Identification of intrinsic defects in SiC: Towards an understanding of defect aggregates by combining theoretical and experimental approaches

In SiC, mobile point defects may form thermally stable clusters and aggregates, such as di-vacancies or carbon 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 carbon vacancy-antisite complex with the spin resonance centers P6/P7 and SI5 was recently achieved. In this way also the di-carbon and tri-carbon antisites with the photoluminiscence centers P-T and U, HT3 and HT4, respectively were identified. The two identified vacancy complexes show distinct properties: while the di-vacancy, like the silicon vacancy possesses a high-spin ground state, the carbon vacancy-antisite complex, like the carbon vacancy, is a Jahn-Teller center. These effects consistently explain the complex properties of the spin resonance spectra and are discussed in detail for the isolated vacancies. The aggregation of vacancies proved to be relevant in the explantation of the kinetic deactivation of nitrogen in co-implanted SiC. This and further evidence for defect aggregates underline the relevance of this motion. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.