High-purity, semi-insulating 6H-SiC substrates grown by high-temperature chemical vapor
deposition were studied by electron paramagnetic resonance (EPR). The carbon vacancy (VC), the
carbon vacancy-antisite pair (VCCSi) and the divacancy (VCVSi) were found to be prominent defects.
The (+|0) level of VC in 6H-SiC is estimated by photoexcitation EPR (photo-EPR) to be at ~ 1.47 eV
above the valence band. The thermal activation energies as determined from the temperature
dependence of the resistivity, Ea~0.6-0.7 eV and ~1.0-1.2 eV, were observed for two sets of samples
and were suggested to be related to acceptor levels of VC, VCCSi and VCVSi. The annealing behavior of
the intrinsic defects and the stability of the SI properties were studied up to 1600°C.
