Semiconductor device and producing method thereof

Forming a semiconductor layer of working in such a manner, such that the amorphous silicon layer is formed to have a wide area and a narrow area, the narrow area and the wide-area location with respect to asymmetrically connected to the wide region, and as a heat a polysilicon layer remains lower layer via a silicon oxide layer is wrapped from the side of the narrow area state, the continuous wave laser beam scanning the wide region to the narrow region, so that the amorphous silicon layer is crystallized no.