Normally-off β-Ga2O3 Power Heterojunction Field-Effect-Transistor Realized by p-NiO and Recessed-Gate

In this work, we designed and fabricated a p-NiO gate heterojunction field effect transistor (HJFET) with gate-recessed architecture based on beta-Ga2O3. The gate recess process was utilized, and wet chemical etching and annealing process were performed to restored channel mobility. With the depletion effect of p-NiO, the beta-Ga2O3 channel can be fully depleted at zero bias. As a result, high performance beta-Ga2O3 HJFET with normally-off operation was realized, exhibiting a positive threshold voltage (V-th) of 0.9 V (defined at I-d of 0.1 mA/mm), a negligible Vth hysteresis, a low sub-threshold swing (SS) of 73 mV/dec, a maximum transconductance (g(m)) of 14.8 mS/mm and a low specific ON-resistance (R-on) of 151.5 Omega.mm. Besides, an off-state breakdown voltage of 980 V was obtained at a gate-to-drain distance (L-gd) of 6 mu m. Accordingly, the p-NiO and recessed-gate is an alternative choice for realizing high performance normally-off beta-Ga2O3 FETs.