In this letter, a novel process for recessed-gate AlGaN/GaN high-electron-mobility transistors using an Al2O3/ SiNx dielectric has been developed. The Al2 O3/SiNx dielectric bilayer was used as a recess etch-mask for short-gate-footprint definition. Recessed-gate devices with a gate length of 70 nm have been fabricated on a molecular-beam-epitaxy-grown layer structure using this process. After the removal of the dielectric layers, excellent dc and small-signal results, a high drain-current density of 1.5 A/mm, a unity gain cutoff frequency of 160 GHz, and a maximum frequency of oscillation of 200 GHz were obtained.
- High-electron-mobility transistors (HEMTs)
- Recessed gate
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering