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Hiro MOCHIDZUKI, Yuji YAMAUCHI, Yuko HIROHATA, Tomoaki HINO
1999 Volume 42 Issue 3 Pages
135-138
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Thermal desorption properties of hydrogen and deuterium retained in polycrystalline molybdenum were studied by using a technique of thermal desorption spectroscopy, after hydrogen or deuterium ion irradiation with an ECR ion source. The energy of H
+ or D
+ was 1.7 keV. Thermal desorption spectra of H
2 or D
2 had a peak at around 200°C and a shoulder at temperature higher than 200°C. The peak temperature shifted to higher direction as the fluence increased. The amount of retained hydrogen or deuterium increased with the fluence. The retention did not saturate in the fluence range up to 10
19 ions/cm
2. The amount of retained hydrogen or deuterium decreased with increase in irradiation temperature. At 100°C, the deuterium retention was approximately a half of that at RT. After irradiation at 200°C, only little desorption was observed.
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Sakae S.INAYOSHI, Sonoko TSUKAHARA, Kazuya SAITO, Akira KINBARA
1999 Volume 42 Issue 3 Pages
139-142
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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By Si film coating on stainless steel by radio frequency (RF) magnetron sputtering we have developed very low outgassing state where the outgassing rate of Si coated sample is one tenth of the uncoated electrolytically polished stainless steel sample. As a preliminary step to find other coating techniques for an inner wall of vacuum chamber, electron beam deposition was examined by small samples in this paper. Outgassing properties of small samples were measured by thermal desorption spectroscopy (TDS). The outgassing depends on the film structure that was determined by deposition angle. When a Si film was deposited at low incident angle, the film was dense and the outgassing rate was as low as a Si film deposited by sputtering, whereas the outgassing rate of a Si film deposited at large incident angle was larger than that of uncoated stainless steel.
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Kazuyuki SAKAMOTO, Daiyu KONDO, Yoshimitsu USHIMI, Akio KIMURA, Akito ...
1999 Volume 42 Issue 3 Pages
143-146
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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We have investigated the coverage-dependent electronic structures of C
60 molecules adsorbed on the Si (111) -(7×7) and Si (001) -(2×1) surfaces using photoelectron spectroscopy. The valence band spectra show that the highest occupied molecular orbital (HOMO) of a C
60 molecule splits into two peaks on both surfaces at a coverage lower than 0.25 monolayer. These split peaks are assigned to be the shifted HOMO and the bonding state, with the polarization-dependent measurements and the Si 2
p core level spectra. The binding energies of the molecular orbitals and the C 1
s core level show a small shift on the Si (001) -(2×1) surface, and no shift on the Si (111) -(7×7) surface with decreasing the coverage. These results indicate that the strong interaction between C
60 molecules and the surfaces has a covalent character on the Si (111) -(7×7) surface, and both covalent and ionic characters on the Si (001) -(2×1) surface. We attribute the difference in the charge states of C
60 molecules to the different surface structures.
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Takaaki KAWAMURA, Akira ISHII
1999 Volume 42 Issue 3 Pages
147-150
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The growth on GaAs (100) is studied by Monte Carlo simulation in comparison with the growth on Si (100). The step density variations during the growth and their temperature dependence show good agreement with the reported experimental RHEED intensity oscillations. This result and the corresponding surface morphology show that As plays a dominant role during the growth.
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Kouhei OKADA, Akiyoshi NAGATA, Hideo OKAYAMA, Hiromu ISA
1999 Volume 42 Issue 3 Pages
151-154
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Properties of yttria stabilized zirconia (YSZ) electrolyte thin films for solid oxide fuel cells (SOFCs), which were grown by RF magnetron sputtering method under the prepared conditions of the reduced pressure of 0.8 Pa and the substrate temperature of RT, have been investigated on the dependencies of the anneal temperatures and the sputtering RF powers. The sputtered films annealed at 1600°C were found to be the closed YSZ electrolytes having the bulk oxide structure without the pin-holes. A SOFC having the annealed YSZ electrolyte thin films indicated a stable power generation property with 0.9 V that this value nearly equals to the theoretical OCV.
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Tomoaki TATSU, Akiyoshi NAGATA, Hideo OKAYAMA, Hiromu ISA
1999 Volume 42 Issue 3 Pages
155-158
Published: March 20, 1999
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Properties of magnesia stabilized zirconia (MSZ) electrolyte thin films for solid oxide fuel cells (SOFCs), which were grown by the plasma-enhanced chemical vapor deposition (PECVD) method, have been investigated on the microwave power dependencies and the anneal effect. MSZ thin films grown by microwave power of 500 W were found to be the columnar and closed electrolytes having a higher conductivity of 10
-3 S/cm. A SOFC having the annealed MSZ electrolyte thin films indicated a stable power generation property with 0.5 V although its value was reduced to lower half than the theoretical OCV of 0.915 V.
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Naoki YASUMARU, Hiroyuki MAGARA, Toshio IBE
1999 Volume 42 Issue 3 Pages
159-162
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Austenitic type 304 stainless steel was ion-nitrided and subsequently ion-plated with CrN or CrNi-N whose Ni content was varied from 11 at% to 50 at%. The ceramic film of CrN coated onto the pre-nitrided steel showed the good wear resistance even under a heavy load. Further, the CrN film with a thickness of 10 μm showed the minimum wear loss among the CrN films of 319 μm. As for the cermet films of CrNi-N composed of Cr
*N and Ni, the CrNi-N film with Ni content of 11 at% coated onto the pre-nitrided steel showed the best wear resistance compared with the CrN film or CrNi-N films with high Ni content. Its good wear resistance was maintained even at the thick film over 20 μm, being different from the tendency of CrN film.
