The effect of the annealing ambient upon dopant diffusion was studied, during low-temperature processing by implanting P into (100) samples (at room temperature) through a 14nm SiO2 layer. The implantation dose and energy were sufficient to amorphize the surface. After low-temperature furnace annealing, the ion-implanted P exhibited a transient enhanced diffusion regime for both inert and oxidizing ambients. It had been expected that point defect generation during the annealing of implantation damage would predominate during the transient enhanced diffusion process; regardless of the nature of the ambient. Deeper P junctions were found, for implants which had been annealed in an oxidizing ambient, when surface oxidation had consumed more than 5nm of the Si. It was suggested that stress in the surface layer played an important role in the diffusion of high-dose P implants. Oxidation tended to consume this highly stressed surface layer, which could suppress P diffusion in the tail region.

Y.Kim, H.Z.Massoud, R.B.Fair: Journal of the Electrochemical Society, 1990, 137[8], 2599-603