Normally OFF GaN-on-Si MIS-HEMTs Fabricated With LPCVD-SiNx Passivation and High-Temperature Gate Recess

Low-current-collapse normally OFF GaN-on-Si MIS high-electron-mobility transistors (MIS-HEMTs) are fabricated with low-pressure chemical-vapor-deposited SiNx(LPCVD-SiNx) passivation and high-temperature low-damage gate-recess technique. The high-thermal-stability LPCVD-SiNxenables a passivation-prior-to-ohmic process strategy and effectively suppresses deep states at the passivation/HEMT interface. The fabricated MIS-HEMTs feature a high VTHof +0.85 V at the drain current of 1 μA/mm and a remarkable ON/OFF current ratio of 1010while reduced dynamic ON-resistance as compared to plasma-enhanced chemical-vapor-deposited SiO2passivation. High field-effect channel mobility of 180 cm2/V·s is achieved, leading to a high maximum drain current density of 663 mA/mm.