The effects of dopants and excess silicon on the oxidation of TaSi2/Polycrystalline silicon structures.

The oxidation rates of TaSi2/polysilicon structures have been studied as a function of dopants in the polysilicon and as a function of excess silicon in the silicide. Our results indicate that the oxidation rate is significantly affected: B in the polysilicon enhances the oxidation while As retards the rate. P doping by ion implantation showed little effect, but doping by PBr3 diffusion retarded the oxidation. Excess silicon in the silicide retards the oxidation. These phenomena can be explained by a mechanism in which the kinetics is controlled by the silicon out-diffusion through the silicide.