A study of the effect of in situ doping on the crystallinity of LPCVD polysilicon

Results are presented for the degree of crystallinity, determined by Raman spectroscopy, of in situ B doped LPCVD polysilicon as a function of deposition temperature. The results are compared with those reported in the literature for P doped polysilicon and it is found that for B doping full crystallinity of the layer is achieved at a significantly lower deposition temperature than is required for P doping. An attempt to understand this effect is made in terms of a quantitative model which allows an estimation of values for silicon self-diffusivity and which is in accord with the experimental observations