terms of the preparation of Co-Mo hydrodesulfurization (HDS) catalysts.
Theoretical Analysis of Apparent Barrier Height on an Al Surface: Difference by Measurement Methods
Authors: Totsuka Hideomi , Furuya Shinnosuke , Watanabe Satoshi
Published: September 2005

We have analyzed the difference in apparent barrier height (ABH) by the approach and modulation methods, using the boundary-matching scattering-state density functional method, in which electric states under an applied bias voltage are self-consistently calculated. We found that the approach and modulation methods provide nearly the same calculated ABH values for a wide range of tunneling conductances from 10-11 to 10-5 Ω-1. The change in ABH in the tunneling conductance range from 10-11 to 10-7 Ω-1 is smaller than that in the tunneling conductance range from 10-7 to 10-5 Ω-1, suggesting that some of the observed discrepancies between the two methods may be due to the difference in tip-sample distance. Furthermore, we also found that the change in modulation amplitude, which is caused by the force acting on the tip atom due to the applied bias voltage, can account for the observation that the modulation method provides a smaller ABH value than the approach method.
Focus and Dose Measurement Method in Volume Production
Authors: Ina Hideki , Oishi Satoru , Sentoku Koichi
Published: September 2005

We propose a new inspection method of in-line focus and dose control for semiconductor volume production. We refer to this method as the focus and dose line navigator (FDLN). Using FDLN, the deviations from the optimum focus and exposure dose can be obtained by measuring the topography of the resist pattern on a process wafer that was made under a single-exposure condition. Generally speaking, FDLN belongs to the technology of solving the inverse problem as scatterometry. The FDLN sequence involves following the two steps. Step 1: creating a focus exposure matrix (FEM) using a test wafer for building the model as supervised data. The model means the relational equation between the topography of resist patterns (critical dimension (CD), height, sidewall angle) and FEM's exposure conditions. Step 2: measuring the topography of resist patterns on a production wafers and feeding the topography data into the library to extrapolate focus and dose. To estimate the accuracy of FDLN, we performed some experiments. We developed a FEM with an ArF lithography tool and measured the topography of the FEM with an optical CD measurement tool. Using the topography data, we obtained the following results. Focus: 27.0 nm (5.2 nm) and Dose: 1.8% (1.4 nm). The numerical value in a parenthesis shows the value of the estimated accuracy with changing CD. We also show other experimental results and some simulation results in this paper.
Evaluation of Performance of Proximity Effect Correction in Electron Projection Lithography
Authors: Osawa Morimi , Ogino Kozo , Hoshino Hiromi , Machida Yasuhide , Koba Fumihiro , Yamashita Hiroshi , Arimoto Hiroshi
Published: September 2005

We experimentally evaluated the overall performance of our proximity effect correction method in electron projection lithography. A Si stencil mask for corrected data was fabricated and then exposed using an electron-beam stepper. Shape modification resulted in high linewidth controllability and uniformity of critical dimension (CD) even when the pattern density changed. The deviation in linewidth was 6.6 nm in linearity, and 4.7 nm in the pattern density dependence of a 100 nm line. As well as shape modification, we reduced the pattern density of large patterns by replacing the interior area with mesh patterns in order to produce isolated space patterns. The meshes were well fabricated on the mask. Isolated spaces were successfully formed without resolving the mesh patterns on a resist.
Optimizing Operational Parameters for Z-Pinch EUV Source by Artificial Neural Network
Authors: Zhang Chaohai , Katsuki Sunao , Sakugawa Takashi , Kimura Akira , Fukumoto Haruhiko , Namihira Takao , Akiyama Hidenori
Published: September 2005

Non-equilibrium ionization plays a critical role in Z-pinch gas discharge produced plasma (GDPP) EUV source. However, the physics of the processes, plasma and surface discharges produced, magneto-hydrodynamic, photon radiation transport, and plasma-electrode interactions, which lead to EUV emission, is intrinsically complex. Many simplifying assumption are inevitable with numerical simulations, resulting in low-credibility outcomes. With the learning and generalization abilities, artificial neural networks (ANN) have been applied to model and optimize a Z-pinch plasma source, which is characterized with a experimental design at varied operational parameters including electric power input, applied voltage/current, pulse repetition, MPC parameters, electrode geometry, xenon flow rate as well as convention efficiency, EUV source size, radiation power etc.
Novel Evaluation System for Extreme Ultraviolet Lithography Resist in NewSUBARU
Authors: Watanabe Takeo , Kinoshita Hiroo , Sakaya Noriyuki , Shoki Tsutomu , Lee Seung Yoon
Published: September 2005