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Hideki YAMAMOTO, Noriaki SAIGA, Katsumi NISHIMORI
1999 Volume 42 Issue 3 Pages
163-166
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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ZnO thin films were deposited on several LiNbO
3 substrates with specified orientation by a rf-sputtering technique. The films were deposited on the substrates at room temperature or 573 K in various oxygen-argon atmospheres. From X-ray diffraction pattern, ZnO (002) reflection peak was measured for both of x and z cut LiNbO
3 substrates. ZnO (002) peak intensity depended on gas flow rate of oxygen to argon and anneal temperature. When the film was deposited on z cut LiNbO
3 substrate at 573 K in O
2 (20%) + Ar (80%) gas and annealed at 773 K in air, the film showed the crystalline growth highly oriented at [002] direction.
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Masanori ICHIYAMA, Yosihiro SAWAHIRA, Yasunobu KURODA, [in Japanese], ...
1999 Volume 42 Issue 3 Pages
167-170
Published: March 20, 1999
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Effects of compositionally gradient structure and discharge gas pressure on microhardness and adhesion of ZrN/Zr/ ZrO
2/substrate and ZrN/ZrO
2/substrate films have been studied. The apparatus used to deposit the films was an UHV-type sputtering machine with a Zr magnetron cathode. The compositional graduation of the films was formed by changing reactive gas flow rate gradually for a constant discharge current in the reactive sputtering. For film prepared, microhardness and adhesion strength were examined. The highest hardness was achieved for a ZrN/ZrO
2 film with a gradient interlayer deposited at an Ar partial pressure of 0.4 Pa. The ZrN/ZrO
2 or ZrN/Zr/ZrO
2 films with interrupted interfaces showed lower microhardnesses compared to the films with gradient interfaces. Although the adhesion strength increased as Ar partial pressure increased, the microhardness decreased. Thus, it was concluded from the experimental results obtained that the ZrN/ZrO
2 films with gradient interfaces deposited at a low Ar pressure yielded a high performance as a hard coating.
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Yasuhiro YAMAUCHI, Tadahisa NAGAMI, Satoru KISHIDA, Heizo TOKUTAKA
1999 Volume 42 Issue 3 Pages
171-174
Published: March 20, 1999
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We prepared Bi
2Sr
2CaCu
2O
y (BSCCO) single crystals by a self flux method and heated them in air, Ar gas and O
2 gas. Then, we investigated their surface compositions and chemical bond natures of constituent elements by the X-ray photoelectron spectroscopy (XPS). From the results, we found that the carbon and the impurity oxygen on the BSCCO single crystal surfaces were efficiently removed by the heat-treatments in air and O
2 gas, and that the chemical bond natures of Cu, Sr and O did not change.
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Nobuhito TSUCHIYA, Yuji YAMAUCHI, Yuko HIROHATA, Tomoaki HINO
1999 Volume 42 Issue 3 Pages
175-178
Published: March 20, 1999
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Measurements on optical emission intensities of nitrogen ion and nitrogen molecular, and on plasma parameters such as electron density were carried out to study on the influence of a hydrogen dilution to the nitrogen plasma. The emission intensities increased with admixing of hydrogen up to the hydrogen partial pressure ratio, P
H2/P
N2=0.5. Above the this ratio, the emission intensities decreased.
The plasma density increased and the nitrogen gas pressure decreased with an increase of hydrogen partial pressure ratio. Then, the maxima of the emission intensities appeared at the hydrogen partial pressure ratio, P
H2/P
N2=0.5.
A silicon sample was exposed to the plasma. Analysis for the surface atomic composition showed that the nitrogen amount in the surface was largest at the ratio, P
H2/P
N2=0.5.
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Mitsuo TSUTSUI, Toshiki KOBAYASHI, Naoto KIKUCHI, Eiji KUSANO, Hidehit ...
1999 Volume 42 Issue 3 Pages
179-182
Published: March 20, 1999
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Electron carrier transport phenomena in indium tin oxide (ITO) films were studied. The films were deposited by dc magnetron sputtering using a sintered oxide target for the substrate temperature of room temperature to 773 K. Crystallinity of the films was estimated by X-ray diffraction (XRD) method. Temperature dependence of carrier concentration and mobility were estimated by Hall voltage measurements for a temperature range 10 K to room temperature. The XRD results show that the crystallinity of the ITO films increases with the substrate temperature. The crystalline size obtained from the XRD results also shows the improvement in crystallinity. The Hall measurement results revealed that all the ITO films were degenerated semiconductors. In addition, the negative temperature dependence of the Hall mobility was observed for films deposited at 673 or 773 K. This negative temperature dependence implies that the dominant scattering center for electron carriers in highly crystallized ITO films is phonon scattering.
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Norihiro OKUMURA, Hideo FURUHASHI, Toshio YOSHIKAWA, Akinori MAEDA, Sh ...
1999 Volume 42 Issue 3 Pages
183-186
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Vanadyl-phthalocyanine (VOPc) films were prepared on KBr substrate by MBE. They were characterized with RHEED, optical absorption spectra in visible and infrared regions (UV/VIS) and SEM. The thickness of prepared films is above 100 nm. The second and third harmonic generations (SHG and THG) of films were also measured by a Maker fringe method using a Nd·YAG laser. From these results, it was concluded that films are epitaxy films. We also estimated that the SH intensity of VOPc films are about 20 times higher than that of a Y cut quartz crystal and the third-order susceptibility χ
(3) of VOPc film is about 3 times greater than the value reported recently by Fang et al.
