Phosphorus distribution in TaSi2 films by diffusion from a polycrystalline silicon layer

Secondary ion mass spectroscopy was used to measure phosphorus concentration profiles in TaSi2 thin films deposited on P doped polycrystalline Si/SiO2/Si wafers by cosputtering. Fast redistribution of P in TaSi2 takes place by its up-diffusion from the polycrystalline Si layer. Radioactive assay of 32P obtained by neutron activation confirmed the fast-diffusion character of P in TaSi2. From preliminary results the temperature dependence of the diffusion coefficients over the temperature range of 664 °C-913 °C can be expressed by the following relations: Dc=6.44×10−10 exp[−0.61/(kT)] and Da=2.0×10−8 exp[−0.76/(kT)], where Dc and Da represent diffusion in the silicide film near and away from the surface, respectively.