Damage evolution in implanted silicon by pulsed excimer laser annealing

Abstract

The evolution of the implantation damage during a Pulsed Laser thermal annealing process is investigated by means of an accurate modeling which could stimulates focused experimental analyses. The model is based on the simulation of the detailed kinetic of the defect system in the extremely far-from-equilibrium conditions caused by the laser irradiation in the non-melting, melting and partial melting regimes. It considers defect (interstitials Is and vacancies Vs) clustering and annihilation in presence of fast varying temperature, high thermal gradients and phase transition. Simulations allow a characterization of the residual damage (in terms of total residual defect's density and cluster size distribution) as a function of the process conditions (i.e. laser fluence). The thermal budget supplied to the system in the submelting regime is not sufficient to drive a consistent defect evolution and the total defect's density is slightly reduced with respect the initialization (i.e. the post-implants conditions, where B and P implantations have been considered: Boron 40 keV, 3e14 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> and Phosphorus 350 keV, 1e14 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ). Residual damage after melting processes is considerably reduced when compared to the as implant case. In this cases a relevant portion of the I type defect resides in clusters (small and large) while for the simulated cases clustering does not take place for V type defects.