The annealing kinetics of mobile intrinsic defects in cubic SiC was investigated by using an ab initio method based upon density-functional theory. The interstitial-vacancy recombination, the diffusion of vacancies, and interstitials to defect sinks (e.g., surfaces or dislocations) as well as the formation of interstitial clusters were considered. The calculated migration and reaction barriers suggested a hierarchical ordering of competing annealing mechanisms. The higher mobility of C and Si interstitials as compared to the vacancies drives the annealing mechanisms at lower temperatures including the vacancy-interstitial recombination and the formation of interstitial C clusters. These clusters act as a source of C interstitials at elevated temperatures. In p-type material the transformation of the Si vacancy into the more stable vacancy-antisite complex constitutes an annealing mechanism which was activated before the vacancy migration. Recent annealing studies of vacancy-related centers in irradiated 3C-SiC and 4H-SiC and semi-insulating 4H-SiC were interpreted in terms of the proposed hierarchy of annealing mechanisms.

Ab initio Study of the Annealing of Vacancies and Interstitials in Cubic SiC - Vacancy-Interstitial Recombination and Aggregation of Carbon Interstitials. M.Bockstedte, A.Mattausch, O.Pankratov: Physical Review B, 2004, 69[23], 235202 (13pp)