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Tatsuo KANKI, Daisaku KANEMOTO, Noriaki SANO
2001 Volume 44 Issue 3 Pages
127-130
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The mechanical screw-grooved vacuum pump is known to have a higher evacuation performance for a gas of heavier molecules than that of lighter molecules. In this research, it is newly found that when this type of pump is used to evacuate a mixed gas the inhalation pressure of the gas can be reduced by leaking a gas of heavier molecules within a given volume flow rate. For H
2-N
2 and He-Ar mixtures, relations of the inhalation pressure with flow rate of a heavier gas at several given evacuation flow rates of a lighter gas are clarified experimentally by changing the back pressure and the rotation speed of rotor of the pump. It is also shown that the specific evacuation characteristics can be explained theoretically by a smoothed pressure flow model applying the combined equation of flow and diffusion of a rarefied gas mixture.
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Michikazu KINSHO, Daiji NISHIZAWA, Masahiko UOTA, Tomio KUBO, Yoshihir ...
2001 Volume 44 Issue 3 Pages
131-134
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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In order to study the irradiation effect on alumina ceramic, electron beam irradiation experiment has been performed in electron beam irradiation facility at JAERI. It is possible to irradiate the electron beam at the maximum peak beam current of 30 mA and the maximum beam energy of 3 MeV in this facility. In the experiment the electron beam at the energy of 2.5 MeV was irradiated on the sample of alumina ceramic. The flexural strength of these samples was measured in accordance with the regulation of the JIS. The dose of the electron beam which corresponds to 300 MGy at the beam energy of 2.5 MeV has been irradiated to the 14 kinds of alumina ceramic. The result showed three patterns of the flexural strength for the absorption dose.
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Takafumi SATO, Makoto KAWAMURA, Kuniaki ORIKASA, Nobuaki MINAMI, Koyu ...
2001 Volume 44 Issue 3 Pages
135-138
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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A new ultra high vacuum apparatus combined with reflection high energy electron diffraction (RHEED) and X-ray spectrometer has been developed. The double crystal spectroscopy technique was applied to the X-ray spectrometer. Thin Fe films epitaxially grown on Si (111) surface were observed
in situ by RHEED during Fe deposition and followed annealing. Corresponding to the process the emitted X-ray were measured by the X-ray spectrometer. The FeKα
1 peak was clearly separated from the FeKα
2 peak. The full width at half maximum (FWHM) for the two peaks were 5.77 eV and 7.91 eV, respectively. Although the absolute X-ray intensity is very weak, we obtained high resolution on the sample. Therefore, this method can be widely apply to surface studies.
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Masahiro GOTO, Akira KASAHARA, Masahiro TOSA, Takashi KIMURA, Kazuhiro ...
2001 Volume 44 Issue 3 Pages
139-142
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Thin films of hexagonal boron nitride mixed with copper (h-BN/Cu) were prepared under different depositing conditions. Their surface morphology, internal stress and surface free energy were measured. Many nanometer-sized island structures grew on the surface of the films and their size increased as the deposition time. The values of internal stress and the surface free energy drastically changed with substrate temperature during deposition. The possibility was shown of controlling the thin film properties extensively and of applying it to fabricate friction-controlled materials and reaction-controlled catalysis.
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Shigeki MIZUSHIMA, Masaaki UEKI, Yoshiaki NEZU, Akira OOIWA
2001 Volume 44 Issue 3 Pages
143-146
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Variations in water adsorption on stainless steel surface were measured at the National Research Laboratory of Metrology (Japan) by weighing 1-kg weights in vacuum and in humid air. For this measurement, a vacuum balance with a maximum capacity of 1.2 kg and a resolution of 0.1 μg was used. The dependence of water adsorption on washing and relative humidity of air was investigated respectively using a weight composed of 9 disks with a total geometric surface area of 668 cm
2. The amount of water adsorption per unit area was 0.18 μg/cm
2 before washing, and 0.15 μg/cm
2 after washing at a relative humidity of 50%. The coefficient of relative humidity dependence was measured to be about 0.0075 μg/ (cm
2· %). The effect of coating with TiN was also investigated. The decrease in water adsorption due to TiN coating was about 0.014 μg/cm
2.
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Satoshi MIHO, Yuji YAMAUCHI, Yuko HIROHATA, Tomoaki HINO, Masana NISHI ...
2001 Volume 44 Issue 3 Pages
147-150
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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To produce silicon oxide layer with bubbles, O
2 and He DC glow discharges were conducted for a p-type (100) silicon wafer. After the plasma irradiation, the depth profile of oxygen concentration and surface morphology of the samples were examined by Auger electron spectroscopy (AES) and scanning electron microscopy (SEM), respectively. In the case of O
2 plasma irradiation, the thickness of oxide layer increased with increases of negative bias voltage and substrate temperature. In the case of He plasma irradiation, the bubbles with various diameters were formed on the Si surface. The average size of bubbles increased as the increase of He ion fluence. The size ranged from 0.12 to 0.35 μm. On the other hand, surface density of bubbles decreased when the ion fluence increased. After the He plasma irradiation at RT, the O
2 plasma irradiation was conducted at the temperatures of RT and 873 K. The thickness of oxide layer increased compared to the case of only the He plasma irradiation, when the temperature was RT. In the case of 873 K, the bubble was destroyed and an increase of the oxidation thickness was not large as estimated.
