Vol. 50, No. 1 (2001)
2001-01-05
GENERAL
ATOMIC AND MOLECULAR PHYSICS
CLASSICAL AREA OF PHENOMENOLOGY
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
研究论文
2001, 50 (1): 83-87.
doi: 10.7498/aps.50.83
Abstract +
The influence of substrates on the formation of cubic boron nitride(c-BN) thin films was reported. The c-BN thin films were deposited on different substrates with hot-filament-assisted plasma CVD and RF sputter. In the CVD method, NH3,B2H6 and H2 were reacting gases and Si,Ni,Co,stainless steel and other materials were substrates. The experiments showed that the cubic phase content in c-BN thin films was affected by substrates. The film on Ni substrate was the best among all the substrates in the CVD method, and its cubic phase content reached over 80%. Our study also found that in the CVD method a Ni interlayer on the Si substrate can improve the quality of the c-BN thin films than directly on Si substrate. In the sputter method, the working gas was N2 and Ar, hot-pressed hexagonal boron nitride(h-BN) of 4N purity was used as sputtering target, the c-BN thin film with over 90% content of cubic phase was successively deposited on Si substrate. In our research, the boron nitride thin films were characterized by Fourier Transform Infrared(FTIR) Spectra and X-ray diffraction.Finally we concluded that for CVD method the cubic phase content and adhesion are highly affected by the crystal lattice mismatch between c-BN and substrate materials; however, for sputter method the crystal lattice mismatch between c-BN and substrate materials little affects the quality of c-BN thin films.
2001, 50 (1): 182-184.
doi: 10.7498/aps.50.182
Abstract +
The process for the formation of the streamwise vortex in a transitional boundary layer is described. A new instability of the vortex tube has been found which can be used to describe the formation of the streamwise vortices. To the author's knowledge the present results have not been reported before.
2001, 50 (1): 185-188.
doi: 10.7498/aps.50.185
Abstract +
SOI-SIMNI (Silicon On Insulator-Separation by Implanted Nitrogen) films were formed by standard and multiplestep implantation methods. The Hal-l effects measurements (4-300K) show that the multiple-step implanted SIMNI films have a lower sheet resistance and higher carrier mobility than those in standard SIMNI films. The DLTS results indicated that there is a deep level defects Et=0.152eV in the standard SIMNI films, and no deep level defects in the multiple-step implanted SIMNI films, which have good electrical properties.
2001, 50 (1): 95-98.
doi: 10.7498/aps.50.95
Abstract +
An ab initio method with mixed-basis norm-conserving non-local pseudopotential has been employed to study the geometry and electronic properties of transition metal aluminide NiAl. The structure-energy phase diagram, band structure, electronic density of states and valence electron charge density contours have been show n. T he crystal structure, lattice constant, bulk modulus and band structures obtained by our calculation are in good agreement with other theoretical results and experimental data.
