Ion channelling and cross-sectional transmission electron microscopic techniques were used to study the extent and nature of Si ion implantation damage in epitaxial GaN layers at liquid N temperatures. The results indicated that the displacement damage which was produced by implantation exhibited a substrate dynamic annealing behavior during implantation. Consequently, the residual implantation damage at moderate implantation doses consisted of a dense network of secondary defects (clusters, loops) which were the result of an incomplete annihilation of implantation-produced defects. Amorphous layers could be produced, but the required doses were greater than 1016/cm2 and amorphization appeared to begin at the surface.

H.H.Tan, J.S.Williams, J.Zou, D.J.H.Cockayne, S.J.Pearton, R.A.Stall: Applied Physics Letters, 1996, 69[16], 2364-6