POWER SEMICONDUCTOR DEVICES

摘要

A semiconductor device includes a channel-accommodating region (15) extending from a first major surface (10a) of its semiconductor body and separating source and drain regions. The channel-accommodating region defines junctions (15a, 15b) with the source and drain drift regions at the first major surface. First and second gates (33, 35) extend laterally over the first major surface (10a) which are isolated from each other so as to be independently operable. The first gate (33) extends part way across the channel-accommodating region (15) from over said source region junction (15a) towards said drain drift region junction (15b), and the second gate (35) extends over the channel-accommodating region (15) from adjacent to the first gate (33) to over said drain drift region junction (15b) such that the first and second gates are operable to form a conduction channel in the channel­accommodating region between the source and drain regions. In use of the device, a modulating potential is applied to the first gate (33), and a fixed potential is applied to the second gate (35). The device is therefore turned on by application of a sufficient bias potential to the first gate, in combination with a sufficient fixed potential at the second gate. The controlling first gate is spaced from the drain drift region (14) by the associated insulating layer and also a portion of the channel­accommodating region (15). The gate-drain capacitance of the device is therefore negligible, providing a substantial reduction in switching losses.