| 摘要 |
PURPOSE: To further improve a reverse voltage, by constituting a 1st conductivity region having conductivity higher than that of a 1st region at a position other than a planar region on the surface of 1st region. CONSTITUTION: A vertical power MOSFET has a semiconductor substrate having a strongly n-doped wafer 1, to which a weakly n-doped 1st region 2 is adjacent. A strongly p-doped planar region 3 is embedded on the surface of 1st region 2. The 1st region 2 has a region 9, which is the same conductivity type as the 1st region 2 but is strongly doped rather than that, on its surface. This region 9 is extended from an edge 16 of semiconductor substrate to the downside of the gate electrode 6. The region 9 is operated for equalizing field strength on the surface of semiconductor substrate. Thus, the peak of field strength is canceled under a channel stopper 7 and a much higher reverse voltage can be provided. |
