Phosphorous-diffusion gettering in the presence of a nonequilibrium concentrationof silicon interstitials: A quantitative model

Abstract

A quantitative model of phosphorous-diffusion gettering in silicon is presented, which combines the effects of segregation and self-interstitial injection on the distribution of dissolved metallic impurities. The model describes metal diffusion both in the bulk and in the highly phosphorous-doped layer and makes it possible to include phosphorous-diffusion models. By analyzing an approximate solution for the quasi-steady-state metal distribution, we show that for impurities like gold and platinum self-interstitial injection enhances the gettering efficiency compared to pure segregation. We apply the results to phosphorous-diffusion gettering of gold and demonstrate that all relevant features of recently measured gold distributions can be interpreted consistently. For 3d metals, which are predominantly dissolved on interstitial sites in intrinsic silicon, the model allows us to include the formation of precipitates resulting from self-interstitial injection as proposed earlier.