An analysis, by means of first-principles electronic structure calculations, was made of the structural, energetic and diffusive properties of B impurities as well as vacancies. The study focused upon determining the equilibrium structures of the impurity in the lattice, by means of structural relaxation calculations, and upon elucidating the energy profile along a possible diffusion path determined by means of constrained relaxations. A study was also made of the diffusion mechanisms that were relevant to the migration of Si and C vacancies; characterizing the barriers to the various processes. Competition between 2 possible diffusion paths for the Si vacancy was considered. One involved only the Si sub-lattice, and one involved both C and Si sites. The effect of the charge state of the defects upon the barrier shape and height was explicitly taken into account.

First-Principles Studies of the Diffusion of B Impurities and Vacancies in SiC. R.Rurali, E.Hernández, P.Godignon, J.Rebollo, P.Ordejón: Physical Review B, 2004, 69[12], 125203 (11pp)