| 摘要 |
A semiconductor device including an IGFET (insulated gate field effect transistor) ( 30 ) is disclosed. IGFET ( 30 ) may include a source/drain area ( 15 ) having an impurity concentration distribution that may be formed shallower at a higher concentration than the impurity concentration distribution in another source/drain area ( 7 ). A gate oxide film may include a first gate oxide film ( 5 ) adjacent to source/drain area ( 7 ) and a second gate oxide film ( 12 ) adjacent to source drain area ( 15 ). Second gate oxide film ( 12 ) may be thinner than first gate oxide film ( 5 ). An impurity concentration distribution of a second channel impurity area ( 11 ) under second gate oxide film ( 12 ) may be at a higher concentration than an impurity concentration distribution of a first channel impurity area ( 9 ) under first gate oxide film ( 5 ). In this way, an electric field at a PN junction of source/drain area ( 7 ) may be reduced.
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