Integrations and applications of gallium oxide and diamond

Advances in technology drive transformative evolutions in next-generation semiconductor systems and multifunctional devices. Among ultrawide bandgap semiconductors (UWBG), Ga 2 O 3 ( E g = 4.9 eV) has emerged as a promising candidate for high-voltage power electronics (>10 kV) and solar-blind ultraviolet detection, owing to its exceptional breakdown field strength (10 MV/cm) and superior Baliga figure of merit (>3000 × silicon). However, the low thermal conductivity (<30 W·m −1 ·K −1 ) and the difficulty in achieving effective p-type doping limit the practical applications of Ga 2 O 3 . As another UWBG, diamond has the highest thermal conductivity (>2000 W·m −1 ·K −1 ) among all known bulk materials and p-type doping ability, while both of which are not achievable in Ga 2 O 3 . It can be predicted that the integration of the two materials not only ameliorates thermal management issues in Ga 2 O 3 devices, but also enables the realization of novel pn heterojunction architectures. This review summarizes the recent achievements in Ga 2 O 3 /diamond integration methods, as well as the applications of Ga 2 O 3 /diamond heterogeneous systems. Furthermore, the key challenges and future research directions are also discussed at the end of the article. • Gallium oxide and diamond integration solves critical thermal issues in power electronics. • Novel pn junction diodes created using n-type gallium oxide and p-type diamond materials. • Three methods enable integration: material transfer, diamond growth on oxide, oxide growth on diamond. • Integrated devices achieve high breakdown voltages and efficient solar-blind ultraviolet light detection. • Diamond substrate boosts thermal conductance by over 100 times compared to gallium oxide alone.