Recessed gate normally-OFF Al2O3/InAlN/GaN MOS-HEMT on silicon

In this letter, a gate-recessed Al 2 O 3 /InAlN/GaN normally-OFF metal–oxide–semiconductor high-electron-mobility transistor (MOS-HEMT) on Si is reported. The fabricated MOS-HEMT with a gate length of 1.5 µm features a high drain current density of 840 mA/mm at a gate bias ( V gs ) of +8 V, a low specific ON-resistance of 0.8 mΩ·cm 2 , and a threshold voltage of +1.9 V. The Al 2 O 3 /InAlN/GaN MOS-HEMT also exhibits a low gate leakage current (∼10 −8 mA/mm at V gs = +8 V) and a maximum peak field-effect mobility of 472 cm 2 V −1 s −1 . The OFF-state breakdown voltage of the device ( L gd = 4 µm) is 278 V at V gs = 0 V.