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Michiko YOSHITAKE, Yarrama-Reddy APARNA, Kazuhiro YOSHIHARA
2001 Volume 44 Issue 3 Pages
151-154
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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A technique to modify interface after the formation of interface is desired either from a process requirement or because of the change of material use with time. A novel technique to form an intermetallic compound at the interface between coated layer and substrate by depositing a chosen metal film on the top of a coated layer is presented. The diffusion and interfacial reaction of specimens with top-film/middle-film/substrate structure were investigated. With proper choice of top-film element, top-film element diffused inside without detectable reaction with middle-film and concentrated at the interface between middle-film and substrate followed by intermetallic compound formation. We discuss conditions for obtaining above phenomena and general guide for a choice of top-film element is presented. Key factors are (1) segregation tendency of top-film element on middle-film metal, (2) activation energy of diffusion of top-film element in middle-film and in substrate, and (3) existence of intermetallic compound between top-film metal and substrate in phase diagram. The examples of intermetallic compound formation by the diffusion of top-film element are given in Ti-film/Nb-film/Cu-substrate, Fe-film/Nb-film/Ti-substrate, Cu-film/Fe-film/Zr-substrate, and Fe-film/Zr-film/Ti-substrate.
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Yukio INOKUTI, Kazuhiro SUZUKI
2001 Volume 44 Issue 3 Pages
155-158
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Magnetic properties and textures of TiN, TiCN and TiC-coated silicon steel sheets were investigated. Pole figures of dual textures of these ceramic films and silicon steel samples were measured simultaneously using solid state detector (SSD) auto pole figure apparatus.
Both magnetic flux density B
8 (T) and iron loss W
17/50 (W/Kg) improved in sequences of TiN, TiCN, TiC-coated silicon steel sheets.
{111} pole figure of these ceramic films deposited on (011) [100] single crystal of silicon steel showed the dominant texture of (111) [110] orientation, and (100)
Si-steel pole figure showed the dominant texture of (011) [100] orientation. {111} pole intensities of these ceramic films strengthen in sequences of TiN, TiCN, TiC films.
It is considered that the orientation relationship between ceramic films and (011) [100] single crystal of silicon steel satisfies
(111)
ceramic films // (011)
Si-steel, [110]
ceramic films // [100]
Si-steel.
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Yukio INOKUTI
2001 Volume 44 Issue 3 Pages
159-162
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The elongated morphology of TiN films deposited on SUS430 stainless steel coil has been studied. TiN-coated stainless steel coil has been deposited using a new horizontal-type high current (1500 A) hollow cathode discharge (HCD) gun installed in a continuous ion plating apparatus of air-to-air type.
In the scanning electron microscope (SEM) observation of TiN films after bulge press-forming and 180° bend-forming, the TiN films showed comparatively sharp, straight cracks characteristic of ceramics. However, very small areas across cracks of the TiN films showed the “bridgelike” elongation on TiN-TiN surface matrix. The formation of these bridges was associated with the formation of the continuous convex lines on the film surface.
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Shin KAMADA, Tadashi SAWADA, Wataru SUGIYAMA, Manabu FUJIOKA, Masaru T ...
2001 Volume 44 Issue 3 Pages
163-166
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Our previous analysis of the performance of a scroll vacuum pump assumed the isothermal compression process of the pump. It gave approximately the same ultimate pressures for air and argon as the measured ultimate pressures, but the predicted ultimate pressure for helium was an order of magnitude higher than the measured ultimate pressure. We adopted the adiabatic compression process in this paper to investigate how the compression process would change the ultimate pressure. The effects of the molecular weight and diameter on the ultimate pressure were also investigated. The results of the analysis stated that the ultimate pressure for helium was in the same order of magnitude as the measured ultimate pressure. The ultimate pressure changes with the molecular weight and diameter for light molecules.
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Akira KUROKAWA, Shingo ICHIMURA, Hidehiko NONAKA, Hisao HOJYO
2001 Volume 44 Issue 3 Pages
167-170
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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To measure concentration of binary mixture gas we developed a new method that uses a Quartz gauge together with a capacitance manometer. Because a Quartz gauge's sensor is sensitive to both gas viscosity and gas pressure while a capacitance manometer is just sensitive to gas pressure, the viscosity of the gas can be estimated from pressure indication from both the gauges. If the gas is binary mixture gas and the viscosity of the gas changes monotonically with the concentration, the pressure deviation will give the concentration of binary mixture gas. This method has several merits. One is that we can apply to explosive gases because the sensors do not have any source to ignite such as a heated wire, an energetic light, and an electron source. The other is that because of no source to decompose the gas, this method does not change the concentration of the sample gas after the measurement. Then it is not necessary to discard the sampled gas, and consequently the effective amount of the sample is negligible.
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Isao NAKAMURA, Ichiro TAKANO, Yoshio SAWADA
2001 Volume 44 Issue 3 Pages
171-174
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The mechanical properties of CrCN films on SUS304 substrate have been studied. CrCN films were prepared by the reactive ion beam mixing method. In this method, N
2+ ion irradiation and Cr evaporation were simultaneously carried out in a CH
4 gas atmosphere. N
2+ ions were accelerated at an energy of 10 keV, and the ion beam current densities were changed from 10 to 60 μA/cm
2.
Atomic concentration, chemical state and microstructure of the films were investigated by X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and wear resistance were determined using Knoop hardness tester and pin-on-disk tribometer.
