MANUFACTURE OF SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To obtain a high reliable, high-performance MOS TFT device with a crystalline silicone film used as an active region by after having the outermost portion of the silicon film thin-film-etched, the active region with an insulating film in the upper layer is covered, thus forming it without exposing to air. SOLUTION: When a crystalline silicon film 105 is subjected to reactive etching, the entire surface of the silicon film 105 is turned into a thin film. The etching makes rapid progress especially in the grain boundary 107 where ridges 108 are present, and the ridges are selectively etched and shaved. Here, the exposed surface of the crystalline silicon film 109 is rid of the contaminated region in its surface layer. As a result, the unevenness of the surface is reduced, and the surface is brought into a very clean state. For this reason, a verey clean crystalline silicon film 109-oxide film 110 boundary 111 is obtained, by covering the crystalline silicon film 109 with the oxide film 110 without exposing it to the air.