The implantation of N into {00•1} epilayers of p-type 6H-type material was investigated as a function of the implanted dose. The lattice damage which was introduced by the implantation was characterized by means of Rutherford back-scattering spectroscopy and Raman scattering. It was found that the damage increased markedly when the dose exceeded 1015/cm2, and that amorphous layers formed at doses of more than 4 x 1015/cm2. Upon annealing (1500C), electrical activation ratios of about 50% could be obtained in the case of low-dose implantation (less than 1015/cm2). However, the degree of activation fell sharply with increasing implanted dose. This was attributed to the effect of residual damage in the implanted layers.

T.Kimoto, A.Itoh, H.Matsunami, T.Nakata, M.Watanabe: Journal of Electronic Materials, 1995, 24[4], 235-40