The microstructure of CrCN films prepared at ion current density of 10 μA/cm
2 was observed Cr
2N and CrN peaks. On the other hand, XRD patterns of the films prepared above 30μA/cm
2 suggested that CrN and Cr
7C
3 existed in the mixture phase in these films. The Knoop hardness and the wear resistance of CrCN films prepared above 30 μA/cm
2 showed a high value and a low friction coefficient, respectively. It was considered that the formation of Cr-carbide in CrCN films contributed to the improvement of the mechanical properties.
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Kunio SAKURADA, Kojiro ONO, Yoshifumi AOI, Eiji KAMIJO
2001 Volume 44 Issue 3 Pages
175-178
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Amorphous carbon nitride (CN
x) thin films were deposited on Si (100) substrates by pulsed laser deposition (PLD) under various deposition conditions. The deposited films were characterized by scanning electron microscope (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. The maximum N/C atomic ratio 0.24 was obtained in case of using radical beam source at 400 W of RF input power and 1.3 Pa of N
2 gas pressure in the deposition chamber. N 1s XPS spectra show the existence of N-
sp2C and N-
sp3C bonds in the films. Raman spectra of the deposited films indicated that N-
spC (N≡C) bond in the deposited films were small compared with N-
sp2C and N-
sp3C. The fraction of N-
sp3C increased with increasing N/C atomic ratio of deposited film.
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Akio SUZUKI, Yoshitaka YONEYAMA, Takanori AOKI, Tatsuhiko MATSUSHITA, ...
2001 Volume 44 Issue 3 Pages
179-182
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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It is urgent to establish a new pulsed laser deposition technique to prepare the high-quality transparent conducting film with large area, which is essential to put into practice. We have attempted to fabricate the GZO (ZnO : Ga
2O
3) films by applying a magnetic field perpendicular to the plume generated between the target and the substrate. When the films were fabricated by applying Nd : YAG laser (λ =532 nm) and the magnetic field at the same time, it was found that the carrier concentration drastically increased and the resistivity remarkably decreased and also the surface morphology was improved. By applying an ArF excimer laser (λ=193 nm) and the magnetic field at the same time, the films with rsistivities of the order of 10
-4Ω-cm were obtained at the substrate temperature between room temperature and 350°C. It was proved to be a very useful method for the fabricating of the high-quality transparent conducting films to apply the magnetic field perpendicular to the plume.
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Toshiyuki HIGASHINO, Yuichi KAWAMURA, Atsushi KONDO, Masato FUJIMOTO, ...
2001 Volume 44 Issue 3 Pages
183-186
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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GaAs
0.5Sb
0.5 lattice matched to InP substrates is a promising material for new photonic devices based on InP. In this paper, the molecular beam epitaxial (MBE) growth and characterization of GaAs
0.5Sb
0.5 on (111)B InP substrates were reported. It was found that the Sb mole fraction of the (111)samples is larger than that of the (100)samples. Furthermore, the photoluminescence peak wavelength of the (111)sample (1.46 μm) is shorter than that of the (100)sample (1.54μm), despite the larger Sb mole fraction in the (111)sample. This energy shift observed in the (111)sample may possibly be induced by the decrease in the spontaneous ordering.
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Kazuto KOIKE, Takashi TANAKA, Shuwei LI, Mitsuaki YANO
2001 Volume 44 Issue 3 Pages
187-190
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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PbTe-base materials such as PbEuTe and PbSnTe are promising for lasers and detectors in the 3-30 μm region, and high-quality PbTe growth is a key issue to integrate these devices on GaAs substrates. Due to a large lattice mismatch, however, PbTe films on GaAs substrates are apt to contain twins and misorientations. This paper describes that single domain PbTe growth is realized by using a buffer layer of CdTe on GaAs substrates. This is because both of these tellurides are lattice matched each other. Although the PbTe/CdTe heterointerface easily becomes rough due to the Te precipitates on CdTe buffer layer, a Cd-termination prior to the PbTe growth is found to be effective to keep the interface smooth. It is also revealed that a Te-rich condition under high-temperature growth is favorable to obtain high-quality PbTe films.
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Masato FUJIMOTO, Yuichi KAWAMURA, Hideaki HARADA, Atsushi KONDO, Toshi ...
2001 Volume 44 Issue 3 Pages
191-194
Published: March 20, 2001
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In
0.53Ga
0.47As/GaAs
0.5Sb
0.5 type II quantum well structures lattice-matched to InP substrates are a very attractive material system for mid-infrared lasers in the 2μm wavelength region. It is expected to get longer wavelength laser operation with increasing Sb composition (y) in the GaAs
1-ySb
y layer. This letter reports the Sb composition dependence and the GaAsSb thickness dependence of the photoluminescence properties of the InGaAs/GaAsSb type II MQW structures.
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Akitaka YOSHIGOE, Yuden TERAOKA
2001 Volume 44 Issue 3 Pages
195-198
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The effects of translational kinetic energy of incident O
2 molecules for intial Si(001) oxidation at room temperature have been investigated by using a supersonic molecular beam technique and photoemission spectroscopy. The oxygen saturation coverage on Si(001) surface increased with increasing the translational kinetic energy of O
2. Two threshold energies, corresponding to the Si dimer backbond oxidation and the second layer (sub-surface) Si atoms backbond oxidation were observed at 1.0 eV and 2.6 eV, respectively. We clarified the relationship between the Si oxidation structure (Si
x+ ; x=1, 2, 3, 4) in Si-2
p photoemission spectra and the translational kinetic energy of O
2 in the initial Si (001) oxidation.