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Tastuo ASAMAKI, Tatsuya YAMAGUCHI, Hitoshi UDAGAWA, Michiro TAKEUCHI, ...
1999 Volume 42 Issue 3 Pages
187-190
Published: March 20, 1999
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Poisson's equation, ∇
2φ=-ρ/ε
0, shows that if the electric potential distribution or electric field in the space in which ions are generated is held constant, the distribution of the electric charge density is constant. By dividing the ion collectors of the gauge into two sections, and controlling the distribution ratio of ion current at a constant level against pressure, a constant distribution of the electric charge density is secured. Based upon this idea, a prototype of the magnetron gauge is built.
It is found that the ion collector current is directly proportional to the pressure in a range of 1×10
-52×10
-9 [Pa].
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Asami HOTOTA, Akihiro INABA, Kenji EMOTO, Tatsuo ASAMAKI
1999 Volume 42 Issue 3 Pages
191-194
Published: March 20, 1999
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A new magnetron vacuum gauge, having two ion collectors for controlling the electric field in the cylindrical anode, has been developed. The effect of the electrode structure on the ion currents were studied by varying the electrode spaces.
It is found that the distribution ratio of the two ion currents is controllable when the spacing between the anode and shield electrodes, and further, between the two ion collector electrodes and the shield electrode are optimized. In this configuration the measured ion current is directly proportional to the pressure in a range of 3 × 10
-61 × 10
-4 Pa.
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Makoto TANAKA, Ryu TANIGAWA, Hidenobu NAKAMURA, Toru KANAJI, Kojiro SU ...
1999 Volume 42 Issue 3 Pages
195-199
Published: March 20, 1999
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The cascade static lens gauge (CSL gauge) has very high sensitivity and has been developed for the measurements of the total pressure in extremely high vacuum range. In this study, the effects of small shift of the filament position on the sensitivity were investigated, and it was clarified that the small shift affects on the sensitivity only a little. However, at the same time, it was found in the experiment that the potential of the filament (bias potential) with good sensitivity is not same with it predicted by computer simulation. Depending on these new knowledge and several new idea, a new electrode system of a CSL gauge which will have a very high sensitivity is proposed.
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Takashi CHIJIMATSU, Hiroki KURISU, Setsuo YAMAMOTO, Mitsuru MATSUURA, ...
1999 Volume 42 Issue 3 Pages
200-203
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Surface roughness and vacuum characteristic of pure titanium plates modified by buffing and electrolytic polishing were investigated by atomic force microscopy (AFM) and thermal desorption spectroscopy. Surface roughness of the titanium plates decreases after polishing and a typical value of the surface roughness (Ra) is 12.9 nm at 10 × 10 μm range by AFM. The magnitudes of ion currents due to outgassing such as H
2, H
2O, N
2 and CO
2 from the polished titanium plates are smaller than those from the polished stainless steel plates by a factor of 10. The polished titanium is used to prepare a vacuum chamber with O-ring seals. The chamber is pumped down by a turbo molecular pump and the pressure reaches 1.2 × 10
-7 Pa after a 78 h baking at 150°C.
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Kenya AKAISHI, Kazuhiro EZAKI, Yusuke KUBOTA, Osamu MOTOJIMA
1999 Volume 42 Issue 3 Pages
204-207
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The outgassing rates of an unbaked vacuum chamber were measured by the orifice pumping and the pressre rise methods. It was found that the measured outgassing rates were dependent on pumping speed. The change of residual gas composition in the test chamber during measurement of outgassing rate was observed by a quadrupole mass analyzer. Before cut-off pumping, water vapor was a predominant desorbing gas, but after cut off pumping, hydrogen became a predominant desorbing gas instead of water.
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Kenji NODA, Jeong-Tak RYU, Mitsuhiro KATAYAMA, Kenjiro OURA
1999 Volume 42 Issue 3 Pages
208-211
Published: March 20, 1999
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Using time of flight impact collision ion scattering spectroscopy (TOF-ICISS), we have investigated Sn thin film growth on clean Si (111) and Si (111) √3 × √3-Sn surfaces. Sn forms crystalline film with β-Sn structure on both surfaces. However, the difference of interface structure plays a decisive role for the growth orientation of the grown Sn thin film. The growth orientational relationship of the Sn film grown on the clean Si (111) surface is found to be Sn (100) <011>//Si (111) <011> and Sn (100) <010>//Si (111) <112>, but the Sn film grown on Sn (111) √3 × √3-Sn surface is rotated by 30° relative to that on the clean Si (111) surface, Sn (100) <010>//Si (111) <011> and Sn (100) <011>// Si (111) <112>. The reason for the rotation is explained by the reduction of the lattice mismatch between the β-Sn and √3 × √3-Sn lattice.
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Osamu KUBO, Jeong-Tak RYU, Hitoshi TANI, Toru HARADA, Takashi FUSE, To ...
1999 Volume 42 Issue 3 Pages
212-216
Published: March 20, 1999
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We have investigated the structural change process induced by atomic hydrogen interaction with the 4 × 3 surface phase in the In/Si (100) system using scanning tunneling microscopy (STM) and coaxial impact collision ion scattering spectroscopy (CAICISS).
