It was noted that the epitaxial carbide was likely to contain H and vacancies and that, therefore, V + nH complexes were likely to affect its properties. By using ab initio calculations, it was shown that neutral and positive H atoms were trapped by C vacancies into 3-center bonds with two Si neighbors. The doubly-positive charge state of VC + H was not in stable equilibrium and, in the triply-positive state, H was bound to only one of the Si neighbours. Two H atoms at most could be accommodated by a single VC. The VC + nH complexes had a donor character, and exhibited atypical vibration modes for Si-H bonds.

Over-Coordinated Hydrogens in the Carbon Vacancy - Donor Centers of SiC A.Gali, B.Aradi, P.Deák, W.J.Choyke, N.T.Son: Physical Review Letters, 2000, 84[21], 4926-9