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Nami SAKAMAKI, Toshu AN, Kazuyuki UEDA
2001 Volume 44 Issue 3 Pages
199-201
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Behavior of Ag atoms on a Si(100) surface has been investigated using a coaxial impact collision ion scattering spectroscopy (CAICISS). After Ag deposition at room temperature followed by the annealing in the range of 200-500°C, three-dimensional Ag island was observed. In the case of Ag deposition at 500°C, a 2 × 3 structure and a surface peak of He ions scattered by Ag atoms were observed by LEED and CAICISS, respectively. The Ag-Ag spacing of 2 × 3 structure along the [110] direction was calculated as 7.6 Å. The atomic hydrogen was adsorbed on the 2 × 3 surface, and the 2 × 3 structure collapsed and the three-dimensional island was formed.
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Junya HORIO, Kimio OKUNO
2001 Volume 44 Issue 3 Pages
202-205
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Semiconductor (Si and Ge) -metal alloy formation, semiconductor alloy film-metal interface states and intermixing phenomenon are investigated by atomic-resolution field ion microscopy (FIM). Silicon vapor-deposited onto a tungsten tip surface is very reactive on thermal heating at above 850 K, whereas germanium is less interactive than that of silicidation processes with the substrate tungsten atoms. Intermixing phenomenon of silicon and the W substrate is resulted locally after the silicon is vapor-deposited onto the tungsten tip on heating at around 1000-1100 K. Their atomic traces which indicate the intermixing phenomenon disappered completely after the topmost three atomic layers of the tungsten substrates were field-evaporated. The atomic depth of the silicide reaction is differ locally. For germanium films, extensively intermixing phenomenon such as that observed at silicon and tungsten interface however does not observed. A germanide film is formed by reacting with the topmost atomic layer of the W substrate surfaces and therefore consist of one monolayer.
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Akiko N. ITAKURA, Tetsuya NARUSHIMA, Masahiro KITAJIMA
2001 Volume 44 Issue 3 Pages
206-208
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Recently it was found that a low temperature and high speed oxidation was achieved by plasma of rare gas and oxygen mixture. In our system, using krypton as a mixed rare gas, oxidation rate was a few times higher than oxygen without mixture gas. We have measured a time evolution of surface stress during oxidation using plasma of rare gas and oxygen mixture. It's remarkable that the oxide film made by the mixture plasma had been grown without any stress from the thickness of 5 nm to 8 nm. It still had no compressive stress at 8 nm.
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Yuji YAMAUCHI, Syuhei MORI, Yuko HIROHATA, Tomoaki HINO, Yutai KATOH, ...
2001 Volume 44 Issue 3 Pages
209-212
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Deuterium retention and desorption properties of SiC/SiC composite after deuterium ion irradiation were investigated by means of thermal desorption spectroscopy. Carbon composition measured by Auger electron spectroscopy was considerably large, 90 at.%, which was due to the special heat treatment to the SiC fiber. X-ray diffraction analysis suggested that the material investigated was amorphous silicon carbide with fine crystalline phases. After deuterium ion irradiation, retained deuterium desorbed in forms of HD, D
2 and CD
4. Thermal desorption spectrum of D
2 had a single peak at 1050 K. The D
2 spectrum was similar to that of CFC rather than that of SiC. Amount of retained deuterium was approximately 5 × 10
21 D/m
2, which was comparable to that of CFC or SiC. Amount of desorbed CD
4 was 5 × 10
19 CD
4/m
2, which was approximately 1/4 of the CFC.
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Atsushi FUKUI, Hideaki KASAI, Hiroshi NAKANISHI, Ayao OKIJI
2001 Volume 44 Issue 3 Pages
213-216
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The lifetime of Shockley states on metal surfaces is calculated on the assumption that the Coulomb interaction between electrons in Shockley states is mainly responsible for the finite lifetime of these states, and that the Coulomb interaction would be screened by the bulk electrons. With single-particle wave functions of Shockley states, the Fourier expansion component of the screened Coulomb potential,
Vs, is calculated, and the dependence of
Vs on the lattice constant and the width of the projected band gap at the edge of the first Brillouin zone are investigated. A second-order perturbation calculation with respect to
Vs is made for the self-energy of a single electron in Shockley states, and then the lifetimes of these states on Cu(111) and Ag(111) surfaces are evaluated.
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Hitoshi SASAKI, Hiroshi TSUJI, Hiroko SATO, Yasuhito GOTOH, Junzo ISHI ...
2001 Volume 44 Issue 3 Pages
217-220
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Negative-ion beam modification of polystyrene was observed by atomic force microscope (AFM). Negative ions were implanted into polystyrene for improvement of neural attachment properties. The reason why neural attachment properties of polystyrene surface were improved by negative-ion-implantation was mainly discussed by surface hydrophylicity. In some case, the changes of hydorophylicity by negative-ion-implantation weren't adapted to the changes of neuron attachment properties. As a factor of neural attachment properties, surface morphology was investigated. Ag
- (20 keV) or C
- (10 keV) were implanted into polystyrene at a condition of 1 × 10
151 × 10
16 ions · cm
-2. Negative-ion-implanted polystyrene was observed by AFM, and roughness (Ra) was calculated. Both unimplanted and negative-ion-implanted polystyrene showed Ra of about 1.5 nm. Roughness of polystyrene surface didn't change remarkably by negative-ion-implantation. Surface morphology didn't have a lot of influence on neural attachment properties of negative-ion-implanted polystyrene surface.
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Hidehiko NONAKA, Akira KUROKAWA, Shingo ICHIMURA, Tetsuya NISHIGUCHI, ...