It has been revealed that when the 4 × 3-In surface is exposed to atomic hydrogen, small and uniform In clusters, the size of which grows with increasing substrate temperature during hydrogen exposure, are formed on the Si surface. These clusters are not epitaxially grown crystallites but amorphous or poly-crystalline in contrast with those of H/ Si (111) √3×√3-Ag, -Al or-Pb surfaces. The initial stage of structural change process is also different from H/ Si (111) √3×√3-Ag or H/Si (111) 4 × 1-In surfaces but similar to H/Si (111) √3×√3-In surface.
The In-denuded regions show not 1 × 1 but 4 × 1 periodicity. From this result, we have confirmed that the underlying atomic layer of a silicon substrate in the Si (100) 4 × 3-In surface phase is reconstructed with a 4 × 1 periodicity and proposed a model of 4 × 3-In structure.
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Hyeongmin JEON, Akimitsu HATTA, Toshimichi ITO
1999 Volume 42 Issue 3 Pages
217-220
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Carbon films deposited unintentionally on substrate holder and reactor walls significantly influenced on diamond nucleation and growth using magneto-active microwave plasma chemical vapor deposition method (MPCVD). In this study, the etching process of such carbon films for a reproducible cleaning process has been investigated. In order to clarify the effect of magneto-active microwave pure-oxygen plasma, CO
2 and CO products were mainly measured as functions of treatment time, plasma pressure, microwave power and substrate bias voltage. The results obtained show that there are three time regions in the etching process which may depend on the spatial distributions of the oxygen-related radicals and the carbon films in the chamber. It is found that relatively inefficient etching proceeded in the third stage, the origin of which is discussed.
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Hiroshi TSUJI, Syuichi NAKAMURA, Takaaki YOSHIHARA, Yasuhito GOTOH, Ju ...
1999 Volume 42 Issue 3 Pages
221-224
Published: March 20, 1999
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Atomic bonding state of carbon-negative-ion beam deposited films was investigated. Mass-separated ions of C
- and C
-2were deposited on Si (100) and Si (111) at a low ion energy of 50-400 eV under 1 × 10
-6 Pa. Deposited films showed a broad Raman band in 1400-1600 cm
-1 similar to diamond-like carbon films. From details of C
1s spectra in X-ray photoelectron spectroscopy (XPS), it was found that the fraction of C-C (sp
3) bonds increased with an increase in ion energy up to 75 eV/atom of ions for both ion species, and then gradually decreased with the further increase in ion energy. The kinetic energy of ions is considered to contribute to the formation of metastable sp
3 bonds, but the excessive kinetic energy might destroy the sp
3 bonds. As a result of the ion energy dependence of carbon interatomic bonding state, the sp
3 bond fraction of more than 80% was obtained at ion energy of 75 eV/atom for both C
- and C
-2 depositions.
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Hiroki TAKASHIMA, Yoshifumi AOI, Eiji KAMIJO
1999 Volume 42 Issue 3 Pages
225-228
Published: March 20, 1999
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B-C-N thin films were prepared onto silicon substrates by pulsed-laser deposition (PLD) method. The targets were prepared by hot-pressing of mixtures of hexagonal boron nitride (h-BN) and graphite powders with various weight ratios. The deposited films were evaluated by the x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and x-ray diffraction (XRD). XRD patterns of the deposited films show that intensity of peak corresponding to h-BN (002) tends to increase with increasing content of h-BN in the target. Raman spectra show that carbon in the deposited films composes carbon network like diamond-like carbon (DLC) or amorphous carbon. FT-IR spectra and XPS spectra indicate existence of B-C and C-N bond as well as that of B-N and C-C bond within the deposited films.
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Takaaki YOSHIHARA, Hiroshi TSUJI, Yasuhito GOTOH, Junzo ISHIKAWA
1999 Volume 42 Issue 3 Pages
229-232
Published: March 20, 1999
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CN negative-ion beam deposited films have been investigated with respect to dependencies of a nitrogen atom content and interatomic bonding state upon the incident ion energy. The CN negative ions extracted from a sputter-type negative ion source were deposited on a silicon substrate n-Si (100) at various ion energies in a range of 25-500 eV. From Rutherford backscattering spectroscopy (RBS) measurement, the maximum of N/C ratio and atomic density in films were obtained N/C = 0.60, 1.56 × 10
23 atoms · cm
-3 at an ion energy of 75 eV, respectively. From X-ray photoelectron spectroscopy (XPS) analysis, nitrogen atoms in the film were found to be mostly combined with carbon atoms in bonding states of C = N and C ≡ N. The maximum fraction of C-N bond reached 11% of nitrogen content at an ion energy of 500 eV. In Raman spectroscopy, CN
xfilms showed similar Raman bands to those of the diamond like carbon (DLC) film.
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Nobuo SAITO, Isamu NAKAAKI, Hiromu IWATA, Tomuo YAMAGUCHI, Sigeaki NAK ...
1999 Volume 42 Issue 3 Pages
233-236
Published: March 20, 1999
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Oxygen doped amorphous GeC : H films have been deposited by a reactive rf magnetron sputtering of Ge target in neon-methane and oxygen gas mixtures. The effect of oxygen partial pressure ratio
R on the structural, optical and electrical properties of the films was investigated. With increasing
R, the bonding configuration concerning oxygen-bonds appears and the optical bandgap increases. Both the dark conductivity and photoconductivity show maxima at
R= 10%. They decrease above
R=30%, which is ascribed to the increase in the Ge-C and Ge-O bonds.
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Hiroshi TSUJI, Shinichi IKEMURA, Hiroko SATO, Yasuhito GOTOH, Junzo IS ...
1999 Volume 42 Issue 3 Pages
237-240
Published: March 20, 1999
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Modification of the tissue-culture polystyrene (TCPS) surface by the silver-negative-ion implantation was investigated with respect to contact angle, selective cell attachment properties and control of cell orientation. Negative-silver ions were implanted into TCPS at a condition in energy and dose region : 5-30 keV and 1 × 10
14-1 × 10
16 ions/cm
2. By this implantation, the surface of TCPS was changed to be hydrophobic, and loosed its cell attachment property. In the patterned implantation through a mask with slits of 40 μm-wide and 4 mm-long with a spacing of 40 μm, the cells attached on the unimplanted region of TCPS. In addition, most of the attached cells aligned along a stripe pattern.
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Kazunori SUZUKI, Hideo MAEHARA, Noriyuki YOSIMOTO
1999 Volume 42 Issue 3 Pages
241-244
Published: March 20, 1999
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6-dibutylamino-1, 3, 5-triazine-2, 4-dithiol (DB) was vapor-deposited onto Fe substrates. The monomeric DB and polymeric one (PDB) were employed as the deposit source. The molecular orientation, film thickness and bonding state of the formed thin films were characterized using FT-IR, ellipsometry and XPS. Ratio of perpendicular orientation and concentration of dimerized molecules in the films significantly increased at evaporated temperature with changing the source material from DB to PDB. From this fact, it is suggested that the control of molecular orientation in the DB thin films can be achieved by varying the molecular weight of the source materials and substrate temperature.
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Katsushi HASHIMOTO, Tomonobu NAKAYAMA, Noriyuki YOSHIMOTO, Masahito YO ...
1999 Volume 42 Issue 3 Pages
245-248
Published: March 20, 1999
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We have observed, using the scanning tunneling microscope (STM), that molecules at the β- (ET)
2I
3 (001) surface are removed by scanning the STM tip. Such removal of the molecules is followed by a systematic change in the directions and the structures of the surface steps. We discuss the stability of the observed steps, based on the molecular arrangement on (001) surfaces terminated by I
3 and ET layers. Both the change of the surface steps and the STM images successively recorded at the same area indicate that the I
3 and ET layers are alternately removed by the STM tip.
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Chikanori INO, Takashi NAITO, Yasuhiro IGASAKI
1999 Volume 42 Issue 3 Pages
249-252
Published: March 20, 1999
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The effects of doped IIIa elements on the electrical, optical and structural properties of ZnO films prepared by rf magnetron sputtering using sintered ZnO targets doped with IIIa oxide, have been studied.
We found that the carrier concentration increased as dopant concentration in the target increased regardless of kinds of IIIa elements and that Hall mobility of carrier decreased depending on doped elements in the order of Al, Ga and In, when dopant concentration of these elements were approximately equal.
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Takahiro KATAYAMA, Yuichi KAWAMURA, Akiko YAMAMOTO, Hideki TAKASAKI, H ...
1999 Volume 42 Issue 3 Pages
253-256
Published: March 20, 1999
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Impurity doping characteristics of the GaAsSb layers lattice-matched to InP substrates grown by molecular beam epitaxy was studied. It was found that Si is an effective n-type dopant and Be is an effective p-type dopant for GaAsSb layer lattice-matched to InP. The carrier concentration is comparable to that of the InGaAs layer lattice-matched to InP. Optical properties were also studied for doped GaAsSb layers. It was found that the photoluminescence (PL) intensity for the doped GaAsSb layers is much larger than that of the undoped GaAsSb layer.
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Xin-Shan LI, Tsunehisa TANAKA, Yoshihiko SUZUKI
1999 Volume 42 Issue 3 Pages
257-260
Published: March 20, 1999
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The deposition rate and crystallograghic structure of PZT thin film deposited by facing target sputtering have been studied experimentally in this paper. The deposition rate increases with increase of sputtering power or with decrease of substrate temperature, and it has a minimum value when the thin film is deposited at the total gas pressure from 0.05 to 1.2 Pa. The perovskite phase and pyrochlore phase exist in all as-deposited samples of PZT thin films, and the relative content of various phases is varied with sputtering conditions.
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Yoshiharu KAKEHI, Akio OKAMOTO, Yoshiaki SAKURAI, Yoshito NISHIKAWA, S ...
1999 Volume 42 Issue 3 Pages
261-264
Published: March 20, 1999
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A LiNbO
3 thin film was successfully fabricated onto a sapphire (001) substrate using pulsed laser deposition. The film quality was largely affected by substrate temperature, oxygen gas pressure, laser fluence and laser repetition frequency. By adjusting these conditions, a highly c-axis oriented LiNbO
3 film was obtained. The ordinary refractive index of the film became 2.28 at 632.8 nm of wavelength, which coincided with that of a LiNbO
3 single crystal. RHEED observation showed the film had twin boundaries. Further improvements are now undergoing.
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Katsuyasu TAMAOKA, Koichi ENOKI, Yoshifumi AOI, Eiji KAMIJO
1999 Volume 42 Issue 3 Pages
265-268
Published: March 20, 1999
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TiN/CrN multi-layer thin films were deposited on type 306 stainless steel and silicon substrate using an arc ion plating system. The structures of multi-layer thin films were controlled by TiN and CrN deposition time and the arc current. The multi-layer thin films were evaluated with x-ray diffraction and micro-hardness test. The results obtained are as follows : The hardness of deposited multi-layer thin films indicated a maximum value by changing the layer thickness and multi-layer period. The maximum knoop hardness of TiN/CrN multi-layer was found to be about 4, 000 Kg/mm
2. This value was about 1.8 times larger than that of the TiN single layer. The enhancement mechanisms of hardness are discussed.
