Ultrafast laser-induced crystallization of amorphous silicon films

Ultrashort pulsed laser irradiation is used to crystallize 100-nm amorphous-silicon (a-Si) films. The crystallization process is ob- served by time-resolved pump-and-probe reflection imaging in the range of 0.2 ps to 100 ns. The in-situ images, in conjunction with postpro- cessed scanning electron microscopy (SEM) and atomic force micros- copy (AFM) mapping of the crystallized structure, provide evidence for nonthermal ultra-fast phase transition and subsequent surface-initiated crystallization.