Dopant dynamics and defects evolution in implanted silicon under laser irradiations: A coupled continuum and kinetic Monte Carlo approach

Defect evolution and dopant dynamics in boron implanted silicon under excimer laser irradiation is investigated by means of continuous model and kinetic Monte Carlo (KMC) simulations. Both approaches rule the post-implant kinetics of the defects-dopant system in the extremely far from-the equilibrium conditions caused by the laser irradiation. The thermal problem has been solved within the phase-field methodology. Our model, based on the interaction between defects and the active/inactive impurities, elucidates the dopant activation as well as the observed defect aggregation. Concurrently to the solid-phase problem for the dopant activation, Boron evolution mechanism in silicon melting phase induced by the laser heating have been investigated in details. The analysis suggests an anomalous impurity redistribution in the molten regions induced by the melting laser irradiation related to the mixed (metal+covalent) bonding character of the liquid state. This microscopic mechanism explains the anomalous B segregation whereas accurate comparisons between experimental chemical profiles and simulation results validate the two state diffusion model.