Provided is a method of fabricating a semiconductor device, the method including: forming an insulating layer on a single crystal substrate; etching the insulating layer in a predetermined pattern to expose the surface of the single crystal substrate; depositing an amorphous material on the insulating layer and the exposed surface of the single crystal substrate; and completely melting the amorphous material on the single crystal substrate and the insulating layer using laser annealing and crystallizing the melted amorphous material. The semiconductor device has a single crystalline silicon gate on the insulating layer.