The metastability of vacancies was theoretically predicted for several compound semiconductors together with their transformation into the antisite-vacancy pair counterpart. It was noted that no experiment had so far unambiguously confirmed the existence of such antisite-vacancy pairs. By using electron paramagnetic resonance and first-principles calculations the S15 center was identified as being the C antisite-vacancy pair in the negative charge state, CSiVC, in 4H-SiC. It was suggested that this defect was a strong carrier-compensating center in n-type or high-purity semi-insulating SiC.

Identification of the Carbon Antisite-Vacancy Pair in 4H-SiC. T.Umeda, N.T.Son, J.Isoya, E.Janzen, T.Ohshima, N.Morishita, H.Itoh, A.Gali, M.Bockstedte: Physical Review Letters, 2006, 96[14], 145501