The stable configurations of H and di-hydrogen defects were established on the basis of ab initio density-functional calculations for super-cells of 3C-type material. The calculated formation energies were used to provide semi-quantitative estimates of the concentration of H following chemical vapour deposition, low-temperature H-plasma annealing, or heat treatment in high-temperature H gas. Vibration frequencies, spin distributions and occupation levels were also calculated in order to facilitate spectroscopic identification of the defects. It was suggested that (V+nH) complexes were the cause of some of the signals which had previously been attributed to pure vacancies. The qualitative extrapolation of the results to hexagonal polytypes was thought to explain the observed electrical passivation effects of H.

Ab initio Density-Functional Super-Cell Calculations of Hydrogen Defects in Cubic SiC. B.Aradi, A.Gali, P.Deák, J.E.Lowther, N.T.Son, E.Janzén, W.J.Choyke: Physical Review B, 2001, 63[24], 245202 (19pp)