| abstract |
PROBLEM TO BE SOLVED: To flatten unevenness of a surface of a polycrystalline silicon thin film by a simple process, thereby to make a film thickness of a gate insulating film and the like provided thereon uniform over the entire surface and to withstand a withstand voltage of the insulating film. The purpose is to improve the performance. SOLUTION: Utilizing that a convex portion of a polycrystalline silicon surface oxidizes faster than a concave portion, the surface of the polycrystalline silicon is forcibly oxidized, and the oxidized portion of the surface is etched to reduce unevenness, It can be planarized. |