Patent ID: 6242278
Filing Date: 2001-06-05
Classification: H01L

Abstract:
In a method for forming a rough surface made of polysilicon grains on an amorphous silicon film disposed on a semiconductor substrate, comprising the steps of:(i) forming an amorphous silicon-polysilicon mixed-phase layer having a first density on an activated surface of the amorphous silicon film by contacting the surface with a gas containing monosilane at a first flow rate of monosilane and at a first temperature; and(ii) annealing the amorphous silicon-polysilicon mixed-phase layer to form polysilicon grains therefrom, thereby forming a rough surface made of polysilicon grains;wherein the improvement comprises, throughout the mixed-phase formation step, using disilane in place of monosilane at a second flow rate lower than the first flow rate and at a second temperature lower than the first temperature to form an amorphous silicon-polysilicon mixed-phase layer having a second density higher than the first density, said second flow rate being 0.01 sccm to 2 sccm, said second temperature being approximately 20.degree. C. lower than the first temperature and being constant in the range of 450-560.degree. C.