| 摘要 |
PURPOSE:To reduce substrate effect and prevent the variation of threshold voltage by a method wherein oxidation treatment is performed on a member becoming a gate electrode via the pattern of an oxidation resistant mask layer, and accordingly a protection film is formed in the state that a part of the mask layer is left. CONSTITUTION:An n<-> type Si substrate or an Si layer 10 with a p<-> type island region 14 formed on the lower surface of an SiO2 film 12 is prepared. Next, apertures 15 and 17 are provided at the part for forming a MOSFET, and thin gate oxide films 16 and 18 are produced therein. Then, polycrystalline Si's 24 and 26 and further the Si nitride mask layers 28 and 28 are deposited. An n<+> type source region 20 and an n<+> type drain region 22 are formed in the p<-> type island region 14. The side part oxide films 32 or 34 for mask purpose is formed by thermally oxidizing the unmasked both side parts of the layers 24 and 26. Finally, diffusion windows 35 and 37 for a p-channel MOSFET are formed by utilizing the mask layer as a part of a selective mask. |
