SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SAME

摘要

Provided is a semiconductor device having a high withstand voltage and high reliability even with a thin gate electrode. The semiconductor device is provided with a structure wherein a polycrystalline semiconductor layer, a gate insulating film and the gate electrode are successively stacked on an insulating substrate. In the stacked structure of the semiconductor device, the polycrystalline semiconductor layer has a surface roughness of 9nm or less, and the gate insulating film has a silicon oxide film on the polycrystalline semiconductor layer side and a film composed of a material having a dielectric constant higher than that of the silicon oxide on the gate electrode side.