| 摘要 |
PROBLEM TO BE SOLVED: To introduce impurity ions into a high-concentration impurity area as well as into a polysilicon gate without causing fault due to the displacement of a mask, when forming a MOS transistor structure wherein a drain area is formed of a low-concentration impurity area and a high-concentration impurity area. SOLUTION: A side wall oxide film 21 is formed in an n-channel transistor area, and it is adjacent to the side of an n-type polysilicon gate 19 on an n-type drain low-concentration impurity area 13, and its thickness is larger than that of a gate oxide film 17. It does not cover the upper surface of the n-type polysilicon gate 19, its upper surface is flat, and it is made of a silicon oxide film. The side wall oxide film 21 is also formed in a p-channel transistor area, it is adjacent to the side of a p-type polysilicon gate 33 on a p-type drain low-concentration impurity area 29, and its thickness is larger than that of the gate oxide film 17. It does not cover the upper surface of the p-type polysilicon gate 33, and its upper surface is flat and it is made of a silicon oxide film. COPYRIGHT: (C)2008,JPO&INPIT
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