Pulsed laser melting of amorphous silicon layers

Abstract

We have investigated microstructural changes in self-implanted and arsenic-ion-implanted amorphous silicon layers as a function of energy density after pulsed ruby laser irradiation, using cross-section transmission electron microscopy and Rutherford backscattering. In specimens irradiated with energy densities less than that required to cause complete annealing, we have identified two distinct regions; the first one consisting of fine polycrystals and the second one consisting of large polycrystals. The changes in thickness of these two regions as a function of pulse energy density are described. Concomitant changes in arsenic concentration profiles are consistent with diffusion in liquid silicon. From the profile broadening in the large polycrystalline region, the crystal growth velocity was estimated to be 4–6 ms−1.