Polysilicon thin film process and product

Abstract From the Canadian patent

Polycrystalline silicon is deposited in a film onto the surface of a substrate which has been carefully prepared to eliminate any defects or contaminants which could nucleate crystal growth on the substrate. The deposition is carried out by low pressure decomposition of silane at substantially 580°C to cause a film of fine grained crystals of polysilicon to be formed having grain sizes averaging less than about 300 Angstroms after annealing. Such a film is very uniform and smooth having, a surface roughness less than about 100 Angstroms RMS. Annealing of the film and substrate at a low temperature results in a compressive strain in the field that decreases over the annealing time, annealing …