Atomic-scale computer simulations, both molecular dynamics and the nudged-elastic band methods, were applied to investigate long-range migration of point defects in cubic SiC (3C-SiC) at homologous temperatures ranging from 0.36 to 0.95. The point defect diffusivities, activation energies, and defect correlation factors were obtained. Stable C split interstitials could migrate via the first- or second-nearest-neighbor sites, but the relative probability for the latter mechanism was very low. Si interstitials migrate directly from one tetrahedral position to another neighboring equivalent position by a kick-in/kick-out process via a split-interstitial configuration. Both C and Si vacancies jump to one of their equivalent sites through a direct migration mechanism. The migration barriers obtained for C and Si interstitials were consistent with the activation energies observed experimentally for two distinct recovery stages in irradiated SiC. Also, energy barriers for C interstitial and vacancy diffusion were in reasonable agreement with ab initio data.

Atomistic Study of Intrinsic Defect Migration in 3C-SiC. F.Gao, W.J.Weber, M.Posselt, V.Belko: Physical Review B, 2004, 69[24], 245205 (5pp)