| 摘要 |
PURPOSE:To form a polycrystalline silicon oxide film excellent in insulating property, by making the height of a insulating film surface where a polycrystalline silicon film is not formed in the upper part of a base insulating film of a worked end-portion of a polycrystalline semiconductor film, lower than the polycrystalline semiconductor film and the insulating film. CONSTITUTION:At the worked end-portion of a polycrystalline silicon film 108, a step-difference shape is arranged on the base insulating film of an insulating film 106, and a structure is made up wherein the insulating film 106 surface of the lower stage of the step-difference shape is made lower than the boundary surface between the polycrystalline silicon film 108 and the insulating film 106. When the lower edge of the worked end-portion of the polycrystalline silicon film 108 is oxidized, and an oxide film 110 is formed on the polycrystalline silicon film 108, the supply of oxidizing agent does not decrease, and the oxide film 110 can be prevented from being thin. Thereby electric field concentration does not occur in a polycrystalline silicon oxide film 111 which is formed in the later process, and excellent insulating property is obtained. |
