Insulated gate power semiconductor devices

摘要

A trench-gate semiconductor device ( 100 ) has a trench network (STR 1 ), ITR 1 ) surrounding a plurality of closed transistor cells (TCS). The trench network comprises segment trench regions (STR 1 ) adjacent sides of the transistor cells (TCS) and intersection trench regions (ITR 1 ) adjacent corners of the transistor cells. As shown in FIG. 16 which is a section view along the line II-II of FIG. 11, the intersection trench regions (ITR 1 ) each include insulating material ( 21 D) which extends from the bottom of the intersection trench region with a thickness which is greater than the thickness of the insulating material ( 21 B 1 ) at the bottom of the segment trench regions (STR 1 ). The greater thickness of the insulating material ( 21 D) extending from the bottom of the intersection trench regions (ITR 1 ) is effective to increase the drain-source reverse breakdown voltage of the device ( 100 ). The insulating material ( 21 D) which extends from the bottom of each intersection trench region (ITR 1 ) may extend upwards to thicken the insulating material at the corners of the cells (TCS) over at least part of the vertical extent of the channel-accommodating body region ( 23 ) so as to increase the threshold voltage of the device.