The interdependence of the diffusion behavior and grain microstructure in amorphous polysilicon - on - monocrystal systems was studied with regard to the rapid thermal and furnace annealing of BF2 implants. It was found that changes in microstructure during annealing played a major role in determining the diffusion profiles in the substrate as well as in the polysilicon layer. This led to the formation of shallower junctions in the substrate for the first case. There was little difference in the final microstructure and junction depth between the 2 cases. The B junctions which formed in the substrate were found to be very uniform laterally, in spite of expected doping inhomogeneities that were caused by polysilicon grain boundaries, for both as-deposited amorphous Si diffusion sources and for as-deposited polysilicon diffusion sources.

K.Park, S.Batra, S.Banerjee, G.Lux: Journal of Electronic Materials, 1991, 20[3], 261-5