ABSTRACT: Crystallization of amorphous Si (a-Si) thin film has received extensive interest for their attractive applications into Si thin film transistors and Si based solar cells. Among various crystallization techniques, Solid phase crystallization (SPC) and Excimer laser crystallization (ELC) were investigated. Firstly, Solid phase crystallization (SPC) of amorphous silicon thin films deposited by the DC magnetron sputtering system with a modification in nucleation step was investigated at low temperature. The thin film consists of polycrystalline nanoparticles embedded in an amorphous matrix which can act as nuclei during crystallization, resulting in a lower thermal energy for the nucleation. The lowering energy barrier for nucleation would shorten the transition time from amorphous into polycrystalline silicon resulting from the reduction of incubation time and also lower the processing temperature spontaneously. In addition, a comprehensive study of the growth mechanism of the sputtered amorphous silicon thin films is presented during annealing. Samples were prepared with various substrate temperatures and RF power in order to optimize the crystallization of a-Si after the deposition. Also, the effects of annealing condition were examined. Low pressure N2 ambient during SPC promoted crystallization of a-Si thin films and the crystallinity. The low pressure annealing had a large impact on the crystallinity and growth behavior of subsequent films.