Plateau and kink in P profiles diffused into Si: A result of strong bimolecular recombination?

A simplified five-species nonequilibrium kinetic model for phosphorus diffusion in silicon is presented. The resulting system of evolution equations is of a simple reaction-diffusion form with constant diffusivities. Using first-order thermodynamic estimates for reaction rates, the phosphorus profile after a 10 min predeposition shows the expected tail. However, only when the bimolecular generation-recombination rate is significantly increased does a kink-plateau result. This suggests that recombination may be the dominant factor in producing the known nonlinearity.