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 β-Ga
2
O
3
. 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 β-Ga
2
O
3
channel can be fully depleted at zero bias. As a result, high performance β-Ga
2
O
3
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 V
th
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 Ω•mm. Besides, an off-state breakdown voltage of 980 V was obtained at a gate-to-drain distance (L
gd
) of 6 μm. Accordingly, the p-NiO and recessed-gate is an alternative choice for realizing high performance normally-off β-Ga
2
O
3
FETs.