Electron paramagnetic resonance was used to study defects in p-type 4H and 6H material which had been irradiated with 2.5MeV electrons at 400C. After irradiation, an anisotropic electron paramagnetic resonance spectrum with monoclinic symmetry (C1h) and an effective spin of S = 1 was observed in both materials. The same g-tensor, and same principal values, was determined for the spectra from both polytypes. The z-axis and the x-axis lay in the (11•0) plane, with the y-axis perpendicular to this plane. The angle between the principal z-axis and the c-axis was 54º. It was deduced, from the 29Si hyperfine structure and the spin Hamiltonian parameters, that the defect consisted of a pair of C vacancies on (11•0) or equivalent planes.

The Carbon Vacancy Pair in 4H and 6H SiC N.T.Son, P.N.Hai, A.Shuja, W.M.Chen, J.L.Lindström, B.Monemar, E.Janzén: Materials Science Forum, 2000, 338-342, 821-4