The diffusion of intrinsic defects in 3C-SiC was studied by using an ab initio method based upon density functional theory. The vacancies were shown to migrate on their own sub-lattice. The C split-interstitials and the two relevant Si interstitials, namely the tetrahedrally C-coordinated interstitial and the <110>-oriented split interstitial, were found to be by far more mobile than the vacancies. The metastability of the Si vacancy, which transforms into a vacancy-antisite complex in p-type and compensated material, kinetically suppresses its contribution to diffusion processes. The role of interstitials and vacancies in the self-diffusion was analyzed. Consequences for the dopant diffusion were qualitatively discussed. The analysis emphasized the relevance of mechanisms based upon Si and C interstitials.

Ab Initio Study of the Migration of Intrinsic Defects in 3C-SiC. M.Bockstedte, A.Mattausch, O.Pankratov: Physical Review B, 2003, 68[20], 205201 (17pp)