2001 Volume 44 Issue 3 Pages
221-224
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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We built a new type ozone killer based on the redox reactions between cuprous and cupric oxides and applied it to the decomposition of low-pressure highly concentrated ozone. The analysis of the exhaust gas from the ozone killer by low-temperature thermal desorption measurement shows that ozone flux of 1.6 PaLs
-1 can be decomposed completely to oxygen when the copper fins in the ozone killer were heated to 470°C. The copper fins, however, must be kept at even higher temperatures to decompose continuous and larger-flux of ozone since the oxidation of the fins turned out to proceed into the bulk at 470°C.
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Hiroshi TSUJI, Tomohiko SAGIMORI, Ken'ichi KURITA, Yasuhito GOTOH, Jun ...
2001 Volume 44 Issue 3 Pages
225-227
Published: March 20, 2001
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Copper negative ions were implanted in crystalline substrate of titanium dioxide (rutile) at 50 keV with dose of 6.4 × 10
16 ions/cm
2. The as-implanted samples showed small absorption peaks at photon energy of 2.15 eV in addition to strong absorption above 3.1 eV. After 1 hour thermal treatment at 400°C, the absorption peak placed at 1.9 eV. This photon energy of absorption was in good agreement with estimated value of surface plasmon resonance absorption of copper nanoparticles calculated by Mie theory.
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Hideaki HARADA, Katsuto TANAHASHI, Akihiro KOUKITSU, Takeshi MIKAYAMA, ...
2001 Volume 44 Issue 3 Pages
228-231
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Nitrogen doping has attracted much attention because it dramatically reduces void defects in as-grown CZ Si. Various forms of nitrogen have been proposed but primary factor on determining these structures has not been well understood yet. We analyze the atomic stress effect by the valence force field model and calculated the atomic strain energy. It is found that the strain energy determines the stable structure of N
2 and N
2-V, whereas the presence of unpaired electron determines that of interstitial N and substitutional N.
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Satomi TABUCHI, Masaki TANAKA, Tadashi YONEKURA, Masaaki YOSHITAKE
2001 Volume 44 Issue 3 Pages
232-235
Published: March 20, 2001
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We prepared Y
2O
3:Eu
3+ thin films on silver substrates which are mirror polished. They are deposited by 50-300 nm with the RF (radio frequency) -sputtering method. They were annealed at 300-500 °C for 3-10 min. We found the deposited films needed the heat treatment at 500°C for over 10 min in the furnace to emit fluorescence. But the films on silver substrates became granular and mirror surfaces turned to be clouded after this heat treatment. So we tried another heat treatment by the radiation heating with the halogen lamp in the low-pressure chamber. And after irradiating the light of the halogen lamp for 270 sec at 3 cm from the substrates, we got transparent films that emitted fluorescence with almost the same intensity as those heated at 500°C for 10 min in the furnace.
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Akio SUZUKI, Masanari FURIKI, Takanori AOKI, Tatsuhiko MATSUSHITA, Shi ...
2001 Volume 44 Issue 3 Pages
236-239
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Transparent p-i-n junction based on ZnO was fabricated by radio-frequency magnetron sputtering and pulsed laser deposition methods, and its photovoltaic effect was examined. The p-type and i-type layers consist of CZO film (ZnO : CuO, optical energy gap Eg
opt= 3.0 eV) and undoped ZnO film (Eg
opt= 3.3 eV) fabricated using sputtering method, respectively. The n layer is GZO film (ZnO : Ga
2O
3, Eg
opt =3.6 eV) prepared by laser ablation method. For CZO films, an average transmittance of 63% in the visible region, the lowest resistivity of 26 Ω-cm and the maximum Seebeck coefficient of +200 μV/K were obtained. The photovoltaic effect was observed in a see-through structure of CZO/undoped ZnO/GZO/glass substrate by illumination of AM-1 light from both faces of the structure. It was recognized that in the series-connected-structure of CZO/ZnO/GZO + Si solar cell, the photovoltage was effectively caused with two peaks in the wavelength near 350 nm and 700 nm.
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Okio NISHIMURA, Kazuhiko TONOOKA, Katsuyoshi SHIMOKAWA
2001 Volume 44 Issue 3 Pages
240-243
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The magnetoresistive Ag-Fe (amorphous alloy system) thin films were deposited on silicon substrates at room temperature by an rf magnetron sputtering system. The magnetoresistive properties of the samples was investigated in relation to the sputtering conditions, to increase the magnetoresistance of the as-deposited thin films at room temperature. The maximum magnetoresistance of 1.9% (at 200 kA/m) was found in the sample with sputtering rf power at 125 W, gas pressure at 2 Pa, and film thickness of about 200 nm.
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Takanori AOKI, Akio SUZUKI, Tatsuhiko MATSUSHITA, Masahiro OKUDA
2001 Volume 44 Issue 3 Pages
244-247
Published: March 20, 2001
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The In-Zn-Ga oxide films (50nm) were prepared on the glass and the polycarbonate substrates by radio-frequency magnetron sputtering using In, Zn and Ga
2O
3targets. The typical film composition was estimated by EDS as to be In : Zn : Ga = 88.75 : 10.17 : 1.08. The transmittance changes of 4169% at 400 nm and 2555% at 350 nm were obtained between the as-deposited state and the annealed state (500°C×10 min). There were the reflectance changes of about 40% at 350400 nm for the sample with the alminum film as reflection layer. The ability to record on these oxide films (on the glass substrate) without protection layer, using Nd : YAG laser (λ = 355 nm, 3 ns) was confirmed, and a revolution test (λ = 406 nm, NA = 0.65) was performed for a polycarbonate disk structure with the In-Zn-Ga oxide films and a alminum film as the reflection layer : a carrier to noise ratio (CNR) more than 30 dB was recognized.
