Affiliation: | Material Physics Department, Government Industrial Research Institute, Osaka, 1-8-31, Midorigaoka, Ikeda, Osaka 563, Japan Material Research Laboratory, Central Engineering Laboratory, Nissan Motor Co. Ltd., 1, Natsushima-cho, Yokosuka 237, Japan Faculty of Engineering, Kyoto University, Sakyou-ku, Kyoto 606, Japan |
Abstract: | Computer simulation, using the molecular dynamics (MD) technique, has been carried out on amorphous silicon nitride (a-Si3N4) with simple Busing-type potentials. From the MD simulation, the following points have been deduced. (1) The average Si---N bond length obtained from MD results is rSi---N=1.74 Å, and its coordination number, NSi---N, is 3.95. The bond angles around a Si and a N atom, N---Si---N and Si---N---Si, are found to be 109.8° ± 12.36° and 127.08° ± 16.63°, respectively. The N---Si---N value obtained is in very good agreement with the tetrahedral bond angle (= 109.47°). Hence, the short-range structural arrangement of a-Si3N4 comprises tetrahedral SiN4 units. The MD results presented in this study also indicate that there exist only a small number of defects such as dangling bonds. (2) These MD results are in good agreement with the reported X-ray and neutron data. The a-Si3N4 structure can be reproduced by the MD simulation given in this study. |