It was recalled that deep-level transient spectroscopy signals, attributed to centers labelled H1, H2, H3 and E2, were long ago detected in neutron-irradiated 3C-type material. The H centers were believed to be the primary point defects, with the E2 center being a secondary defect which formed after the H centers began to migrate. Computational evidence was presented here which suggested that the H centers were due to Si antisite defects (SiC). In both the cubic (3C) and hexagonal (2H) polytypes, the Si antisite had several ionization levels in the band-gap. The positions of these ionization levels in 3C-type material were calculated accurately by using the plane-wave pseudopotential method and a 128-atom super-cell. Very good agreement with experimental data was found, and indicated that the H centers were due to the formation of SiC during neutron irradiation. The formation energies and local geometries of antisite defects were also predicted.

L.Torpo, S.Pöykkö, R.M.Nieminen: Physical Review B, 1998, 57[11], 6243-6