Patent ID: 7586151
Filing Date: 2009-09-08
Classification: H01L

Abstract:
1. An insulated gate semiconductor device comprising: a body region which is on the upper side of a semiconductor substrate and is a semiconductor of a first conductivity type; a drift region which is in contact with the bottom of the body region and is a semiconductor of a second conductivity type; a first trench group which are formed in a striped shape when viewed from above, pass through the body region, and contain a gate electrode; a second trench having portions formed in an arc shape when viewed from above; first floating regions which are surrounded by the drift region, surround the bottom of at least one trench of the first trench group, and are a semiconductor of the first conductivity type; and a second floating region which is surrounded by the drift region, surrounds the bottom of the second trench, is equal to the first floating regions in the thickness-wise position in the substrate and is a semiconductor of the first conductivity type, the second trench being a terminal trench surrounding the first trench group when viewed from above; electric field strength peak at two places in the semiconductor substrate in a thickness direction: at a first PN junction between the first floating regions and the drift region; and at a second PN junction between the body region and the drift region; and each end of each trench of the first trench group being perpendicular to a side portion of the second trench when viewed from above, shortest distances between the ends of each trench of the first trench group and the respective side of the second trench being equal in length.