| 摘要 |
PROBLEM TO BE SOLVED: To make compatible a high turn-off gain and low off-resistance by a method wherein there is formed an auxiliary region where a first conductive semiconductor layer and a second conductive semiconductor layer having a carrier integral amount the repetitive direction of a predetermined value or less are alternately adjacent to each other. SOLUTION: An auxiliary region 16 where a P-type layer and an N-type layer are alternately disposed is formed in a region sandwiched between P+-type gate layers 4, and a P-type layer of the auxiliary region 16 is connected to the P+-type gate layers 4. Here, a concentration and width of the respective layers are established so that carrier integral amounts calculated from concentration X width of the P-type layer and N-type layer of this auxiliary region 16 substantially agree with each other at schematically 5×1012 cm2 or less. With this structure, since the concentration of the N-type layer of the auxiliary region 16 can be established to be higher than that of an N--type base layer 2, it is possible to decrease resistance components of the region pinched between the P+-type gate layers 4. Accordingly, it is possible to obtain a high turn-off gain, and also to realize a sufficiently low on-resistance. |
