Deep-level transient spectroscopy was used to study defect energy levels in N-doped 6H-type epitaxial layers which had been irradiated with 2MeV electrons and implanted with 300keV D or H at room temperature. The same levels appeared in various samples which had been grown by chemical vapor deposition. This showed that they were due to characteristic defects in n-type 6H epitaxial layers. It was suggested that a Ec-0.51eV level originated from a C vacancy, and that levels at Ec-0.34, Ec-0.41 and Ec-0.51eV were different charge states of the C vacancy. The annealing kinetics of a Ec-0.51eV level were first-order, with an activation energy of 1.45eV. A level at Ec-0.87eV was suggested to arise from a vacancy-impurity complex. The results for the Ec-0.62 and Ec-0.64eV levels were consistent with a defect model which involved a Si vacancy on inequivalent sites in the 6H lattice. The present results showed that, at H doses of 1011/cm2, no interaction occurred between H and irradiation-induced Si vacancies; even after annealing at temperatures of up to 800C.

Defect Energy Levels in Electron-Irradiated and Deuterium-Implanted 6H Silicon Carbide M.O.Aboelfotoh, J.P.Doyle: Physical Review B, 1999, 59[16], 10823-9