A method to form the gate oxide and recrystallize the polycrystalline silicon (poly-Si) active layer simultaneously is proposed. During the irradiation of excimer laser, the poly-Si film is recrystallized while the oxygen ion impurities injected into the amorphous silicon(a-Si) film are activated by laser energy and react with silicon atoms to formSiO2.Our experimental results show that a high quality oxide and a poly-Si film with fine grain have been fabricated successfully by the proposed method. High quality interface between oxide and poly-Si films has also been obtained. ©1997 American Institute of Physics.