Enhancement-mode Al2O3/InAlGaN/GaN MOS-HEMTs with a record drain current density of 1.7 A/mm and a threshold voltage of +1.5 V

The paper reports high performance enhancement-mode MOS-HEMT based on quaternary InAlGaN barrier. A self-aligned gate technology is used for gate recessing, dielectric deposition and gate electrode formation processes, where improved digital recessing process as well as O2 plasma-assisted Al2O3 gate dielectric is developed. Fabricated E-mode MOS-HEMT delivers a record output current density of 1.7A/mm with a threshold voltage (VTH) of 1.5 V, and a small on-resistance (Ron) of 2.0 Q-mm. Excellent VTH hysteresis and greatly improved gate leakage characteristics are also demonstrated.