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Yoshinori MORITA, Heizo TOKUTAKA, Kikuo FUJIMURA, Kazuhiro YOSHIHARA, ...
2001 Volume 44 Issue 3 Pages
248-251
Published: March 20, 2001
Released on J-STAGE: April 23, 2010
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The Self-Organizing Map (SOM) developed by Teuvo Kohonen is a powerful tool for Data Mining, knowledge discovery and visualization of high dimensional data. The SOM is being applied to problems of chemical analysis. The SOM simultaneously performs topology preservation of the data space whiles quantizing the data space formed by the input data. In this paper, we will discuss Auger Electron Spectroscopy (AES) Spectra Analysis System using SOM via Internet (Web Chemical SOM system). We will also discuss the X-ray Photoelectric Spectroscopy (XPS) chemical element map and its verification.
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Tatsuo IWATA, Tomomi YOSHIMOTO
2001 Volume 44 Issue 3 Pages
252-255
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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A new technique for continuously detecting the slope of the Fowler-Nordheim plot has been developed. The system, which consists of analog signal processing circuits and lock-in amplifier, gives not only the slope of the Fowler-Nordheim plot but also the output proportional to the work function of a field emitter surface. The developed system was used to measure the change in work function of a field emitter surface during heating. Thermal desorption spectra from a Re field emitter covered with adsorbed residual gases has been obtained by differentiating the work function versus temperature curve. The thermal desorption peak assigned as a desorption of adsorbed hydrogen was detected at the heating temperature about 500 K. Some relatively small desorption peaks reflecting chemical reactions on emitter surface were also observed at higher heating temperatures.
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Masaaki YASUDA, Keiji TAMURA, Ryuhei KATSUSE, Hiroaki KAWATA, Kenji MU ...
2001 Volume 44 Issue 3 Pages
256-259
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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A Monte Carlo model has been developed to simulate spin-polarized secondary electrons emitted from ferromagnetic materials. The spin direction of the generated secondary electrons are determined according to the conduction band polarization and the spin-dependent inelastic mean free paths for spin-up and spin-down electrons are introduced. The primary energy and incident angle dependence of the secondary polarization are studied with the simulation. We show that these characteristics of the secondary polarization are explained from the point of view of the mean generation depth of the secondary electrons.
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Hiroaki KAWATA, Hidetomo IYANAGA, Takashi MATSUNAGA, Masaaki YASUDA, K ...
2001 Volume 44 Issue 3 Pages
260-263
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Both the current flowing through an antenna coil and the voltage supplied to the coil were measured for Ar inductive coupled plasmas (ICP) at a pressure of 13 Pa. Since a large current flowed through the antenna coil even under no plasma condition, the difference of the antenna coil currents between under no plasma and ICP was measured by using the cancel circuit. Spatial distributions of the plasma density were also measured by Langmuir probes. The RF power dependence of the plasma density agreed to that of the antenna coil current when the cancel circuit was used. The radial distribution of the plasma density,
np (
r), had the peak below the antenna coil center. Positions of the charged particle generation in the plasmas were discussed based on
np (
r). The plasma density decreased as increasing the radial distance from the coil center. For the RF power of 150 W the decreasing rate was larger than that for the RF power of 300 W. The values of the coupling coefficient increased as increasing the RF power. The result could be explained based on the RF power dependence of
np (
r).
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Takashi KUBO, Makoto TANAKA
2001 Volume 44 Issue 3 Pages
264-267
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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In this paper, the dependence of the structure of cathode surroundings on the several plasma parameters was studied using the asymmetrical parallel plate radio frequency plasma reactor. In order to prevent the plasma diffusing to the cathode behind, two technical approaches have been chosen to implement the grounded metals on the surroundings. The one approach is to use the insulator and the metals, and the other is to use the metal plates only. In both cases, the two dimensional distributions of the electron densities were measured by using the self-compensated Langmuir probe.
The results indicate that the intense localization of electron density has been observed even under the pressure of 6.7 Pa.
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Naoaki SAITO, Kazuyoshi KOYAMA, Mitsumori TANIMOTO
2001 Volume 44 Issue 3 Pages
268-271
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Generation of clusters and micro-particles in RF discharge CVD plasmas is a serious problem of how to minimize degradations of characteristics of amorphous-silicon solar cells. In previous studies, only atoms and small size clusters have been studied with mass spectrometers, while fine-particles of a sub-micro level were observed by optical scattering. It is necessary to study all of particles in plasmas.
We have developed a mini time-of-flight mass spectrometer with a two-stage reflector (Min-TOF) to study growth processes of large clusters and fine particles from atoms and small clusters in Si
xH
y plasmas. The Min-TOF is about 1 m in length but both a high mass resolution up to 2, 500 and a wide mass range more than 200, 000 u have been attained.
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Toshiaki YASUI, Hirokazu TAHARA, Takao YOSHIKAWA
2001 Volume 44 Issue 3 Pages
272-275
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Deposition method of ITO thin films with large area was developed. It utilized sheet shaped electron cyclotron resonance (ECR) plasma. It is composed of slot antennas on a rectangular waveguide, permanent magnets around the slots and a target within the discharge chamber. Microwaves of 2.45 GHz are radiated from the slots and generated plasma along the waveguide. With Ar sputtering, ITO thin films were deposited with thickness uniformity of ± 4.4% within 120 mm and deposition rate of 2.75 nm/min. Its resistivity was about 4 × 10
-4 Ωcm, and its transparency was above 70% at 550 nm without glass substrate.
