16.8 A/600 V AlGaN/GaN MIS-HEMTs employing LPCVD-Si3N4 as gate insulator

An AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor (MIS-HEMT) on Si substrate was obtained with 18 nm silicon nitride (Si₃N₄) grown by low-pressure chemical vapour deposition (LPCVD) as the gate insulator. The D-mode MIS-HEMT shows a high I_dss of 16.8 A at V_g = 3 V, a high breakdown voltage (BV) of 600 V and a low-specific on-resistance of 2.3 mΩ·cm². The power device figure of merit (FOM = BV²/R_on,sp) is calculated as 157 MW·cm^-2. The good insulation effects of LPCVD-Si₃N₄ were also demonstrated by the low gate leakage current of 154 nA at V_ds = 600 V and V_gs = -14 V. Furthermore, an E-mode device was realised by a low-voltage silicon metal-oxide-semiconductor field-effect transistor in series; the V_th was determined to be 2.6 V. The high I_dss, low-specific on-resistance, high BV and positive V_th show the potential and advantages of GaN MIS-HEMTs for power switching applications.