Simultaneous observation of the diffusion of self-atoms and co-implanted boron and carbon in silicon investigated by isotope heterostructures

Diffusion of self-atoms and co-implanted carbon (C) and boron (B) in silicon (Si) has been simultaneously observed using natSi/28Si isotope heterostructures. The supersaturation of Si self-interstitials (I's) is investigated through the 30Si diffusion. The experimental results showed that Si self-diffusion was enhanced, that is, the I is more severely supersaturated, while B diffusion near the kink region was reduced with higher C dose. We also found slower dissolution of immobile BI clusters. C diffusion was not significant, indicating the formation of immobile CI clusters. These results indicate that the reduction of B diffusion is not due to the trapping of I by C, if any, but due to the retardation of BI cluster dissolution by the presence of C to decrease the amount of mobile B. The Si self-diffusion is enhanced by the dissolution of CI clusters to emit I.