High Temperature Operation of E-Mode and D-Mode AlGaN/GaN MIS-HEMTs With Recessed Gates

High temperature operation of enhancement-mode (E-mode) and depletion-mode (D-mode) AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) was demonstrated. By using the circular device structure, off-state current effectively suppressed, record high Ion/Ioff ratio around 108 obtained at 400 ∘C. Atomic layer etching used for formation gate recess structure in E-mode device, good interface made which enabled stable normally-off up to D-mode experienced positive threshold voltage shift during after cooling down room temperature, due strain relaxation. On other hand, very thin AlGaN retained under is nearly unchanged when sample heated cooled down. A direct coupled field-effect transistor logic (DCFL) inverter fabricated based on devices showed