Models were developed for the purpose of describing the coupled diffusion of dopants and point defects. Firstly, a general model was found for the occurrence of P diffusion via dopant/defect pairs. This assumed that there was local equilibrium of electronic processes but not of chemical processes. It was concluded that dopant/defect pairing reactions were near to local equilibrium, whereas defect recombination reactions were not. A simplified model, which was based upon the assumption that the pairing reactions were near to equilibrium, was then used to simulate P profiles. By including the diffusion of P via negatively-charged P/vacancy pairs, as well as diffusion via P/interstitial pairs (which predominated in intrinsic materials), it was possible to match experimentally determined P diffusion profiles to surface concentrations which ranged from intrinsic levels to the solid solubility, at 900 or 1000C.

S.T.Dunham: Journal of the Electrochemical Society, 1992, 139[9], 2628-35