High-threshold-voltage normally-off high-electron-mobility transistor and preparation method therefor

Abstract

A high-threshold-voltage normally-off high-electron-mobility transistor (HEMT) includes a nucleation layer and an epitaxial layer are grown sequentially on a substrate; a barrier layer, a source, and a drain above the epitaxial layer; the barrier layer and the epitaxial layer form a heterojunction structure, and the contact interface therebetween is induced by polarization charges to generate two-dimensional electron gas. The HEMT includes a passivation layer above the barrier layer; a gate cap layer above the gate region barrier layer; the upper part of the gate cap layer is subjected to surface plasma oxidation to form an oxide dielectric layer, or a single-layer or multiple gate dielectric insertion layer is directly deposited thereon. The HEMT includes a gate is located above the gate dielectric insertion layer; the gate is in contact with the passivation layer; and a field plate extends from the gate to the drain on the passivation layer.