The properties of H in 3C and 4H type SiC were studied theoretically at the density functional level. It was found that only singly positive or negative charge states of H were thermodynamically stable in SiC. The transition from the positive to the negative charge state (+/–) was at 0.9 and 1.3eV above the valence band maximum in 3C and 4H structures, respectively. The diffusion barrier for the proton was 0.5eV (being, however, anisotropic in 4H). For the negative H– the diffusion barrier was found to be considerably higher, of the order of 3eV.

Interstitial H and H2 in SiC. M.Kaukonen, C.J.Fall, J.Lento: Applied Physics Letters, 2003, 83[5], 923-5