Several different electron paramagnetic resonance spectra were observed in Sc-doped 6H and 4H epitaxial layers. Several of those observed in 6H-material had been measured previously. In the case of 6H-material, all of the spectra exhibited a pronounced temperature dependence, together with a 45Sc hyperfine interaction pattern. The spectra were explained as being due to the isolated Sc0 (S = 1/2) acceptor on inequivalent C sites, but with differing microscopic configurations. At low temperatures, the hole of the Sc0 acceptor was located either along the c-axis, so as to form an axial centre, or along one of the 3 other C-Si bonds, so as to give rise to a monoclinic centre. At higher temperatures, the hole changed places rapidly between the three C-Si bonds; resulting in an axial centre. All three Sc0 hole configurations had differing ionization levels. In 4H-material, only spectra from a single Sc centre with monoclinic symmetry were observed.

Electron Paramagnetic Resonance of the Scandium Acceptor in 6H and 4H Silicon Carbide M.März, S.Greulich-Weber, J.M.Spaeth, E.N.Mokhov, E.N.Kalabukhova: Semiconductor Science and Technology, 2000, 15[1], 55-60