Atomistic simulations of ion implantation and annealing of Si over a wide range of ion doses and substrate temperatures were considered. A Monte Carlo model was extended so as to include the formation of amorphous regions, and this permitted the simulation of dopant diffusion at high doses. As the ion dose increased, the amorphous regions which were formed by cascades eventually overlapped and a continuous amorphous layer formed. In that case, most of the excess interstitials generated by the implantation were swept to the surface as the amorphous layer re-grew, and did not diffuse in the crystalline region. This process reduced the amount of transient enhanced diffusion during annealing. The model also reproduced dynamic annealing during high-temperature implantation. In this case, the local amorphous regions re-grew as the implantation proceeded without the formation of a continuous amorphous layer. At sufficiently high temperatures, each cascade annealed out independently; interstitials and vacancies could escape from the cascade and thus increased dopant diffusion.

Atomistic Modeling of the Effects of Dose and Implant Temperature on Dopant Diffusion and Amorphization in Si. L.Pelaz, L.A.Marques, G.H.Gilmer, M.Jaraiz, J.Barbolla: Nuclear Instruments and Methods in Physics Research B, 2001, 180[1-4], 12-6