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Yoshio MIURA, Hideaki KASAI, Ayao OKIJI
2001 Volume 44 Issue 3 Pages
276-279
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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We investigate the rotationally inelastic diffraction (RID) of D
2(H
2) scattered from Cu(001) and discuss how isotope effects influence the RID probabilities of D
2(H
2) by performing First Principles Quantum Dynamics Calculations that include all six degrees of freedom of D
2(H
2) on a density functional theory based potential energy surface. We show that the RID probabilities initially increase with increasing incident energies due to the activated nature of D
2(H
2) dissociation on Cu(001), which qualitatively agree with recent experimental RID peaks measured for D
2/Cu(001). Furthermore, comparing the RID probabilities of D
2 and H
2, we observe strong isotope effects. Due to the small threshold energy of D
2 for rotational excitation and diffraction, as compared to H
2, the RID probabilities of D
2 are larger than those of H
2 in the low incident energy region. With further increase in incident energies, however, the RID probabilities of D
2 become smaller than those of H
2. We explain these isotope effects on the RID by showing the wave functions of D
2(H
2) on Cu(001).
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Kunihiro NOBUHARA, Hiroshi NAKANISHI, Hideaki KASAI, Ayao OKIJI
2001 Volume 44 Issue 3 Pages
280-283
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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We investigate the behavior of a H atom on metal surfaces. The potential energy curves (PECs) for the H atom adsorption on and absorption in Cu(111), Pt(111), and Pd(111) are calculated within the density functional theory. We show stronger dependence of the potential energies on the lateral position of the H atom at the position further from the surface in the case of Pt(111) than in the case of Pd(111), and no lateral position dependence in the case of Cu(111). Contrary to this, when the H atom comes close to and adsorbs on the surface, the dependence of its adsorption energy (a depth of potential well outside the surface) on the lateral position in the case of Cu(111) is stronger than in the case of Pd(111), and in the case of Pt(111) such dependencies are hardly seen and their adsorption energies are nearly the same. When the H atom penetrates the first layer of the surface, the activation barrier at a so-called fcc hollow site in the case of Pd(111) is the lowest in three surfaces.
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Kazuyuki UEDA, Keiko OGAI
2001 Volume 44 Issue 3 Pages
284-286
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Electron-stimulated desorption (ESD) measures adsorbed low-Z elements on solid surfaces. A TOF-ESD system reveals not only mass separation in the spectrum of desorbed ions but also kinetic energy distributions which reflect the chemical bonding energy of adsorbed elements. Therefore, a time-resolved measurement of TOF-ESD in scanning mode provides a 2-dimensional imaging of hydrogen and oxygen for different chemical bonding energies. We apply the scanning TOF-ESD to the line-&-space made of Si and SiO
2.
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Mamoru SAKAUE, Hideaki KASAI, Ayao OKIJI
2001 Volume 44 Issue 3 Pages
287-290
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Time-resolved two-photon photoemission (time-resolved 2PPE, TR2PPE) spectroscopy is a powerful tool for studying ultrafast electron dynamics which can correlate with adparticle (atom and molecule) dynamics on metal surfaces. We develop theories of TR2PPE spectroscopy and clarify how the adparticle motions affect the TR2PPE spectra for covalent and ionic adsorption systems. On the basis of the obtained results, we demonstrate that the peak structure in the 2PPE energy spectra in the long pump-probe delay time region can provide information on the mechanism of adsorption, desorption and vibrational excitation of the adparticle on the surface.
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Yuji YAMAUCHI, Toshiharu SAKURAI, Yuko HIROHATA, Tomoaki HINO, Masana ...
2001 Volume 44 Issue 3 Pages
291-293
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Change of photoluminescence properties of porous silicon due to helium ion irradiation before or after anodization was investigated. After the anodization, the photoluminescence spectrum was observed approximately at a wavelength of 640 nm. After only the ion irradiation, no luminescence was observed. For the case with the ion irradiation before anodization, the peak intensity of luminescence decreased compared to the case without the ion irradiation. The peak wavelength shifted to a lower wavelength region. Namely, the blue-shift took place. With an increase of the ion fluence, the peak wavelength shifted further, and the peak intensity became smaller. It is presumed that the blue-sift of the peak is due to changes of the porous structure and nanocrystal state. For the case with the ion irradiation after the anodization, the photoluminescence disappeared, because of destruction of the porous structure by the ion irradiation.
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Kazuyoshi ISHIDA, Koji YATSUSHIRO, Katsuzo OKADA
2001 Volume 44 Issue 3 Pages
294-297
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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A fundamental study on the seizure mechanism, during sliding friction, of carbon steels was carried out at sample temperature from 300 K to 20 K in a vacuum. The influence of experimental conditions, such as contacting load and sample temperature, on the seizure was examined by measuring the delay time of seizure and mean frictional force. From these results, it was found that the delay time of seizure increased and the mean frictional force on seizure decreased, as the sample temperature decreased. According to the X-ray diffraction analysis in a wear area, compressive residual stress at 150 K or less was larger than those at higher temperature. It was also found that the seizure occurrence region exists in sample temperature versus contacting load. And a fundamental mechanism on the seizure of carbon steels at low temperature in a vacuum was discussed from the viewpoints of the flash temperature and the cooling rate.
