Simulation of a high-voltage <i>β</i>-Ga₂O₃ fin-gate MISFET with dynamic channel barrier for high Baliga’s figure of merit and low reverse-conducting loss

Abstract A high-voltage fin-gate β -Ga 2 O 3 Metal Insulation Semiconductor Field Effect Transistor with dynamic channel barrier (DCB-MISFET) is proposed and verified by experimentally calibrated TCAD simulations. The DCB is achieved by a p-NiO trench adjacent to the gate. In forward conduction, the effective channel barrier height is increased and a high threshold voltage is obtained owing to the p-NiO/Ga 2 O 3 interface. In reverse conduction, the intrinsic low channel barrier enables a low reverse on-state voltage drop V R_on (∼2.1 V, 47.5% lower than the conventional fin-gate MISFET (FG-MISFET)). In addition, the p-NiO shields the bottom of the gate dielectric, improving the breakdown voltage (BV) and reliability. The DCB-MISFET with single gate (Case I) and double gate (Case II) has a BV of 2322 V and 1835 V with a specific on-resistance ( R on,sp ) of 2.05 mΩ·cm 2 and 1.80 mΩ·cm 2 . Compared to the FG-MISFET (BV = 1310 V, R on,sp = 1.55 mΩ·cm 2 ), Baliga’s figure of merit improves by 137% and 68% for Case I and Case II, respectively. The gate charges ( Q G ) for Case I and Case II reduce by 59% and 42%. Moreover, the total switching loss is reduced by 64% for Case I and 57% for Case II due to the lower C GS and C GD .