An investigation was made of the atomic configurations, stabilities, and electronic structures of the C-H complex in various charge states. This was based upon the use of the pseudopotential density-functional method in a super-cell geometry. In the case of the neutral and positive charge states, it was found that the bond-interstitial site between a substitutional C atom and the adjacent Si atom was most stable for H. The anti-bonding sites of C and Si were metastable. In the negative charge state, the tetrahedral interstitial site, in which the H was dissociated from the C, was as stable as the bond-interstitial site for H. The impurity states which were due to the complex, apart from the state in the anti-bonding C configuration, were virtually identical to those due to a H atom at the same atomic sites, without C.

C.Kaneta, H.Katayama-Yoshida: Materials Science Forum, 1995, 196-201, 897-902