ABSTRACTThe Effects of fluorine atoms on laser-induced crystallization have been studied. The defect states of hydrogenated amorphous silicon (a-Si:H) film, which are related to weak hydrogen bonds, were reduced by involving fluorine atoms, before laser annealing. In laser annealing, the crystallinity was also enhanced to 63 %, while that of a-Si:H was 45 % at the energy density of 300 mJ/cm2. It may be considered that the fluorine atoms reduce the hydrogen atoms cause to the degradation of film in laser annealing, and increase the heat capacity which results in promotion of crystallinity in melt-solid phase transition.