Eur. Phys. J. B 38, 437-444 (2004)
https://doi.org/10.1140/epjb/e2004-00137-6

Energetics of native point defects in cubic silicon carbide

INFM and Department of Physics University of Cagliari, Cittadella Universitaria, 09124 Monserrato (CA), Italy

Corresponding author: ^a luciano.colombo@dsf.unica.it

Received: 9 January 2004
Published online: 28 May 2004

Abstract

In this work we present a detailed investigation of native point defects energetics in cubic SiC, using state-of-the-art first principles computational method. We find that, the carbon vacancy is the dominant defect in p-type SiC, regardless the growth conditions. Silicon and carbon antisites are the most common defects in n-type material in Si-rich and C-rich conditions respectively. Interstitial defects and silicon vacancy are less favorite from the energetic point of view. The silicon vacancy tends to transform into a carbon vacancy-antisite complex and the carbon interstitial atom prefers to pair to a carbon antisite. The dumbbell structure is the lowest-energy configuration for the isolated carbon interstitial defect, and the tetrahedral interstitial silicon is a stable structure in p-type and intrinsic conditions, while in n-type material the dumbbell configuration is the stable one. Our results suggest that, in samples grown in Si-rich stoichiometric conditions, native defects are a source of n-doping and of compositional unbalance of nominally intrinsic SiC, in accord with experimental evidence.