Ultra-bandgap semiconductor material, β-gallium oxide (β-Ga₂O₃), has great potential for fabricating the next generation of high-temperature, high-voltage power devices due to its superior material properties and cost competitiveness. In addition, β-Ga₂O₃ has the advantages of high-quality, large-size, low-cost, and controllable doping, which can be realized by the melt method. It has a wide bandgap of 4.7–4.9 eV, a large breakdown field strength of 8 MV/cm, and a Baliga figure of merit (BFOM) as high as 3000, which is approximately 10 and 4 times that of SiC and GaN, respectively. These properties enable β-Ga₂O₃ to be strongly competitive in power diodes and metal-oxide-semiconductor field-effect transistor (MOSFET) applications. Most of the current research is focused on electrical characteristics of those devices, including breakdown voltage (V_BR), specific on-resistance (R_ON,SP), power figure of merit (PFOM), etc. Considering the rapid development of β-Ga₂O₃ diode technology, this review mainly introduces the research progress of different structures of β-Ga₂O₃ power diodes, including vertical and lateral structures with various advanced techniques. A detailed analysis of Ga₂O₃-based high-voltage power diodes is presented. This review will help our theoretical understanding of β-Ga₂O₃ power diodes as well as the development trends of β-Ga₂O₃ power application schemes.

In this paper, a novel β -Ga ₂ O ₃ vertical fin field-effect transistor (FinFET) with a double drift layer (DDL) is proposed. The DDL structure is realized by incorporating a highly doped (HD) region into the low-doped drift layer of the proposed vertical FinFET device. The effects of the HD region width ( w ), doping concentration ( N _HD ) and height ( t ) on the device’s electrical characteristics were investigated and optimized systematically. The simulated results reveal that the DDL structure can significantly alter the specific on-resistance ( R _ON,SP ) while maintaining the approximate breakdown voltage ( V _BR ), thereby improving the value of the power figure of merit (PFOM). In addition, by optimizing the values of w, N _HD and t , high PFOMs of 614 MW cm ⁻² and 805.8 MW cm ⁻² were achieved at t = 4.22 μ m and 9.22 μ m, respectively. Compared with single drift layer devices with the same doping concentration, the calculated PFOM has increased by 33.47% and 12.69% with the corresponding V _BR decreased by only 10% and 3%, respectively. The existing results demonstrate that excellent device characteristics can be achieved with a DDL structure for β -Ga ₂ O ₃ vertical FinFETs. This proposed DDL structure can provide a valuable foundation for subsequent research on improving β -Ga ₂ O ₃ vertical device performance.

This review introduced selected experimental and numerical studies of β-Ga₂O₃ power field-effect transistors, with emphasis on lateral and vertical metal–oxide–semiconductor field-effect transistors (MOSFETs), heterojunction devices, and superjunction-related concepts. Device classes are distinguished by a gate control, current-flow direction, and charge-compensation mechanism. Diode and capacitor studies are also included because they form transistor contacts and gate stacks. Four benchmark tables organize 30 device configurations, separating fabricated devices from numerical concepts and retaining source-specific resistance normalization, operating conditions, and evidence limitations. The synthesis links reported performance gains to their conduction, interface, and thermal costs. Intrinsic material estimates, measured device capabilities, and projected circuit benefits are assessed separately. Incomplete normalization and parameter pairing constrain cross-study comparisons, while dynamic resistance, gate-stack lifetime, electrothermal failure, and reproducibility remain architecture-dependent validation needs. Static breakdown voltage alone does not establish switching performance, manufacturing yield, or commercialization readiness. This review will help our theoretical understanding of β-Ga₂O₃ power MOSFETs as well as the development trends of β-Ga₂O₃ power application schemes.