| 摘要 |
PROBLEM TO BE SOLVED: To provide a high voltage resistant horizontal MOSFET which can improve an ON voltage resistance at a curvature of an edge in a semiconductor device having a straight cell. SOLUTION: In the horizontal MOSFET; an n-type well area 4 and a p-type offset area 2 are formed on a surface layer of an n-type semiconductor substrate 1 separated each other, a p-type source area 5 and an n-type contact area 6 are formed on the surface layer of the n-type well area 4, and a p-type drain area 3 is formed on the surface layer of the p-type offset area 2. Further, a first gate oxide film 7 is formed on the n-type well area 4 and the n-type semiconductor substrate 1, an LOCOS 8 is formed on the p-type offset area 2 adjacent to the first gate oxide film 7, and a gate electrode 10 is formed on the first gate oxide film 7. The curvature up to the n-type well area 4 is covered with a second gate oxide film (LOCOS 8) thicker than the first oxide film 7. The electric field concentration on the surface of the n-type well area 5 can be eased, and the ON voltage resistance can be improved. COPYRIGHT: (C)2008,JPO&INPIT
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