This paper reviews the evolution of corundum-structured gallium oxide (α-Ga2O3) semiconductors from crystal growth of single-crystalline films to potential device applications. In spite of thermodynamically metastable phase, high-quality α-Ga2O3 can be grown on sapphire substrates by the use of mist chemical vapor deposition (CVD), or mist epitaxy, allowing low-cost and high performance power devices. N-type conductivity control is achieved by Sn doping with the carrier concentration from 1017 to 1019 cm-3. Marked progress in performance of Schottky barrier diodes (SBDs) has been brought by the development of device structures. The most up-to-date results show on resistance and breakdown voltage of 0.1 mΩ・cm2 and 531 V (SBD1) or 0.4 mΩ・cm2 and 855 V (SBD2), respectively, and the record-low on resistance was demonstrated at the high breakdown voltage. These results encourage the future development of low cost and high performance power devices with α-Ga2O3.
