First-principles calculations were performed with regard to dopant-related complexes. Cluster models with localized basis functions were used to calculate spin distributions, while super-cell calculations were used to determine the relative stabilities as a function of the chemical potential. It was shown that a divacancy which captured a P atom gave rise to a deep donor level, and an estimate for the occupancy level was obtained. On the basis of the calculated spin distribution on P at the Si site next to a C vacancy, PSi+VC, the complex was identified with the P-V electron paramagnetic resonance centre. At high Si/C ratios, the formation energies of P at the C site and at the Si site were about the same under thermal equilibrium. The PC was also an effective mass donor in 3C-type material. It was established that substitutional B chose the Si site in a divacancy in both the neutral and negative charge states. That is, no bistability occurred. The resultant BSi+VC complex was a deep acceptor with a spin distribution which was very close to that measured by using the ENDOR technique. The acceptor part of the complex was VC; thus explaining why the photoluminescence spectra indicated that the acceptor was on the same sub-lattice as NC.

Dopant-Related Complexes in SiC A.Gali, J.Miró, P.Deák, R.P.Devaty, W.J.Choyke: Materials Science Forum, 2000, 338-342, 795-8