In producing a thin film transistor used for such devices as a large-sized liquid crystal display panel with a high pixel density, a leftover of an insulating film caused by insufficient etching and a loss of a semiconductor layer caused by overetching are prevented, and a reliable electrical contact between the source and drain electrodes and the semiconductor layer is achieved. These are achieved by (a) forming a contact hole region of a silicon film so that the region has a larger thickness, for example, by making the film to have a plurality of layers, and (b) providing a silicide layer between an electrode metal and the semiconductor layer.