Dopant diffusion and defect formation were studied as a function of implantation temperature in Si-implanted material. It was found that the diffusion of Si during post-implantation annealing decreased by a factor of 2.5 as the implantation temperature was increased from -2 to 40C. Within the same temperature range, the maximum depth and density of extrinsic dislocation loops increased by factors of 3 and 4, respectively. Rutherford back-scattering channelling measurements indicated that Si-implanted GaAs underwent an amorphous to crystalline transition at Si implantation temperatures of between -51 and 40C. A unified explanation was proposed, for the effects of implantation temperature upon diffusion and dislocation formation, which was based upon known differences in sputter yield between crystalline and amorphous semiconductors. The model assumed that the sputter yield was enhanced by amorphization at lower temperatures; which increased the excess vacancy concentration. Estimates of the latter were obtained by simulating the diffusion profiles, and were found to be quantitatively consistent with sputter yield enhancement.

H.G.Robinson, T.E.Haynes, E.L.Allen, C.C.Lee, M.D.Deal, K.S.Jones: Journal of Applied Physics, 1994, 76[8], 4571-5