Investigation of boron diffusion after pre-amorphization implant with kinetic Monte Carlo approach

In this paper, we report our theoretical investigation on boron diffusion in silicon posterior to PAI (pre-amorphization implant) process in an effort to understand the physical mechanism for forming a shallow and abrupt junction. We performed numerical calculation for examining the characteristics of silicon atoms as a candidate for PAI species. Our KMC (Kinetic Monte Carlo) simulation revealed that PAI process helps to get a shallower junction than the case of PAI-free boron implantation and that Si-PAI process produces more amount of interstitial and vacancy which results in the reduction of so-called boron transient enhanced diffusion (TED). In addition, we made a comparison between Si-PAI and Ge-PAI in terms of the generation dynamics of defects and the effect on the subsequent diffusion of boron. Our KMC study on the interstitial distribution revealed that Si-PAI produces more interstitials than Ge-PAI whilst Ge-PAI help interstitials move further up toward the surface than Si-PAI during the subsequent annealing process.