In SiC, mobile point defects may form thermally stable clusters and aggregates, such as di-vacancies or C interstitial complexes. Although predicted by theory, experimental evidence of such clusters became available only recently. Combining theoretical and experimental approaches, the unique identification of the di-vacancy, the C vacancy-antisite complex with the spin resonance centers P6/P7 and SI5 was recently achieved. In this way, the di-C and tri-C antisites with the photoluminescence centers P-T and U, HT3 and HT4, respectively, were also identified. The two identified vacancy complexes exhibited distinct properties: while the di-vacancy, like the Si vacancy possessed a high-spin ground state, the C vacancy-antisite complex, like the C vacancy, was a Jahn-Teller center. These effects consistently explained the complex properties of the spin resonance spectra and were considered in detail for the isolated vacancies. The aggregation of vacancies proved to be relevant in the explanation of the kinetic deactivation of N in co-implanted SiC.

Identification of Intrinsic Defects in SiC - Towards an Understanding of Defect Aggregates by Combining Theoretical and Experimental Approaches. M.Bockstedte, A.Gali, A.Mattausch, O.Pankratov, J.W.Steeds: Physica Status Solidi B, 2008, 245[7], 1281-97