Review on interface engineering of low leakage current and on-resistance for high-efficiency Ga2O3-based power devices

Beta-Gallium oxide (β-Ga 2 O 3 ) has emerged as a very feasible semiconductor material for new explorations, thanks to its advantages of ultra-wide bandgap and diverse material systems. The high breakdown electric field, high working temperature, and excellent Baliga's figure-of-merit (BFOM) of β-Ga 2 O 3 represent an inspiring outlook of power electronic devices. β-Ga 2 O 3 -based materials and devices have been increasingly popular in recent years for power electronics, owing to their ability to generate high-quality bulk substrates at a low cost. In this review article, we describe the recent investigations on the interface engineering of the β-Ga 2 O 3 -based power devices. Meanwhile, different methods for enlightening the performances including breakdown voltage and on-resistance have been summarized. Improved ohmic connections by reducing contact resistance through interfacial engineering and interlayers such as conducting oxides of AZO, ITO, and related materials, as well as the development of selective ion implantation doping. Some solutions to problematic challenges, such as p-type doping difficulty and low thermal conductivity, are also provided and addressed. Transferring devices to another substrate or thinning down the substrate and using heat sinks as well as top-side heat extraction could help to mitigate the low thermal conductivity. The ion-cutting process for heterogeneous integration of a β-Ga 2 O 3 thin film with a highly thermally conductive substrate is an innovative technology for overcoming β-Ga 2 O 3 weak thermal conductivity in nature and realizing β-Ga 2 O 3 full potential in power electronics. Finally, the viewpoint of β-Ga 2 O 3 -based devices for power electronic applications has been analyzed. • An excellent dielectric/semiconductor interface of β-Ga 2 O 3 is essential for optimizing a high power devices performance is extremely important. • Improved ohmic connections by reducing contact resistance through interfacial engineering and interlayers such as conducting oxides of AZO, ITO, and related materials. • For the requirement of large scale transfer of high quality β-Ga 2 O 3 layer and low temperature integration, wafer bonding between β-Ga 2 O 3 and high-thermal-conductivity substrates at low temperature seems to be an appropriate solution using a surface activated bonding (SAB) method. • Heterogeneous integration of high-quality β-Ga 2 O 3 thin films onto high-thermal-conductivity substrates has been recognized as a promising approach to overcoming Ga 2 O 3 electronics thermal limitations. • It paves a new path to solving the problem of self-heating in β-Ga 2 O 3 power electronic devices and encourages the use of β-Ga 2 O 3 in industry.