A standard assessment system for resist development with extreme ultraviolet (EUV) light was developed. The system for the evaluation of an EUV resist was installed at the BL3 beamline in the NewSUBARU synchrotron radiation facility. This optical system simulates a six-mirror imaging system. Incident light is reflected seven times in the chamber. The centroid wavelength is 13.57 nm. The beam size at the sample surface is 4×4 mm2 and we can take twelve shots for each sample by moving the sample in the lateral direction. Furthermore, a highly sensitive quadrupole mass spectrometer that can measure the mass numbers of ion species from 1 to 500 and is connected to a resist evaluation chamber is used for resist outgassing analysis under EUV irradiation. The main purpose of this whole system is to evaluate the basic physical and chemical properties of various EUV resists candidates, such as sensitivity and outgas characteristics.
10-nm-Scale Pattern Delineation Using Calixarene Electron Beam Resist for Complementary Metal Oxide Semiconductor Gate Etching
Authors: Narihiro Mitsuru , Arai Kohichi , Ishida Masahiko , Ochiai Yukinori , Natsuka Yasutaka
Published: September 2005

We have examined a negative high-resolution electron beam resist, a chloromethylated calix[4]arene resist for advanced gate lithography. We identified safe and ecological developers that can be used in mass production processing lines. Isopropyl alcohol (IPA) or ethanol as a developer provided a high sensitivity. A 9-nm-wide isolated line was obtained when we exposed a 20-nm-thick resist using a 100-kV electron beam and developed it with IPA. We found that IPA development caused slight swelling, thus enabling us to obtain a 15-nm-wide line pattern with a high aspect ratio of approximately 6 when using a 90-nm-thick resist. IPA was the most promising of our tested developers in terms of safety, sensitivity, resolution, and aspect ratio. We also examined the dry etching resistance of the chloromethylated calix[4]arene resist and found that its selectivity to poly-Si was approximately 2, demonstrating that it was sufficiently durable for poly-Si gate etching.
Highly Accurate Grating Reference Fabricated by EB Cell Projection Lithography
Authors: Nakayama Yoshinori
Published: September 2005

100-nm pitch size silicon grating pattern for calibration reference of electron-beam (EB) metrology systems was achieved. Grating patterns with pitch sizes of 240, 200, 160, and 100-nm in thexandydirections were delineated by EB cell projection writing system using grating stencil mask and these resist patterns were transferred in silicon substrate by dry etching. The pitch size error in thexandydirections was within 1 nm and the uniformity in 1.8×1.8-mm chip was under 3 nm within 3σ. More accurate or convenient calibration of the critical-dimension scanning electron microscope are expected compared with conventional calibration using 240-nm pitch reference grating fabricated by laser-interferometer lithography and anisotropic chemical etching.
Nanoimprint of Glass Materials with Glassy Carbon Molds Fabricated by Focused-Ion-Beam Etching
Authors: Takahashi Masaharu , Sugimoto Kohichi , Maeda Ryutaro
Published: September 2005

Micro/nano-imprinting or hot embossing is a target of interest for the industrial production of microdevices. In fluidic micro electromechanical systems (MEMS) applications, polymer materials have been employed for their low cost in the fabrication of economical products. However, glasses are much more suitable for higher-temperature applications or use in reactive chemical environments. In optical MEMS as well, glasses are good candidate materials for enhanced optical properties. In this study, micro/nano-imprinting was employed for Pyrex glass and quartz glass molding, and test structures were successfully fabricated with good fidelity for a 10×10×7 µm microstructure and a 0.3 µm line-and-space pattern with a depth of 0.4 µm.
Line Width Reproducibility of Photo-Nanoimprints
Authors: Hiroshima Hiroshi , Kurashima Yuichi , Komuro Masanori
Published: September 2005

