| 摘要 |
PURPOSE:To improve and stabilize a withstanding voltage between a first and a second polycrystalline silicon films by a method wherein, after a first silicon oxide film and a gate electrode have been etched, a second silicon oxide film is deposited while a side wall is formed on the side wall of the gate electrode and the first silicon oxide film. CONSTITUTION:After a gate oxide film 101 has been formed on a substrate 100, a first polycrystalline silicon film 102 is deposited. After phosphorus has been diffused, a first silicon oxide film 103 is deposited. Then, the first silicon oxide film 103 and the first polycrystalline silicon film 102 are dry-etched by using a resist pattern. After, that a second silicon oxide film is deposited; the whole surface is etched again by a dry etching method; side walls 104 are formed on the side walls of the first polycrystalline film 102 and the first oxide film 103. Then, after a third silicon oxide film 105 has been deposited, an opening for a source or a drain or for both is made, and the silicon substrate 100 is exposed by etching.
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