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Volume 48, Issue 5
Displaying 1-14 of 14 articles from this issue
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Articles
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Takayuki TOMARU, Yoshio SAITO, Tomio KUBO, Yoshihiro SATO, Masao TOKUN ...2005 Volume 48 Issue 5 Pages 301-303
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSOutgassing rates and optical absorption coefficients of five kinds of black colored coatings, i.e. Ultra-Black NiP (UB-NiP), Phos-black II, Raydent, diamond-like-carbon formed on electrochemical buffed SS surface (ECB+DLC) and Alumite, have been examined to be used as an optical absorber in the high vacuum system of interferometric gravitational wave detectors. The outgassing rate and optical absorption coefficient of UB-NiP were q = 2.2×10-5 t -1.2 [Pa m3/sec/m2] (0.2≤t [hour]≤100) and 99.89% for 1064 nm in wavelength, respectively. These are considered as high performances. ECB+DLC had the optical absorption coefficient of 65% and its outgassing rate was two orders of magnitude lower than that of UB-NiP. It is concluded that UB-NiP is suitable for coating on small optical devices such that high efficiency of optical absorption was required. On the contrary, ECB+DLC coating is useful when it is applied to devices having a large area.View full abstractDownload PDF (500K) -
Jannatul NAYEEM, Sakura Nishino TAKEDA, Fumihiko MATSUI, Ken HATTORI, ...2005 Volume 48 Issue 5 Pages 304-308
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSRoom temperature scanning tunneling microscopy (STM) has been carried out on two newly synthesized organic molecules, octabutylgerma-4-pericycline C40H72Ge4 and dodecaphenylgerma-6-pericycline C84H60Ge6, at atmospheric pressure condition. A regular array of cluster-like patterns and square patterns are observed for C40H72Ge4 molecules. Straight lines structures of regular periodicity of about 5.5 nm are noticed for C84H60Ge6 molecule. Some molecular islands are also observed for both molecules by STM. Therefore the molecules tend to self-assemble on the graphite surface. Spectra obtained from X-ray Photoelectron Spectroscopy (XPS) and X-ray Fluorescence Spectroscopy (XFS) support the molecular assembly on the substrate surface even in an ultra high vacuum condition.View full abstractDownload PDF (1316K)
Letters
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Aki TOSAKA, Tetsuya NISHIGUCHI, Hidehiko NONAKA, Shingo ICHIMURA2005 Volume 48 Issue 5 Pages 309-312
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSUV light-exited ozone has been applied for rapid low-temperature oxidation of silicon in a wafer-transfer type chamber. Oxidation was made in almost 100% ozone atmosphere with KrF excimer laser (248 nm) which enables the effective supply of O (1D) atoms to the processed surface. In this system, SiO2 film with a thickness of more than 3.5 nm is achieved even as low as 200°C. Uniform 2.9 nm film formation over 5-inch wafer with a thickness fluctuation of 0.1 nm was also obtained when KrF laser irradiation area was enlarged by a cylindrical concave lens. Current-voltage measurement has been employed to characterize SiO2 films and it is confirmed that the catastrophic breakdown field strength was 13 MV/cm. Processing pressure dependence of density of O (1D) atoms which contributing to the oxidation was estimated. Experimental result that the thickness of SiO2 film increases by decreasing the processing pressure agrees with our estimated result at the pressure range between 340 Pa and 820 Pa.View full abstractDownload PDF (1030K) -
Tetsuya NISHIGUCHI, Takeshi NOYORI, Yoshiki MORIKAWA, Mitsuru KEKURA, ...2005 Volume 48 Issue 5 Pages 313-316
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSWe have deposited silicon dioxide (SiO2) film at temperatures lower than 300°C by supplying Hexamethyldisilazane (HMDS) and O3 gas with nearly 100% concentration alternately and cyclically. The 100%-O3 gas has confirmed to be reactive enough to decompose the HMDS gas into CO2, H2O as well as the precursors leading to SiO2 deposition such as SiO even at room temperature. The physical characterization of thus deposited film gives a refractive index of 1.45-1.51, no Si-CH3 bond content and a process-dependent Si-OH content in the film. The film deposited by 10 Pa-HMDS and 2700 Pa-100%-O3 alternate supply has had a minimum Si-OH content and a good insulating property, i.e., leakage current density of lower than 10-7 A/cm2 at the electric field application of 4 MV/cm. This property is better than the film deposited by plasma-enhanced chemical-vapor-deposition using SiH4/O2 gas at 350°C.View full abstractDownload PDF (545K) -
Makoto SAKURAI, Fumiharu NAKAJIMA, Takunori FUKUMOTO, Nobuyuki NAKAMUR ...2005 Volume 48 Issue 5 Pages 317-320
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSA novel electron beam ion source was developed for nanoprocesses using highly charged ions. The ion source was designed to optimize the efficiency of ion production and extraction based on the trajectory calculations of electrons and ions traveling through the ion source. A commercial super-conducting magnet (Helmholz coils, 3 T) cooled by a closed-cycle refrigerator is used to reduce the operating costs. The separate vacuum chambers design enables 250°C baking of electrodes in the ion source to realize ultrahigh vacuum condition by removing the magnet chamber without venting.View full abstractDownload PDF (423K) -
Junichiro KAMIYA, Norio OGIWARA, Michikazu KINSHO, Tomohiro TAKAYANAGI2005 Volume 48 Issue 5 Pages 321-324
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSThe extraction kickers in Rapid Cycling Synchrotron (RCS) of Japan Proton Accelerator Research Complex (J-PARC) are installed in the vacuum chamber against electrical discharge. Therefore, outgas from the components have large effects on the vacuum system of the accelerator. We have succeeded in reducing the outgas from the components, which are made of ferrite core and aluminum alloy, by baking them before construction of the magnet. The ferrite cores were baked at 200 deg C in the vacuum about 300 hours, while the components made of aluminum alloy at 150 deg C about 70 hours. Main outgas from both materials was known to be water by mass spectroscopy, and the pressure after baking has been decreased by two or three order of magnitude. We also report the reduction method for outgas while the magnet is stored in.View full abstractDownload PDF (488K) -
Seppen-Katamuki Analysis of Field Emission from Carbon Nanotubes after KrF-excimer Laser IrradiationYoshinori KAWAMURA, Katsuyuki ISHIZU, Yasuhito GOTOH, Hiroshi TSUJI, J ...2005 Volume 48 Issue 5 Pages 325-328
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSWe measured the field electron emission properties of carbon nanotubes (CNTs) with and without laser irradiation. As a result, the threshold voltage was found to decrease by laser irradiation. However, the improvement for current stability was not observed so much. Analyzing the emission characteristics with using Seppen-Katamuki (S-K) plot, it was found that the structural change of CNTs caused the decrease of the turn-on voltage. And we roughly estimated the shape of the CNTs emitter with S-K plot.View full abstractDownload PDF (294K) -
Toshihiko KOJIMA, Kouji NAKAMURA, Yasuhito GOTOH, Hiroshi TSUJI, Junzo ...2005 Volume 48 Issue 5 Pages 329-332
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSWe propose the application of silicon field emitter array (Si-FEA) to resolve the problem of wafer charging in the ion implantation process. This article reports experiments conducted to review the basic property of Si-FEA. This time, we measured the energy distribution of electrons emitted from three types of Si-FEA with different number of tips and gate apertures. The result is different from that of platinum field emitter array (Pt-FEA) in some points. First, half bandwidth of Si-FEA distribution is a little smaller than that of Pt-FEA. Second, the energy peak of Si-FEA shifts to lower energy side from Fermi level. Such phenomenon doesn't happen in the energy distribution of Pt-FEA.View full abstractDownload PDF (552K) -
Hiroshi AMEKURA, Kenichiro KONO, Naoki UMEDA, Naoki KISHIMOTO2005 Volume 48 Issue 5 Pages 333-336
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSZinc-ion implantation combined with thermal oxidation was carried out to fabricate zinc-oxide (ZnO) nanoparticles (NPs) in silica glass (SiO2). A SiO2 substrate was implanted with Zn+ ions of 60 keV to 1.0×1017 ions/cm2. In as-implanted state, the sample shows a strong absorption peak at ∼4.8 eV and a weak one at ∼1.2 eV due to Zn metallic NPs. After annealing in oxygen gas at 700°C for 1 hour, the absorption in the visible region disappears and a new distinct absorption edge appears at ∼3.3 eV. The grazing-incident-angle x-ray diffraction (GXRD) confirms the formation of ZnO NPs. The ZnO NPs show a photoluminescence (PL) peak at 3.32 eV under pulsed nitrogen-laser excitation. Annealing at 900°C induces an additional shift of the absorption edge to ∼5.3 eV. The additional shift is due to the formation of a Zn2SiO4-phase which has been confirmed by GXRD.View full abstractDownload PDF (439K) -
