Atomistic modeling of amorphization and recrystallization in silicon

We propose an atomistic model to describe the evolution of the damage generated by irradiation in Si, going from isolated point defects to the formation of continuous amorphous layers. The elementary units used to reproduce the defective zones are Si interstitials, vacancies and the bond defect, which is a local distortion of the Si lattice without any excess or deficit of atoms. More complex defect structures can be formed as these elementary units cluster. The amorphous pockets are treated as agglomerates of bond defects characterized by their local coordination. The model is able to reproduce the abrupt regime in the crystal-amorphous transition in Si and the epitaxial recrystallization upon annealing as observed in the experiments. The model extends the atomistic kinetic Monte Carlo simulation technique to high implant doses, adequately describing the amorphization and regrowth in Si.