| 摘要 |
PROBLEM TO BE SOLVED: To implant impurities of an optimum density into the periphery of a trench, and to fill a wide trench with an oxide film, in order to manufacture a lateral high breakdown voltage trench MOSFET having an offset drain region around the trench. SOLUTION: In forming the offset drain region 3 around the trench 2, a doped polysilicon film 24 is formed on a trench inner surface and diffused onto a side surface and a bottom surface of a trench groove by performing drive, and then the doped polysilicon film 24 is thermally oxidized. After that, in filling of the trench with the oxide film, the trench 2 is filled with the oxide film 4 by thermal oxidation, or the trench is narrowed by generating the oxide film inside the trench by the thermal oxidation, and then the remaining trench is filled by depositing an oxide. Otherwise, a plurality of the trenches are formed, they are filled with the oxide and a substrate part between the trenches is thermally oxidized and changed into the oxide film. COPYRIGHT: (C)2008,JPO&INPIT
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