It was found that 240GHz electron paramagnetic resonance measurements of as-grown nominally semi-insulating 4H-SiC detected 2 well-separated centers: ID1 and ID2. The electron paramagnetic resonance parameters of ID1 and ID2 coincided with those of the EI5 and EI6 centers which had previously been detected in 2MeV electron-irradiated p-type 4H-SiC:Al by using 95GHz electron paramagnetic resonance. The defects in irradiated material were attributed to a positively charged C vacancy (EI5) and a Si antisite (EI6), respectively. An increased separation between the 2 centers at 240GHz, and the absence of additional radiation-induced spectral lines in the as-grown un-irradiated SiC, facilitated analysis of the defect structure. The data confirmed that the ID1 center was a C-vacancy related defect, but were not consistent with the attribution of the ID2 center to a Si antisite. The ID2 spectrum was best fitted by another C-vacancy related defect. Illumination with light below 1400nm quenched both ID1 and ID2 simultaneously; thus suggesting that the defect energy levels were almost the same.

240GHz Electron Paramagnetic Resonance Studies of Intrinsic Defects in As-Grown 4H-SiC. V.V.Konovalov, M.E.Zvanut, J.van Tol: Physical Review B, 2003, 68[1], 012102 (4pp)