The authors investigated the application of the carbon-implantation/annealing method for the annealing of the main lifetime limiting defect Z1/2 in thick 4H–SiC epilayers. Examination of different implantation doses and annealing temperatures showed that finding the optimum conditions was crucial for obtaining thick layers with carrier trap concentration below 1011/cm3 in the whole 100µm epilayer. The carrier lifetime increased from less than 200ns to over 1µs at room temperature in the samples annealed with the carbon-implanted layer. The thick 4H–SiC epilayers after the application of the carbon-implantation/annealing were confirmed to be applicable for fabrication of high-voltage bipolar devices and resulted in improved conductivity modulation. Possible annealing mechanisms were discussed in detail making a comparison between annealing of as-grown material and irradiated material.

Enhanced Annealing of the Z1/2 Defect in 4H–SiC Epilayers. L.Storasta, H.Tsuchida, T.Miyazawa, T.Ohshima: Journal of Applied Physics, 2008, 103[1], 013705