X-band power performance of N-face GaN MIS-HEMTs

A report is presented on the X-band power performance of N-face GaN-based metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs). The use of an AlN-based back-barrier enabled low sheet resistance, eliminated alloy disorder scattering to the 2-D electron gas (2DEG), and provided carrier confinement under high electric fields for device scaling. At 10 GHz, a peak power-added efficiency of 56 with a continuous-wave output power density (P_out) of 5.7 W/mm were measured in devices with 0.7 m gate length and 28 V drain bias. A maximum drain efficiency of 70 and saturated output power density of 6 W/mm were achieved. These results are the first demonstration of dispersion-free large-signal operation in N-face devices beyond the C-band.