Bidirectional trench fet with gate-based resurf

Abstract

A device includes a semiconductor substrate having a surface, a trench in the semiconductor substrate extending vertically from the surface, a body region laterally adjacent the trench, spaced from the surface, having a first conductivity type, and in which a channel is formed during operation, a drift region between the body region and the surface, and having a second conductivity type, a gate structure disposed in the trench alongside the body region, recessed from the surface, and configured to receive a control voltage is applied to control formation of the channel, and a gate dielectric layer disposed along a sidewall of the trench between the gate structure and the body region. The gate structure and the gate dielectric layer have a substantial vertical overlap with the drift region such that electric field magnitudes in the drift region are reduced through application of the control voltage.