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Ryuuzou KAMEI, Tatsuo MIGITA, Takeshi TANAKA, Keishi KAWABATA
1999 Volume 42 Issue 3 Pages
269-271
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Tin nitride (SnNx) films were prepared by using an r.f.-d.c. coupled magnetron sputtering system. When an extremely low r.f. power (5 W) and d.c. bias were applied simultaneously to the target, the glow discharge took place at a low d.c. bias of-30 V and the target d.c. current increased smoothly compared with a conventional magnetron sputtering system. It is shown that lowering the target d.c. bias down to-50 V results in an increase of the compositional ratio (N/Sn) up to 0.6 for the SnNx films deposited at the gas flow ratio (N
2/ (Ar+N
2)) of 0.5.
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Nobuo SAITO, Yasuhiro IGASAKI
1999 Volume 42 Issue 3 Pages
272-274
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Indium nitride thin films were prepared by the reactive magnetron sputtering method. The indium target was sputtered by pure nitrogen gas. The effects of sputtering pressure
P on the structural, optical and electrical properties of the films were investigated. With increasing
P, the depo-sion rate of the films decreased, and the film structure changed from crystalline phase with a hexagonal wurtzite structure to amorphous one, together with the increase in the bandgap. It is found that the electrical conductivity, carrier concentration and Hall mobility showed minimum against
P.
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Tetuya KAMASAKA, Naosuke ADATI, Koji INOUE, Masaaki YOSHITAKE, Tadaoki ...
1999 Volume 42 Issue 3 Pages
275-278
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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We developed a new practical thermistor-bolometer type infrared (IR) sensor using a chromium nitride (CrN
x) thin film. CrN
x thin films were prepared by reactive RF magnetron sputtering method. Temperature coefficients of resistance (TCR) of the films were depend on Cr/N composition ratio and the maximum value was-0.8%/°C in CrN
0.9 film.
An IR sensor was integrated into a bridge circuit on a glass substrate of 0.15 mm in thickness. When the surface temperature of an objective changed between-1°C and 59°C, the corresponding output voltage between-45 mV and 63 mV was observed. However, the response time was as slow as 2 sec.
To decrease response time by the thermal capacitance of the IR part, we adopted a diaphragm type substrate of 30 μm in thickness. It was made by etching the back surface of the glass substrate. The resultant response time was improved down to 200 ms, which is fast enough for practical application.
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Toshiaki YASUI, Tomohiro MATSUMOTO, Hirokazu TAHARA, Takao YOSHIKAWA
1999 Volume 42 Issue 3 Pages
279-281
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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A linear sputtering source using electron cyclotron resonance (ECR) plasma was developed for reactive sputter deposition with large area. It is composed of slot antennas on a rectangular waveguide with 268 mm long, 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. A sputtering target is placed within the discharge chamber to achieve high deposition rate. Moreover, this plasma source prevents microwave window contamination by sputtered particles. The spatial uniformity of Ar plasma at 0.146 Pa was ± 7.8% within 180 mm in the long direction. By using Ti target and mixture of Ar and N
2 gases, TiN films were successfully deposited with thickness uniformity of ± 11.3% within 160 mm and deposition rate of 16.2 nm/min.
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Naoki TAKAHASHI, Kouji YANAGISHITA, Toshio HAYASHI, Hitoshi AKIMICHI, ...
1999 Volume 42 Issue 3 Pages
282-285
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The quantitative measurement of partial pressure using a quadrupole mass spectrometer (QMS) is disturbed by the effect of ESD (electron stimulated desorption) ions desorbed from the grid surface of the ionizer. On the other hand, effect of vacuum ultra violet (VUV) photons generated in the ionization process of gasses determines the lower detection limit of the very small amount of impurities in the process gas. To eliminate these effects, we have developed the QMS with a Bessel-Box type energy filter which in placed between the ionizer and the quadrapole mass assembly. The features of the new QMS are as follows : (1) The gas phase ions generated in the ionizer can only be detected. (2) The background signal is suppressed to the level where the minimum detectable impurity in the process gas is less than 10 ppb. From these features, it is expected that the new QMS is also available for the partial pressure measurement in the systems containing high energy particles and photons, such as storage ring systems.
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Tamotsu MAGOME, Katsuyuki FUKUTANI, Tatsuo OKANO
1999 Volume 42 Issue 3 Pages
286-289
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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A state-selective thermal desorption method was developed for the study of the rotational state dependence of adsorption-desorption kinetics of hydrogen molecules. The apparatus consisted of an adsorption-cell cooled by a compressortype cryohead and an ion detection system adopting a (2 +1) resonance-enhanced multiphoton ionization (REMPI) scheme. Granular activated alumina contained in the inner side of the adsorption-cell was used as an adsorbent for the hydrogen molecules. The sorvent was degassed at 523 K for 10 hours in ultrahigh vacuum. After cooling the cell to 14 K, normal hydrogen was admitted at a pressure of 6-8 × 10
-3 Pa for 70 s. Assuming first order kinetics of desorption, desorption energies for hydrogen molecules in the rotational states J=0 and 1 were evaluated as 95 and 110 meV, respectively. These values are consistent with a model that relates the helicopter motion (Jz =± 1) of ortho hydrogen molecules to the higher desorption energy.
