Optically detected magnetic resonance methods were used to study defects in n-type material. Four spectra were observed which were related to spin S = 1 centres. Two of these centres, labelled a and b, had trigonal symmetry with the symmetry axis lying along the c-axis of the hexagonal crystal. For the other two centres, labelled c and d, the symmetry was lower (C1h) and the principal axis of the g and D tensors was about 71º off the c-axis. On the basis of the symmetry axes, the annealing behaviour and the intensity, the spectra were suggested to originate from various configurations of the paired centre between a Si vacancy and a nearest-neighbour point defect (C vacancy or Si antisite) which occupied different inequivalent sites in the material. These defects were non-radiative, and acted as efficient recombination channels.

Optically Detected Magnetic Resonance Studies of Intrinsic Defects in 6H-SiC N.T.Son, P.N.Hai, M.Wagner, W.M.Chen, A.Ellison, C.Hallin, B.Monemar, E.Janzén: Semiconductor Science and Technology, 1999, 14[12], 1141-6