Well-shaped patterns were fabricated by photo-nanoimprinting using a spin-on-glass (SOG) mold, the patterns of which were replicated from a Si master mold by the SOG replica method. The line width reproducibility of the photo-nanoimprint was then evaluated using an atomic force microscope (AFM). Pattern widths with a sub-nm resolution were determined by an edge detection program. The obtained widths included errors attributable to the nonlinearity of the AFM piezo scanner; however, a calibration method using pattern pitches was employed to filter out these errors and allow precise evaluation of line widths. Using this method, the standard deviation of differences between averaged values from 5 measurements of two patterns, which were fabricated on different dies by photo-nanoimprinting, was found to be 0.23 nm. High photo-nanoimprint reproducibility was thus confirmed quantitatively.
Morphology of Iron Silicide Nanorods Formed by Electron-Beam-Induced Deposition Using Ultrahigh-Vacuum Transmission Electron Microscope
Authors: Tanaka Miyoko , Han Ming , Takeguchi Masaki , Chu Fengmin , Shimojo Masayuki , Mitsuishi Kazutaka , Furuya Kazuo
Published: September 2005

We have fabricated Fe silicide nanorods on Si(111) substrates by both deposition at high temperatures and electron-beam-induced deposition (EBID), and observed them with an ultrahigh-vacuum transmission electron microscope. The formation of either nanotriangles or nanorods was observed depending on the surface geometry of the substrates. The nanorods grew along one of the Si<110> directions. In the case of EBID, the size and position of the deposits were controlled by adjusting irradiation time and the position of the electron beams. The longest rods almost reached about 100 nm in length with a 10 nm width.
Growth Manner and Mechanical Characteristics of Amorphous Carbon Nanopillars Grown by Electron-Beam-Induced Chemical Vapor Deposition
Authors: Okada Satoshi , Mukawa Takahito , Kobayashi Ryota , Fujita Jun-ichi , Ishida Masahiko , Ichihashi Toshinari , Ochiai Yukinori , Kaito Takashi , Matsui Shinji
Published: September 2005

We investigated the growth manner and mechanical characteristics of amorphous carbon (a-C) nanopillars formed by electron-beam-induced chemical vapor deposition (EB-CVD). The pillars' inclinations were well explained if we assumed the vertical growth rate to be almost constant within a specified distance from the substrate. The pillars' Young's modulus evaluated by deflection measurement was approximately 29 GPa, which was almost equivalent to that of bismuth, but much smaller than that observed in focused ion-beam-induced chemical vapor deposition (FIB-CVD) pillars.
Modeling the Process of Electron-Beam-Induced Deposition by Dynamic Monte Carlo Simulation
Authors: Liu Zhi-Quan , Mitsuishi Kazutaka , Furuya Kazuo
Published: September 2005

Dynamic Monte Carlo simulation was carried out to investigate the growth model of deposit on film substrates in electron-beam-induced deposition (EBID). Both 200 and 20 keV electrons were used in the simulation to compare the effects of primary beam energy. It was concluded that the deposition can take place on both top and bottom surfaces of thin films. At the beginning stage, the deposit grows preferentially downward from the bottom surface, and the length of the downside part first increases markedly and then becomes gradually saturated. However, the growth of the upside part is steady at an almost constant rate, and its length exceeds that of the downside part due to the saturation of the downside length. The diameter of the deposit also saturates as the number of impinging electrons increases. Although the growth rate of a deposit is lower for 200 keV electrons, they are capable of obtaining a spatial resolution higher than that of 20 keV electrons. The growth model was verified by experimental EBID of tungsten tips on carbon film using 200 keV electrons.
Growth of Pillarlike GaN Nanostructures
Authors: Takeda Satoshi , Ishino Kenei , Inoue Yoku , Ishida Akihiro , Fujiyasu Hiroshi , Kominami Hiroko , Mimura Hidenori , Nakanishi Yoichiro , Sakakibara Shingo
Published: September 2005

We have characterized the growth of GaN nanostructures on Si (111). Hexagonal faceted pillarlike GaN nanostructures (GaN nanopillars) were grown by hot wall epitaxy. The GaN nanopillars were self-assembled. Scanning electron microscopy and atomic force microscopy were used to characterize the samples. The typical diameter of the GaN nanopillars was 200 nm. It was found that GaN nanopillars are grown only on a low-temperature GaN island buffer layer. By changing the annealing temperature of the buffer layer, the density of the GaN nanopillars was controlled from 0.4×108 to 3.5×108 cm-2.
Atomistic Investigations of α-Fe Thin Film Growth on Al (100)
Authors: Chung Chan-Yeup , Chung Yong-Chae
Published: September 2005