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Michiko YOSHITAKE, Kazuhiro YOSHIHARA
1999 Volume 42 Issue 3 Pages
290-292
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The characteristic features of segregation phenomenon of a substrate element on a deposited film on the substrate bring the self-controlling property of surface composition. This property is advantageous to fabricate material to obtain constant work function. The change of work function and binding energy was measured when Cu segregated on Ti surface and Ti on Cu surface. The work function decreased approximately 0.3 eV by Cu segregation on Ti, while it increased approximately 0.2 eV by Ti segregation on Cu. The binding energy of Cu in both specimens was higher that that of pure Cu, which suggested that an electron of Cu was partially transferred to Ti in both cases. The charge transfer resulted in an electric dipole on the surface with the opposite direction for two cases : a positive charge towards vacuum in Cu segregation and a negative charge in Ti segregation. Those dipoles explain the above work function change in both cases.
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Wen Biao YING, Yusuke MIZOKAWA, Toshikazu HAMADA, Katsuto TANAHASHI, Y ...
1999 Volume 42 Issue 3 Pages
293-296
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The room temperature oxidation of heavily P-doped Si (100) prepared by HF-treatment has been monitored for a period of about one year, using angle dependent x-ray photoelectron spectroscopy (XPS) and atomic force microscope (AFM). Right after HF-treatment, the P/Si atomic ratio increased with decreasing the photoelectron take-off angle, which implies that the more segregated-P existed in near the top surface region. In case of the heavily P-doped sample, the chemical composition of the growing oxide films showed that not the Si
4+ but Si
3+ state was dominant component until the oxide thickness went up to over 1.5 nm, while the Si
4+ was the major species for the moderately doped Si (100), except the oxide thickness was less than 0.5 nm. In contrast to the smooth AFM image of moderately doped Si (100) surface, the heavily P-doped Si (100) showed very unique geometrical pattern.
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Yutaka IKEDO, Kazuhiro KIJIMA, Hirokazu HORI, Eiko TORIKAI
1999 Volume 42 Issue 3 Pages
297-300
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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We are developing a new experimental method for studying surface magnetism through spin-dependent scattering of a spin polarized and energy-tunable cesium (Cs) atomic beam at surface. We report the basic concept of the experiment, characteristics of the experimental setup and the sample preparation.
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Hiroaki OOHASHI, Hideki TANAKA, Haruyuki SANO, Goro MIZUTANI, Sukekats ...
1999 Volume 42 Issue 3 Pages
301-304
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The reflected optical second harmonic generation from the interface between Ge (111) and germanium oxide layers has been measured in dry nitrogen atmosphere as a function of the sample rotation angle around its surface normal. The germanium oxide layer was produced either by oxidizing the Ge (111) substrate in air at room temperature (natural oxidation) or by oxidizing the Ge (111) substrate in pure oxygen gas at 823 K (thermal oxidation). A difference was found in the SH intensity in
p-in/
p-out polarization configuration between the Ge/native-oxide interface and the Ge/ thermal-oxide interface. By XPS measurement, we found that GeO and GeO
2 were formed at the Ge (111) /nativeoxide interface and at the Ge (111) /thermal-oxide interface, respectively. We conclude that the difference in the interface structure has led to the difference in the SH intensity pattern.
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Yasuhito GOTOH, Toshiyuki URA, Masayoshi NAGAO, Hiroshi TSUJI, Junzo I ...
1999 Volume 42 Issue 3 Pages
305-308
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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We have prepared niobium nitride thin films by ion beam assisted deposition technique, and investigated the film properties from a viewpoint of cathode material for vacuum microelectronics. Substrate temperature and ion-atom arrival rate ratio were selected as deposition parameters. It was shown nitrogen composition was controlled by ion-atom arrival rate ratio and crystalline of mononitride or subnitride were formed in accordance with the nitrogen composition. Work function decreased with an increase in the nitrogen composition and endurance against the low energy argon ion bombardment improved with an increase in the nitrogen composition. The results would be summarized that the mononitride is the preferred composition.
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Yasuhito GOTOH, Masayoshi NAGAO, Toshiyuki URA, Hiroshi TSUJI, Junzo I ...
1999 Volume 42 Issue 3 Pages
309-312
Published: March 20, 1999
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Electron emission characteristics of niobium nitride field emitter arrays were investigated as a function of nitrogen composition of niobium nitride. Field emitter arrays with 1024 tips were fabricated by depositing niobium nitride onto the silicon field emitter array, which was fabricated by photolithography and wet etching technique. The electron emission characteristics such as current-voltage characteristics and current fluctuation were measured in ultra high vacuum. The results showed that the field emitter array with mononitride showed lower effective work function and lower current fluctuation. The present results indicated that stoichiometric niobium nitride is preferred composition for field emission cathodes of vacuum microelectronics.
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Takanori AOKI, Hideki KAIMI, Akio SUZUKI, Tatsuhiko MATSUSHITA, Masahi ...
1999 Volume 42 Issue 3 Pages
313-316
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The Ga-In oxide films (100150 nm) have been deposited on glass and quartz substrates by irradiating the pulsed laser beam of an ArF laser (λ=193 nm) on the split target composed of Ga
2O
3 and In
2O
3 (99.999% purity). In all experiments, a repetition rate of 10 Hz, an energy density of 0.4 J/cm
2, an irradiation time of 12-15 min (7200-9000 shots) and a target-to-substrate distance of 4 cm were used. It was found from optical spectra that for the Ga-In oxide films prepared with a moved distance of Ga
2O
3 : In
2O
3=3 : 1 on the split target, there was a difference in the transmittance of greater than 66% near 350 nm wavelength, between the annealed (transparent, Eg
opt= 4.2 eV) and the asdeposited state (opaque, Eg
opt= 2.0 eV). The ability to record on the Ga-In oxide films without a protection layer, using THG of Nd : YAG (λ= 355 nm, 3 ns) was confirmed. These results will be useful for highly sensitive optical recording films with high density in the ultraviolet-blue wavelength region.
