| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology for reducing the continuity resistance of a power MOSFET. SOLUTION: Related to a power MOSFET1, when a first gate electrode 41 is applied with a voltage equal to or higher than a threshold, while a voltage is applied between a source region 36 and a main semiconductor layer 12 which is the drain, an inversion layer is formed at the interface between a first gate insulating film 95 formed on the side surface of a trench 22 and a body region 32, and a current flows from the main semiconductor layer 12 to the source region 36 through the inversion layer. A channel width of the MOS transistor 1 depends on the depth of the first gate electrode 41, and the deeper the first gate electrode 41 is the wider channel width becomes, resulting in a lower continuity resistance of the MOS transistor 1. Thus, the continuity resistance is lowered by forming the first gate electrode 41 deeper, without enlarging the occupancy area, so that the continuity resistance can be made lower than before.
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