High electron mobility transistor with doped semiconductor region in gate structure

Abstract

A transistor device includes a gate fin that is a segment of a semiconductor body disposed between a pair of gate trenches formed in an upper surface of the semiconductor body, a plurality of two-dimensional charge carrier gas channels disposed at different vertical depths within the gate fin, source and drain contacts arranged on either side of the gate fin in a current flow direction of the gate fin, the source and drain contacts each being electrically connected to each one of the two-dimensional charge carrier gas channels, and a gate structure that is configured to control a conductive connection between the source and drain contacts. The gate structure includes a region of doped type III-nitride semiconductor material that covers the gate fin and extends into the gate trenches, and a conductive gate electrode formed over the region of doped type III-nitride semiconductor material.