The interfacial feature and growth morphology of a Fe-Al metallic bilayer system were quantitatively investigated by molecular dynamics simulation. Fe atoms of 0.1 eV incident energy were deposited on an Al (001) substrate at 300 K. At the interface region, an intermetallic compound was formed and found to be of the B2 structure. However, the Fe/Al system showed different characteristics, such as a layer coverage function and a mixing length, in comparison with other ferromagnetic/nonferromagnetic metallic bilayer systems. The different intermixing behaviors were successfully explained in terms of cohesive energy and lattice matching.
Transport of Charge Carriers in HgTe/CdTe Core-Shell Nanoparticle Film
Authors: Kim Hyunsuk , Park Byoungjun , Cho Kyoungah , Kim Jin-Hyoung , Lee Jun Woo , Kim Dong-Won , Kim Sangsig
Published: September 2005

HgTe and HgTe/CdTe core-shell structured nanoparticles were synthesized by the colloidal method. The photoluminescence (PL) spectrum of a HgTe/CdTe nanoparticle film exhibited an exciton peak at 700 nm, which was blue-shifted by about 400 nm for the HgTe nanoparticle film. The current–voltage curves and photoresponse of the HgTe/CdTe nanoparticle film were compared with those of the HgTe nanoparticle film. When the film is exposed to light, the current of the HgTe/CdTe nanoparticle film decreases in the ambient air while increasing in vacuum. Finally, the temperature dependence of the photocurrent is discussed in this paper.
Electrical Detection of Protein Using Gold Nanoparticles and Nanogap Electrodes
Authors: Tsai Chien-Ying , Chang Tien-Li , Uppala Ramesh , Chen Chun-Chi , Ko Fu-Hsiang , Chen Ping-Hei
Published: September 2005

A method of electrically detecting of protein described is developed using self-assembled multilayer gold nanoparticles (AuNPs) on a SiO2/Si substrate between gold electrodes. Electrical measurements are performed at room temperature using a probe station. A monoclonal antibody is immobilized on the top surface of the first layer of AuNPs (14 nm). The second layer of AuNPs is formed through specific binding among a target antigen [hepatitis C virus, (HCV)], the monoclonal antibody, and the conjugate of a AuNP-polyclonal antibody. Once the specific binding among the monoclonal antibody, target antigen, and polyclonal antibody occurs, a significant electric current is detected through multilayer self-assembled gold nanoparticles between nanogap electrodes. No significant current (<1 pA) can be measured through a monolayer of AuNPs. A significant difference between the IV curves of the monolayer and the multilayer of AuNPs is used to identify whether the target antigen exists in the tested sample.
Fabrication of Nanomanipulator with SiO2/DLC Heterostructure by Focused-Ion-Beam Chemical Vapor Deposition
Authors: Kometani Reo , Hoshino Takayuki , Kondo Kazushige , Kanda Kazuhiro , Haruyama Yuichi , Kaito Takashi , Fujita Jun-ichi , Ishida Masahiko , Ochiai Yukinori , Matsui Shinji
Published: September 2005

High-performance nanotools are very important for nanoscale operation and analysis in the various research studies. To improve the performance of these tools, it is necessary to make three-dimensional (3-D) nano structure devices. We fabricated a 3-D electrostatic nanomanipulator with SiO2/DLC heterostructure by focused-ion-beam chemical vapor deposition (FIB-CVD). In this article, we report on the fabrication and movement check of the 3-D electrostatic nanomanipulator.
Anti-Sticking Effect of Organic Dielectric Formed by Electrodeposition in Microelectromechanical-System Structures
Authors: Sakata Tomomi , Ishii Hiromu , Okabe Yuichi , Nagase Masao , Kamei Toshikazu , Kudou Kazuhisa , Yano Masaki , Machida Katsuyuki
Published: September 2005

