| 摘要 |
PURPOSE:To increase breakdown voltage and decrease ON-resistance, by making the specific resistance of the surface layer of a peripheral part larger than that of a drain composed of a semiconductor layer. CONSTITUTION:An n-type impurity layer 4 and an n-type low concentration impurity layer 3 are arranged on the surface of a drain 2 composed of an n-type low concentration semiconductor layer on an n<+> type high concentration silicon substrate 1 having a drain electrode 12 on the rear. On the surface of an impurity layer 4, an active region is arranged, which comprises the following; an n<+> type high concentration source 7 on the surface, a base 6 between the sources 7, and a gate 8 formed on the impurity layer 4 via a gate insulating film. Thereby, the extension of a depletion layer in a pheripheral part is increased and the breakdown is improved. Further, by making the specific resistance of the surface layer of the active region smaller than that of the drain, the drain resistance is reduced and a low ON-resistance is obtained. |
