| 摘要 |
PURPOSE:To prevent a damage layer from being created in an Si substrate, by providing with side walls on both side face of a mask pattern which has been used for forming impurity diffusion regions separated from each other, and by frming a gate electrode using them as a mask. CONSTITUTION:On the surface of a P-type Si substrate 21, a field oxide film 22 is formed. After an oxide film 23 is formed on an island region separated by the film 22, a polycrystalline Si film 24 is formed on the entire face. Next, a resist pattern 25 is formed on the section to form a gate electrode, ad using the pattern 25 as a mask, phosphorus, for example, is ion-implanted to form N<-> impurity regions 261, 262 separated from each other. On the side faces of the pattern 25, side walls 27 serving as a mask for forming the gate electrode are formed. Next, using the pattern 25 and side walls 27 as a mask, etching based on a chemical reaction is done to form the gate electrode 28. The pattern 25 and side walls 27 are then removed. Thereafter, using the electrode 28 as a mask, arsenic, for example, is ion-implanted to form N<+> impurity regions 291, 292.
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