Gate Recessed Quasi-Normally OFF Al₂O₃/AlGaN/GaN MIS-HEMT With Low Threshold Voltage Hysteresis Using PEALD AlN Interfacial Passivation Layer

In this letter, a gate recessed normally OFF AlGaN/GaN MIS-HEMT with low threshold voltage hysteresis using Al 2 O 3 /AlN stack gate insulator is presented. The trapping effect of Al 2 O 3 /GaN interface was effectively reduced with the insertion of 2-nm AlN thin interfacial passivation layer grown by plasma enhanced atomic layer deposition. The device exhibits a threshold voltage of +1.5 V, with current density of 420 mA/mm, an OFF-state breakdown voltage of 600 V, and high ON/OFF drain current ratio of ~10 9 .