It was recalled that implantation damage was believed to play a significant role in dopant diffusion. An attempt was made here to modify the point defect damage profile of 40keV 29Si implants by chemically etching away the top 10nm of the sample after implantation. No Si diffusion was observed in these samples after annealing, whereas significant Si redistribution occurred in a similar sample which had received no post-implantation etching. The results of TRIM simulations predicted an excess Ga vacancy surface layer, and the presence of excess Ga interstitials deeper within the sample. It was thought that, by removing the vacancy-rich surface layer, the etch altered the implant damage profile and thus the diffusion behavior of Si. The surface effects of etching which were related to Si diffusion were shown to be consistent with a vacancy-assisted diffusion mechanism. There was some evidence that this model might be applicable to B implants in Si.

C.C.Lee, M.D.Deal, J.C.Bravman: Applied Physics Letters, 1994, 64[24], 3302-4