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Volume 41, Issue 5
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Hiromu SHIOMI1998 Volume 41 Issue 5 Pages 499-506
Published: May 20, 1998
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSDiamond possesses the potential for application as a field emitter cathode because of its negative electron affinity. In order to fabricate diamond field emitter devices, the developments of electrical properties and structures of diamond are required.
In terms of the development of electrical properties, conduction mechanism of boron-doped homoepitaxial diamond was investigated by means of Hall measurements and infrared-visble spectroscopy. Diamond films with various boron concentrations were grown by the microwave plasma-assisted CVD method. It is shown that owing to the strong interactions between the hole and the optical phonon, the conduction mechanism changes from a valence-band conduction to an impurity-band conduction in a sample with a carrier concentration of more than 1018 cm-3 at room temperature. This impurity-band conduction can be used as a source of electrons for a field emission.
In terms of the development of device structures, reactive ion etching (RIE) of synthetic Ib diamond and CVD diamond films in O2 and CF4 has been investigated. The large etch rate of up to 2.8μm/hr and etch rate ratios of 15-20 for diamond (100)/Al were obtained at CF4/O2 = 10-20%. Numerous columnar structures of approximately 300 nm length and 10 nm width have been made by etching CVD polycrystalline diamond films in O2 plasma. The structures made the diamond film “porous”. A comparative study of field emission characteristics has been made for as-grown diamond films and porous diamond films. The average turn-on field was in the range of 2-3 V/μm for porous diamond films and 6-8 V/μm for as-grown diamond films.View full abstractDownload PDF (1298K) -
Yoshinao IKEDA, Kazuya SAITO, Sonoko TSUKAHARA, Shingo ICHIMURA, Kiyoh ...1998 Volume 41 Issue 5 Pages 507-511
Published: May 20, 1998
Released on J-STAGE: April 23, 2010
JOURNAL FREE ACCESSCoating of titanium nitride TiN film on stainless steel by hollow cathode discharge method under the controlled conditions has been developed and could reduce outgassing rate at the extremely high vacuum due to the hydrogen barrier effect of TiN.
This paper reports 1. further reduction of hydrogen permeation constant K of TiN film, 2. application of this technique to practical chamber preparation, and 3. reduction of outgassing rate of the resulting chamber.
Hydrogen permeation constant of TiN films prepared by a laboratory equipment was decreased by improving the film structure to more dense and larger grains. The minimum hydrogen permeation constant K of TiN film at 500°C was 6×10-13 Pa1/2·m2·s-1.
Considering the above result, the practical condition of manufactuaring equipment was adjusted to make large samples for new XHV chambers fabricated for standard pressure measurement by Electrotechnical Laboratory in Japan.
The resulting outgassing rate of a TiN coated chamber was measured by switching between two pumping paths (SPP) method at room temperature. At the ultimate pressure the outgassing rates of the stainless steel chamber was 3×10-12 Pa·m·s-1 after the prebaking of (430°C×100 h+ 500°C×100 h) and after TiN coating on the chamber it decreased to less than 1×10-13 Pa·m·s-1, the lowest value obtained for stainless steel.View full abstractDownload PDF (847K) -
Youji TANI, Yoshifumi AOI, Eiji KAMIJYO1998 Volume 41 Issue 5 Pages 512-515
Published: May 20, 1998
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSCarbon nitride films were prepared by electron cyclotron resonance (ECR) sputtering deposition method using a carbon target and a nitrogen atmosphere. The deposited films were evaluated with the x-ray photoelectron spectroscopy, Raman spectroscopy, atomic force microscopy (AFM) and x-ray diffraction. The nitrogen concentration, chemical bonding, surface morphology and structure were clearly dependent on the floating substrate potential, corresponding to the ion irradiation energy onto substrates. The maximum of nitrogen to carbon atomic ratio (N/C) for the film deposited at a floating substrate potential of - 50 V reached to 1.35, which was stoichiometry of C3N4. The XPS N 1 s and Raman spectra indicated that the change of bonding structure occurred with increasing nitrogen concentration in the deposited film. Furthermore micro-crystals were observed with AFM. The x-ray diffraction measurement of the film deposited at 600°C suggests that the lattice parameters of the micro-crystal are similar to the predicted beta and/or alpha C3N4.View full abstractDownload PDF (643K) -
Yukio INOKUTI, Kazuhiro SUZUKI, Osamu OHKUBO, Natsuki TAKAHASHI1998 Volume 41 Issue 5 Pages 516-519
Published: May 20, 1998
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSThe crack morphology and corrosion for TiN and Ti films deposited on stainless steel sheets has been studied. After the bulge-press forming and the corrosion test, scanning electron microscope (SEM) observation were done on the surface and cross-section of films of the central parts of press formed area.
The TiN films showed the comparatively sharp straight cracks characteristic of ceramics, whereas the Ti films cracked in the slightly elongated manner characteristic of metal, with scribing on the surface due to the soft Ti films.
After the corrosion test, the TiN films were corroded remarkably, whereas the Ti films were masked with thin oxides. In particular, the oxides on TiN were different from those on Ti.
It should be noticed that the TiN films were more susceptible to corrosion than the Ti films, presumably because the cavities and oxides created by internal peeling in TiN films exposed a greater area of steel and tended to trap corrosive substances.View full abstractDownload PDF (1142K) -
Akishige SATO, Masaru KITAGAWA, Yasunobu KURODA, Eiji KUSANO, Akira KI ...1998 Volume 41 Issue 5 Pages 520-523
Published: May 20, 1998
Released on J-STAGE: October 20, 2009
JOURNAL FREE ACCESSTiC films have been deposited onto borosilicate glass substrates by reactive magnetron sputtering using C sheets set on a Ti target as a solid carbon source. The composition and structure of films deposited for various source C/Ti ratios have been analyzed by X-ray diffraction (XRD) and by X-ray photoelectron spectroscopy (XPS). The film hardness was measured by nanoindentation. The XRD results showed that the TiC films with a (111) preferred orientation were deposited at the source C/Ti areal ratios over 0.4 and that the d-value of the peaks from α-Ti (002) or TiC (111) increased monotonically with source C/Ti ratio. The XPS results showed that the C contents of the films deposited for the source C/Ti ratios over 0.4 were about 30% and that these films contained oxygen as an impurity. The hardness of the films increased with source C/Ti ratio, yielding a maximum of 11 GPa at a source C/Ti ratio of 0.53.View full abstractDownload PDF (428K)
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