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Takanori AOKI, Hideki KAIMI, Akio SUZUKI, Tatsuhiko MATSUSHITA, Masahi ...
1999 Volume 42 Issue 3 Pages
317-320
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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Thin films of Ga-In oxide (100 nm) have been deposited, at an Ar pressure of 4 Pa, on glass substrate at room temperature by radio-frequency (rf) magnetron sputtering with two targets of Ga
2O
3 and metallic In, on which rf-power of 150 W and 60 W were added respectively. In the oxide films prepared by this method, the difference in the transmittance, ΔT, between the annealed (300°C × 10 min) and the as-deposited state was more than 60% in the wavelength region of 350600 nm. It was found from XRD spectra that (1) the In (101) peak was formed in the as-deposited state (colored state) and (2) the In
2O
3 (222) peak was formed in the annealed state (transparent state). The ability to record on these oxide films without protection layer, using THG of Nd : YAG laser (λ=355 nm, 3 ns) was confirmed. These results will be useful for highly sensitive optical recording films with high density in the ultraviolet-blue wavelenght region.
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Akio SUZUKI, Hiroaki ISHIDA, Masanari FURIKI, Takanori AOKI, Tatsuhiko ...
1999 Volume 42 Issue 3 Pages
321-324
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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This paper describes transparent conducting ZnO-based thin films prepared using split targets by a pulsed laser deposition technique with an ArF excimer laser (λ=193 nm). The split targets were prepared by combining ZnO with In
2 O
3 or Ga
2O
3. The film with a thickness of 167 nm grown at oxygen flow rate of 3 sccm at a substrate temperature of 350°C, with a tracing ratio of ZnO : In
2O
3 = 1 : 4, showed the lowest resistivity of 4.55 × 10
-4 Ω · cm and an averaged transmittance of 87% in the visible wavelength region. The film (150 nm) grown under the same preparation conditions using the target combined ZnO with Ga
2O
3, with a tracing ratio of ZnO : Ga
2O
3 = 5.3 : 1, showed the lowest resisitivity of 3.35 × 10
-4 Ω · cm and an averaged transmittance of 90% in the visible wavelength region. The optical energy gaps were estimated by plotting the relationship of the direct transition type, (αhν)
2 vs hν using the optical transmission spectra. The crystal orientation and compositions of the films were evaluated by XRD and EDX respectively. It was found from these results that the film preparation using split targets is useful to control the compositions of the ZnO : In
2O
3, and ZnO : Ga
2O
3 films.
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Akio SUZUKI, Masami FUJITA, Kazuhiro HASHIMOTO, Takanori AOKI, Tatsuhi ...
1999 Volume 42 Issue 3 Pages
325-328
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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The split target composed of Ga
2O
3 and In
2O
3 was used to deposit transparent conducting Ga-In oxide thin films on glass substrate by a pulsed laser deposition technique using an ArF laser (λ=193 nm). In all experiments, a repetition rate of 1-20 Hz, an energy density of 0.4-2 J/cm
2, and irradiation time of 20-300 min were used. An optical transmittance of more than 80% in the wavelength region of 380-2700 nm and the lowest resisitivity of 6.96 × 10
-4 Ω · cm, attributing to a high Hall mobility of 52.4 cm
2/V · s and a low carrier concentration of 1.71 × 10
20 cm
-3 were obtained for the 100-150 nm thick Ga-In oxide film with 23.3 wt% Ga content grown in oxygen at substrate temperature of 350°C. The optical energy gap was estimated to be 4.0 eV (310 nm) by plotting the relationship of the direct transition type. The surface morphology packed densely with the ellipsoidal crystallites of axis length of 100-150 nm equal to film thickness was observed by high-resolution SEM.
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Akio SUZUKI, Yoshitaka YONEYAMA, Shinobu OKANISHI, Takanori AOKI, Tats ...
1999 Volume 42 Issue 3 Pages
329-332
Published: March 20, 1999
Released on J-STAGE: October 20, 2009
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About 800-nm-thick ZnO films doped with 4 wt% Ga
2O
3 (GZO films) have been deposited on glass and quartz substrates by a pulsed laser deposition method using Second-Harmonic-Generation (SHG) of Nd : YAG laser (λ =532 nm). In all experiments, a repetition rate of 10 Hz, energy densities of 0.12.5 J/cm
2, and irradiation times of 23 h were used. Scanning-Electron-Microscope (SEM) observations of the film surface revealed that there were micro-textured structures (0.51 μm in diameter) surrounded by small rugged and irregular structures (250400 nm in size). It was recognized from XRD spectra that a strong peak of (103) planes reflected from the micro-textured milky surfaces is dominant. A haze ratio of 46.6% was obtained at a wavelength of 550 nm for about 800-nm-thick GZO (4 wt%) films grown at substrate temperature of 300°C in oxygen with a flow rate of 3 sccm. The lowest resisitivity of 2.33 × 10
-4 Ω· cm and the lowest sheet resistance of 2.72 Ω/sq were obtained for these GZO (4 wt%) films.
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