| 摘要 |
PURPOSE:To structure a highly reliable element by preventing the breakdown strength of a gate insulating film from being deteriorated when the field oxide film is etched. CONSTITUTION:On the surface of a silicon substrate 2, a gate oxide film 22 and a field oxide film which is not shown in the figure are formed. On the gate oxide film 22 and field oxide film, a conductivity poly silicon is deposited, which is patterned to form gate electrodes 28 and 29. After a nitride film is deposited on the gate electrodes 28 and 29, side walls 32 and 33 are formed on the sidewall parts of the gate electrodes 28 and 29 by an isotropic etching. Then, with the gate electrodes 28 and 29, and side walls 32 and 33 as masks or a part of masks, the field oxide film between the gate electrodes 28 and 29 is etched to enable the silicon substrate 21 to be exposed. The structure is thus arranged to form an impurity diffusion layer 30 by introducing an impurity such as As<+> into the silicon substrate 21.
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