Normally-off β-Ga<sub>2</sub>O<sub>3</sub> Power Heterojunction Field-Effect-Transistor Realized by p-NiO and Recessed-Gate
Xuanze Zhou, Qi Liu, Weibing Hao, Guangwei Xu, Shibing Long
Abstract
In this work, we designed and fabricated a p-NiO gate heterojunction field effect transistor (HJFET) with gate-recessed architecture based on β-Ga <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> . 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 <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> channel can be fully depleted at zero bias. As a result, high performance β-Ga <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> HJFET with normally-off operation was realized, exhibiting a positive threshold voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> ) of 0.9 V (defined at I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</inf> of 0.1 mA/mm), a negligible V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> hysteresis, a low sub-threshold swing (SS) of 73 mV/dec, a maximum transconductance (g <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> ) of 14.8 mS/mm and a low specific ON-resistance (R <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</inf> ) of 151.5 Ω•mm. Besides, an off-state breakdown voltage of 980 V was obtained at a gate-to-drain distance (L <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">gd</inf> ) of 6 μm. Accordingly, the p-NiO and recessed-gate is an alternative choice for realizing high performance normally-off β-Ga <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> O <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> FETs.