Heat-flow calculation of pulsed excimer ultraviolet laser’s melting of amorphous and crystalline silicon surfaces

We have used a heat-flow model to calculate the melting threshold energy of crystalline (c-Si) and amorphous (a-Si) silicon that is due to ultraviolet pulsed-laser irradiation. Results agree well with the measured values. By simulating the observed laser energy dependence of the melt depths of single-crystal silicon, the reflectivity of liquid silicon Rl at 249 nm at 1683 K was estimated to be 0.68. However, it was found that the available experimental data for a-Si would lead to a value of Rl of 0.57 at 249 nm, assuming the melting point of a-Si to be 1420 K and the latent heat for fusion to be 1320 J g−1.