Simulation of a High-Voltage β-Ga2O3 Fin-gate MISFET with Dynamic Channel Barrier for High BFOM and Low Reverse-Conducting Loss

A high-voltage Fin-gate β-Ga2O3 MISFET with Dynamic-Channel-Barrier (DCB-MISFET) is proposed and verified by experimentally calibrated TCAD simulation. The DCB is achieved by a p-NiO trench adjacent to the gate. In forward conduction, the effective channel barrier height is increased and high threshold voltage is obtained owing to p-NiO/Ga2O3 interface. In reverse conduction, the intrinsic low channel barrier enables a low reverse on-state voltage drop VR_on (~2.1 V, 47.5% lower than conventional FG-MISFET). Besides, the p-NiO shields the bottom of gate dielectric, improving the breakdown voltage (BV) and reliability. The DCB-MISFET with single gate (Case I) and double gate (Case II) has BV of 2322 V and 1835 V with specific on-resistance (Ron,sp) being 2.05 mΩ·cm2 and 1.80 mΩ·cm2. Compared to FG-MISFET (BV = 1310 V, Ron,sp = 1.55 mΩ·cm2), Baliga’s FOM improves by 137% and 68% for Case I and Case II. Gate charges(QG) 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 lower CGS and CGD.