Semiconductor device including switching device having four-terminal structure

Abstract

A semiconductor device has a lateral switching device that includes a channel forming layer, a gate structure portion, a source electrode, a drain electrode, a third semiconductor layer, a fourth semiconductor layer, and a junction gate electrode. The gate structure portion has a gate insulating film provided in a recess portion of the channel forming layer and a MOS gate electrode functioning as a gate electrode of a MOS structure provided on the gate insulating film. The source electrode and the junction gate electrode are coupled through an electrode layer provided on an interlayer insulating film covering the MOS gate electrode. An end of the third semiconductor layer facing the drain electrode protrudes toward the drain electrode from an end of the fourth semiconductor layer facing the drain electrode by a distance in a range of 1 μm to 5 μm both inclusive.