Hiroomi GOTO, Koichi SUDOH, Hiroshi IWASAKI2005 Volume 48 Issue 5 Pages 337-338
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSRelaxation of step edge structures on SrTiO3(001) surface was studied using scanning tunneling microscopy. Real time observation of the step morphology was performed during annealing at 690°C. We analyzed step edge straightening quantitatively by examining the decay of Fourier components of step structures. From the wavelength dependence of the time constant, we have concluded that the dominant mass transport in straightening of step edge structure is adatom exchange between step edges and terraces.View full abstractDownload PDF (427K) -
Youhei KONDOU, Takeru NAKASHIMA, Takeshi TANAKA, Toshinori TAKAGI, Sat ...2005 Volume 48 Issue 5 Pages 339-342
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSPlasma based ion implantation (PBII) with negative voltage pulses to the test specimen has been applied to the sterilization process as a technique suitable for three-dimensional work pieces. Pulsed high negative voltage (5 μs pulse width, 300 pulses/s, -800 V to -15 kV) was applied to the electrode in this process at a gas pressure of 2.4 Pa of N2. We found that the PBII process, in which N2 gas self-ignitted plasma generated by only pulsed voltages is used, reduces the number of active Bacillus pumilus cell. The number of bacteria survivors was reduced by 10-5 x with 5 min exposure. Since the ion energy is the most important processing parameter, a simple method to estimate the nitrogen ion energy from distribution of nitrogen atoms in Si implanted by PBII was developed. The implanted ion energy is discussed from the SIMS in depth profiles.View full abstractDownload PDF (579K) -
Syunsuke HACHIUE, Yuden TERAOKA2005 Volume 48 Issue 5 Pages 343-345
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSAtomic N+ ions with 3 keV translational kinetic energy, which were mass separated by using a Wien filter, were irradiated at SiO2/Si(001) surfaces. By applying high energy resolution photoemission spectroscopy with synchrotron radiation, it was found that the SiO2 overlayer (1.6 nm∼2.8 nm) and the interface were effectively nitrided even at room temperature as well as the Si(001) substrate. N-1s photoemission spectra for the nitrided SiO2/Si(001) were deconvoluted into four component peaks. They were assigned to (a) N(-Si)3, (b) N(-SiO)3, (c) (H-)2N-Si, and (d) O-N(-Si)2, respectively.View full abstractDownload PDF (624K) -
Takashi MIURA, Mai HASHIMOTO, Naoko IZUMI, Ichiro ARAKAWA2005 Volume 48 Issue 5 Pages 346-349
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSWe measured spectra of light-emissions during sliding friction between diamond and quartz in ambient gases of He, Ne, and Ar at 10-103 Pa. Two types of the light emission were observed; one has a band spectrum specific to each gas and the other has a continuous spectrum from 300 to 600 nm. The shape of the latter spectrum was almost the same for all the ambient gases while the pressure dependence of the intensity differed from gas to gas. The continuous spectrum is highly similar to that of photoluminescence caused by the oxygen vacancy in quartz. Microscopic spectroscopy revealed that the source of the continuous spectrum was on the friction track in the electric discharge region. Experimental results suggest that electrons or ions in the gas discharge stimulate the oxygen vacancy in quartz.View full abstractDownload PDF (770K) -
Yoshikazu SUZUKI, Tsuneo FUKUDA, Hiroshi NAKAYAMA2005 Volume 48 Issue 5 Pages 350-352
Published: 2005
Released on J-STAGE: August 11, 2006
JOURNAL FREE ACCESSWe performed in situ scanning tunneling microscopy observation of oxygen reaction on the Si(111)7×7 surface at high temperatures. In spite of passive oxidation regime, we found that voids having the depth just one bilayer were formed at the initial stage of reaction. We found that the number density of the void was well represented by power laws. We applied the two-dimensional nucleation theory to this void formation and found that the critical nuclei were i = 1.46(647 K) and i = 14.7(751 K). We found the transition from active to passive oxidation with constant substrate temperature and oxygen exposure rate. The transition was quantitatively reproduced by the numerical simulations.View full abstractDownload PDF (805K)
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