Process simulation for laser recrystallization

Simulation of energy absorbtion of laser beam. Reflection, transmission and absorption by a multilayer optical structure was calculated using approximation of Maxwell eq. for homogenous layers. Simulation of heat transport. The solution of 3-dimensional heat transport problem is based on FD method. The non-linearity of H-T dependence at the melting point represents the main numeric problem. Modeling of formation of grain boundary defects. Based on modeling of the facetted growth of Si films we used Monte-Carlo simulations to describe the grain boundary formation at any given temperature distribution. The simulations are agreeable with experimental results, both for beam shaping technique, as well for application of so called integrated absorbers. Based on the simulation results we introduced a new method called micro absorber to suppress the formation of grain boundaries during laser recrystallization. Areas free of grain boundaries of up to 100 mym x 50 mym are obtained in our first e xperiments.