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Katsumasa SUZUKI, Takayuki SATOU, Yoshio ISHIHARA, Hiroki TOKUNAGA
2001 Volume 44 Issue 3 Pages
298-301
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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The chambers of Metal Organic Chemical Vapor Deposition (MOCVD) equipment are opened at regular intervals, in order to remove the by-products on the inner surface of the reactor chambers. After regular maintenance, it is difficult to remove water molecules adsorbed on the inner surface of chambers, so the through-put of wafers is difficult to improve. The purpose of this work is to present the method to remove adsorbed water molecules on the inner surface of chambers quickly. For this purpose, we use an in-situ and real-time moisture monitor based on near-infrared laser absorption spectroscopy and continuously measure the moisture concentration in MOCVD equipment exhaust gases at the experiment. It was clarified that the baking efficiency is improved by using the high thermal conductivity gases such as hydrogen (H
2) gas and that the purge time is shorten by introducing trimethylaluminum (TMA) to purge gas under room temperature condition.
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Michiko SASAKI, Isao NAKAMURA, Ichiro TAKANO, Yoshio SAWADA
2001 Volume 44 Issue 3 Pages
302-305
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Tribological properties of Ti, TiN and TiO
2 films based on Ti element were investigated in a high vacuum simulating a space environment. Stainless steel (304SS) polished to a mirror surface was used as sample substrates. Ti, TiO
2, and TiN with 0.2 μm in film thickness, were prepared on the substrates by vacuum evaporation, ion beam assisted evaporation, and dynamic ion mixing, respectively. The chemical state and atomic composition of the film were analyzed by X-ray photoelectron spectroscopy (XPS), and the microstructure was measured by X-ray diffraction (XRD). The tribological examination was carried out using a high vacuum equipment (3 × 10
-5 Pa) with a wear tester of Pin-On-Disk type. The wear surface was observed with an optical microscope and a scanning laser microscope.
The friction coefficients of stainless steel, Ti, TiN in the atmosphere showed a lower value than that in the high vacuum, because an oxygen or moisture in the air has a role of lubrication. Therefore, in the case of oxide films such as TiO
2, it is considered that the friction coefficient in the high vacuum showed the same value in the atmosphere.
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Yuki TOGASHI, Yuko HIROHATA, Tomoaki HINO
2001 Volume 44 Issue 3 Pages
306-309
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Carbon nitride (CN
X) films have been prepared by an rf magnetron sputtering apparatus with a graphite target. As a discharge gas, N
2-Ar mixture gas was employed. In order to investigate an effect of ion bombardment on hardness of the films, the gas flow ratio of Ar to N
2, f
Ar/f
N2, was changed from 0 to 2, and negative bias was applied to the substrate in the range from 0 to 100 V. The atomic composition of the films was analyzed by XPS and bonding states by FTIR and Raman spectroscopy. The ratio of N to C in the films, N/C, varied from 0.3 to 0.7. Knoop hardness of the films increased with the increases of f
Ar/f
N2 and negative voltage. The hardness increased with an increase of the ratio of tetrahedral C-N bond to total C-N bonds. The maximum hardness obtained was 94 GPa when the content of tetrahedral C-N bond was approximately 80%.
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Effect of Crystal Structure and Form
Hajime YOSHIDA, Yuko HIROHATA, Tomoaki HINO, Kazuyuki NAKAMURA, Masato ...
2001 Volume 44 Issue 3 Pages
310-313
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Deuterium retention of carbon dust was investigated by two methods, i.e. one is deuterium gas absorption and the other is deuterium ion irradiation. After the gas absorption, retained deuterium desorbed in forms of D
2 and HD. Saturated amount of retained deuterium due to the gas absorption at 100 Pa was approximately 10
-3 in the atomic ratio D/C, when the temperature range was from 973 K to 1173 K. This amount was 10 or 100 larger than that of powdered graphite or bulk graphite, respectively. However, trapping energy of deuterium in the carbon dust was 0.22 eV, almost the same as that of the graphite. After the deuterium ion irradiation to the carbon dust, the retained deuterium desorbed in forms of D
2, HD, CD
4 and C
2D
4. The amount of retained deuterium due to the deuterium ion irradiation was 0.55 in the atomic ratio D/C, almost same as the graphite.
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Tadashi NAKAMURA, Kunio OKIMURA
2001 Volume 44 Issue 3 Pages
314-317
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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Titanium atom densities in Ti-O
2 rf (13.56 MHz) magnetron sputtering were measured by using an atomic absorption method. Dependence of Ti atom densities on O
2 flow rate, applied rf power and Ar pressure were investigated. Spatial profile of Ti atom densities at a total pressure of 3.5 Pa was also shown.
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Tsuyoshi KOYANAGI, Hironori ASADA, Yasuhiro FUKUMA, Naoto NISHIMURA
2001 Volume 44 Issue 3 Pages
318-321
Published: March 20, 2001
Released on J-STAGE: October 20, 2009
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An amorphous IV-VI diluted magnetic semiconductor Ge
0.7Mn
0.3Te film has been prepared by the RF sputtering on a glass substrate at room temperature. Fine crystalline wires could be sucessfully formed in the amorphous matrix by scanning a focused laser beam irradiation. The uniform crystalline pattern has been obtained with a low laser power. It was clarified that the crystalline phase in the amorphous matrix is ferromagnetic. The magnetic transport properties of crystalline wires prepared by phase transformation have been also investigated and compared with those of crystalline wires prepared by the photoetching process. The different magnetoresistance behaviors were observed when the magnetic field was applied along the transverse direction of these wires.
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