Defect levels in the n-type bulk 6H-SiC were investigated by deep level transient spectroscopy and photo-induced transient spectroscopy. From the deep-level transient spectra, 4 electron traps at Ec-0.53eV (T1), Ec-0.64eV (T2), Ec-0.67eV (T3) and Ec-0.69eV (T4) with concentrations of 6.4 x 1015, 1.1 x 1016, 3.0 x 1016 and 1.6 x 1016/cm3, respectively, were revealed. The centres T1, tentatively identified with C vacancies, were found to be located in the vicinity of dislocations. The centres T2 and T3 were assigned to the known deep-level defect Z1/Z2 occurring both in 4H and 6H SiC polytypes. The photo-induced transient spectroscopy measurements revealed 2 shallow traps with activation energies 20 and 60meV, as well as a deep trap at 0.66eV. The origin of the first trap still remained unclear. The latter two traps were tentatively identified with a N atom in hexagonal site and a complex involving a B atom and Si antisite, respectively.

Investigation of Defect Levels in 6H-SiC Single Crystals. P.Kamiński, R.Kozłowski, M.Kozubal, M.Miczuga, M.Palczewska, M.G.Pawłowski, M.Pawłowski: Physica Status Solidi C, 2007, 4[8], 2967-71