| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device and a manufacturing method thereof that improve gate reliability while suppressing the increase of an on-state resistance. SOLUTION: By using a silicon substrate with a surface of a (100) plane, a trench 5 is formed along the (100) plane of a crystalline orientation in a cell region. On the other hand, a trench 14 is formed along a (110) plane of the crystalline orientation in a gate withdrawal-wiring region. Then, the surfaces of the trenches 5, 14 thermally oxidized, for example, at a low temperature in 850-1,000°C so that the plane orientation dependence of an oxidation speed appears. The gate oxide film of the gate withdrawal-wiring region is made a thicker structure than that of the cell region. Consequently, the film thickness of the gate oxide film is made thicker while maintaining the gate oxide film in the cell region at a film thickness similar to that of the conventional structure. COPYRIGHT: (C)2004,JPO
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