| 主权项 |
1. A semiconductor device comprising:
a source electrode; a gate electrode; a drain electrode; a first region of a first conductivity type formed in a range exposed at an upper surface of a semiconductor substrate, and making contact with the source electrode; a second region of a second conductivity type formed in a range exposed at the upper surface, adjacent to the first region, and facing the gate electrode through a gate insulating layer; a third region of the first conductivity type formed in a range exposed at the upper surface, and making contact with the drain electrode; and a fourth region of the first conductivity type formed in a range exposed at the upper surface, formed between the second region and the third region, and comprising:
a first drift region formed in a range exposed at the upper surface between the second region and the third region;a second drift region having a first conductivity type impurity concentration higher than that of the first drift region, and adjacent to the first drift region positioned between the second region and the third region; anda low concentration drift region having a first conductivity type impurity concentration lower than that of the first drift region, and formed between the second region and the second drift region, wherein both of the first drift region and the second drift region are adjacent to the third region, and the first drift region is projected to a second region side than the second drift region. |
