Native Defects in Diamond, Sic, and Si: Energetics and Self-Diffusion

Abstract

AbstractWe have investigated, via first principles total energy calculations, the energetics of elementary native defects in group IV semiconductors. Its implications on the relative abundance of these defects and self-diffusion phenomena are analyzed. The results show that in diamond the self-diffusion is dominated by vacancies, because the interstitial and direct exchange mechanisms have much greater activation energy. In SiC stoichiometry plays an important role. For Si-rich compound, Sic-antisite is the dominant defect in the intrinsic and p-type material, while the carbon vacancy is dominant in the n-type material. For C-rich material, the Csi-antisite is dominant regardless the position of the Fermi level. In Si, it well-known that the vacancy, interstitial and direct exchange mechanisms have very similar activation energies. Our results suggest that self-diffusion experiments carried out at various pressures can determine the relative contribution of each of these mechanisms.