Demonstration of β-Ga₂O₃ Superjunction-Equivalent MOSFETs

In this work, we, for the first time, demonstrate $\beta $ -Ga ₂ O ₃ lateral superjunction (SJ) -equivalent metal–oxide–semiconductor field-effect transistors (MOSFETs). The electric field engineering is implemented by the alternatively arranged p-NiO/n-Ga ₂ O ₃ lateral hetero-SJ, which is constructed through the selective epitaxial filling of p-NiO pillars into the trenched drift region of $\beta $ -Ga ₂ O ₃ . The static electrical characteristics indicate that $\beta $ -Ga ₂ O ₃ SJ-equivalent MOSFETs outperform the control transistor without the SJ structure. In particular, the Ga ₂ O ₃ SJ-equivalent MOSFET with a p-NiO pillar width of 2 $\mu \text{m}$ demonstrates a breakdown voltage ( ${V}_{\text {br}}$ ) of 1362 V and a power figure-of-merit (PFOM) of 39 MW/cm ² , which are 2.42 and 4.86 times higher, respectively, than those of the control device. The large divergence of the experimental performance from the theoretical predictions is attributed to the charge imbalance caused by the substrate-assisted depletion effect and superimposed interfacial charges. With the proper interface engineering and controlled doping, it is expected that utilizing p-NiO/n-Ga ₂ O ₃ hetero-SJ is a promising technological strategy to allow a favorable trade-off between ${V}_{\text {br}}$ and ON-state loss of Ga ₂ O ₃ transistors for the high-efficiency power conversion.