| 摘要 |
PURPOSE:To decrease leaking current and the like, by adding impurities of P, As, B and the like into the lowermost end of a polycrystalline silicon film at a concentration higher than an upper surface part, patterning the polysilicon, thermally oxidizing the upper surface part and the lower wall part of the silicon pattern, forming an insulating film, and forming an oxide film on the polycrystalline silicon uniformly. CONSTITUTION:A polycrystalline silicon film 3 is deposited on an insulating film, which is provided on a silicon substrate 1. Impurities of P, As or B are added so that the concentration of the lower end of the silicon film becomes 1X10<21>cm<-3> and the concentration of the upper end part becomes 1X10<20>cm<-3>. Thus a high concentration layer 4 is formed. Then, photoresist 5 is applied on the silicon film 3. A pattern is formed on the resist 5 by exposure and development. With the resist as a mask, reactive ion etching is performed, and a pattern 3a of a polycrystalline silicon film is formed. Then, the upper surface part and the side wall part of the pattern 3a, from which the resist 5 is released, undergo thermal oxidation by a lamp heating method, and an oxide film 6 is formed. Thus, a high quality semiconductor device is manufactured. |
