Radiation induced defects in 3C-SiC and their annealing behavior

Electron spin resonance (ESR) was used to study radiation induced defects in CVD-grown 3C-SiC. Four new ESR-signals labeled T1, T5, T6, and T7 were found for the first time in 1MeV electron and 2MeV proton irradiated 3C-SiC epilayers. Analysis of ESR-line intensity and angular dependence of these signals by using spin Hamiltonian showed that the T1 and T5 signals arise from a negatively charged vacancy at a silicon sublattice site (spin state S=3/2, Td symmetry) and a positively charged vacancy at a carbon sublattice site (spin state S=1/2, D2 symmetry), respectively. It was also found that the T6 and T7 are attributable to vacancy-interstitial pairs (spin state S=1). Isochronal annealing of irradiated 3C-SiC epilayers indicated that the T1 center had three annealing stages of 150degC, 350degC, and 750degC, and that the T5, T6, and T7 centers were annealed at stages of 150degC, 300degC, and 300degC, respectively. (author)