ON THE MODELING OF SILICON-WAFER SLOPING WITH PHOSPHORUS FROM A SOLIDPLANAR DIFFUSION SOURCE

A model for the phosphorus oxide concentration profile in the gas phas e between silicon wafer and solid planar diffusion source has been dev eloped for the case of external-diffusion control of PxOy emission fro m the source. On the assumption that the uniformity of the doping char acteristics across the silicon wafer radius coincides with the concent ration uniformity, experimental results available from the literature for the sheet resistance distribution have been interpreted. The model predicts the system behaviour at high temperatures and atmospheric pr essure and the uniformity of the sheet resistance in the central part of the silicon wafer much better than that developed for the internal- diffusion control of PxOy emission. The subjects of further experiment al research needed for a more profound understanding of the doping pro cess have been defined.