| 摘要 |
PROBLEM TO BE SOLVED: To enable the current path between a source and a drain high resistance or breaking it, in condition that gate voltage is not applied. SOLUTION: The second drift region 6 and the first drift region 5 are stacked on an n<+> -drain region 7, and an n<+> -source region 4 is made on the first drift region 5, and a source electrode 8 is made on the n<+> -source region 4. Moreover, a gate insulating film 3 is made on the surface of a gate groove 13, and a gate electrode 2 is made on the gate insulating film 3 so as to stop the gate groove 13. This gate electrode 2 is made of polysilicon doped with p-type impurity atoms, and the impedance of an element is increased by narrowing the current path 35 in such a way that a depletion layer 11 spreads even in condition that gate voltage is not applied, or it is made a normally off type of element by closing the current path 35 by the further micronization of a unit cell. |
