| 摘要 |
PURPOSE:To contrive the improvement of the element characteristics by preventing a narrow channel effect by selectively diffusing impurities into the semiconductor substrate using a slope of the resit layer covering the nitride and oxide films on the substrate as a mask. CONSTITUTION:On a P type substrate 6, an oxide film 7' is formed, on which a nitride film 8 and further a photoresist layer 9 are formed. Next, after forming the layer 9, the film 8 is etched into the predetermined pattern using the remaining layer 9 as a mask. Then, a resist layer 10 is spread over the whole surface of the substrate 6 including the film 8. Then the boron ions are implanted through the layer 10 to form the part 4' to become an isolation diffusion layer. Consequently, an inclined part of an edge 12 on the layer 10 functions as a mask for ion implantation so that a boundary of the ion implantation exists apart from and toward the outside of the undr-part of the film 8 by a pattern size Y as compared with a mask pattern by self-aligning. As a result, interference to the channel region by the region 4' can be eliminated.
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