Abstract
Femtosecond laser processing has been providing attractive applications, because it enables us to realize socalled non-thermal laser-matter interaction. It is important to characterize the laser fluence dependence of the interaction process. It is well known that the femtosecond laser irradiation to c-Si (single-crystalline Si) can induce ablation and phase transition from c-Si to a-Si (amorphous Si). We investigated the ultra-fast interaction between laser and c-Si by means of Pump-Probe technique. The results showed three interaction regions: ablation, non-thermal melting, and thermal melting with decreasing of laser fluence. In this paper, we describe the time scale of each process and their laser fluence dependences.