In microelectromechanical-system (MEMS) structures, selective encapsulation with an organic dielectric using electrodeposition can prevent sticking. Selective electrodeposition characteristics were investigated on a gold surface using sulfonium cations with epoxy groups as a source material. We observed an incubation period in the initial stage of the deposition. X-ray photoelectron spectroscopy revealed that the cause of the incubation period is the removal of oxygen adsorbed on the gold surface. Applying this technique to the encapsulation of MEMS structures confirmed the anti-sticking effect between an actuator and a gold electrode selectively coated with an organic dielectric.
Fabrication of HfC-Coated Si Field Emitter Arrays with Built-in Poly-Si Thin-Film Transistor
Authors: Nagao Masayoshi , Sacho Yutaka , Matsukawa Takashi , Kanemaru Seigo , Itoh Junji
Published: September 2005

HfC-coated amorphous-Si field emitter arrays (FEAs) controlled by a built-in poly-Si thin-film transistor (TFT) was proposed and fabricated. Such FEAs were fabricated at relatively low temperatures by an Ar ion sputter sharpening so that a low-temperature poly-Si TFT process can be applied. We compared the comb-shaped gate structure and lightly doped drain (LDD)-structured TFT from the viewpoint of controlling field emission current. The LDD-structured TFT with a channel length of 50 µm and an LDD offset length of 2 µm withstands a high source drain voltage of more than 40 V. Successful control of FEAs by built-in TFT was demonstrated in a vacuum chamber. The fabrication and emission control characteristics of such a device will be reported in detail.
Fabrication of Micro Field Emitter Tip Using Ion-Beam Irradiation-Induced Self-Standing of Thin Films
Authors: Yoshida Tomoya , Baba Akiyoshi , Asano Tanemasa
Published: September 2005

We propose a novel standing technique of fabricating a high-aspect-ratio tip structure. The technique utilizes the bending of films induced by ion irradiation. Using this technique, the position and aspect ratio can be easily controlled by the conventional thin-film deposition and photolithography processes. We found that the standing is realized when ion energy is chosen at which the film internal stress at the medium depth of the film relaxes, while low- and high-energy irradiations simply bend up and bend down the film, respectively. We demonstrate the application of the thin-film standing technique to field emitter fabrication.
Fabrication of Low-Frequency AC-DC Thermal Converter with Thermal Mass
Authors: Jung Su-Lack , Eun Duk-Soo , Kim Do-Wook , Kong Seong-Ho , Lee Jung-Hee , Shin Jang-Kyoo , Lee Jong-Hyun
Published: September 2005

The use of a thin film or a planar multijunction thermal converter (PMJTC) for the ac-dc transfer of voltage and current is well established. In general, a three dimensional multijunction thermal converter (MJTC) has the advantage of accuracy and a single junction thermal converter (SJTC) has that of low cost. PMJTCs provide a long-term stability, a high sensitivity and a high-dynamic-frequency range. It is well known that PMJTCs show small ac-dc voltage transfer differences in the audiofrequency range. However, it is difficult to obtain a small ac-dc transfer difference at low frequencies, particularly with thin-film-based thermal converters. The small ac-dc transfer difference at low frequencies is caused by nonlinearities in the heat transport mechanism (in thin films) and in the thermal-to-electric conversion process (in the thermocouples of thin films). This study has been conducteded to achieve a smaller ac-dc transfer difference on thin-film chromel-alumel thermal converters operating at low frequencies. An optional silicon obelisk is formed underneath the thin membrane to minimize ac-dc transfer differences at lower frequencies. The floating obelisk structure enhances the isothermal operation and slows thermal transfer compared with the standard configuration without the obelisk, resulting in a smaller ac-dc transfer difference at low frequencies. Also, it is possible that thin-film thermal converters can be used as the flow sensor and infrared sensor.
Fabrication of Micro Probe Beam Using MEMS Technology for New Vertical Silicon Probe Card
Authors: Kim Young-Min , Yoon Ho-Cheol , Seo Chang-Taeg , Lee Jong-Hyun
Published: September 2005

A silicon micro probe beam using a curled cantilever was designed and fabricated using microelectromechanical systems (MEMS) technology, such as porous silicon micromachining, reactive ion etching (RIE) and Au electroplating. The stress analysis of a micromachined micro probe beam was performed using finite-element ANSYS software. As a result, the basic structure was a multilayer composed of Au/Ni–Cr/Si3N4/n-epi layers. The width and length of the micro probe beam were 40 µm and 600 µm, respectively. Annealing is performed for 20 min at 500°C. The result shows that a deflection over 130 µm can be achieved for a silicon epitaxial layer 5 µm thick. The contact resistance of the micro probe beam was less than 2 Ω.