Ultrawide
bandgap β-gallium oxide (β-Ga2O3) is emerging as a viable candidate for next-generation high-power
electronics, including Schottky barrier diodes (SBDs) and field-effect
transistors (FETs). This is due to its excellent material properties
such as ultrawide bandgap of 4.6–4.9 eV, high breakdown electric
field of 8 MV/cm, very high Baliga’s figure of merit (BFOM)
and mature technology for large bulk single crystals, and epitaxial
techniques with controllable n-type doping. Ohmic and rectifying metal–semiconductor
contacts on β-Ga2O3 have been developed
over the past decade. This work comprehensively reviews the recent
development of metal–semiconductor contacts on β-Ga2O3. We start with basic concepts of metal–semiconductor
contacts, which is followed by summarizing the current literature
on ohmic and Schottky contacts on β-Ga2O3. Finally, the status of high-power Schottky diode contact on β-Ga2O3 is presented.