The diffusion of a buried antimony layer is only 20% of its normal diffusion in an inert ambient after a phosphorus implant is performed at the surface of a silicon wafer.
The phosphorus diffusion coefficient is itself enhanced by a factor of 4(400%).
a. Suggest a qualitative reason for this observation.
b. Assuming that the phosphorus diffuses completely by an interstitial mechanism, calculate how much of the antimony diffusion is mediated by interstitials and how much by vacancies.