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Structural characterization of amorphous silicon nitride by molecular dynamics simulation

1992; Elsevier BV; Volume: 150; Issue: 1-3 Linguagem: Inglês

10.1016/0022-3093(92)90107-u

1873-4812

Norimasa Umesaki, Naoto Hirosaki, Kazuyuki Hirao,

Semiconductor materials and devices

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.