Research Progress and Prospect of the Bulk Single Crystal Growth of β-Ga2O3: from 1964 to 2024

Abstract

β-Ga₂O₃ is a promising wide band gap material for power device and solar-blind photodector applications. With continuous contribution to the crystal growth of β-Ga₂O₃, it is important to conclude the progress of crystal growth techniques and the remaining problems of the materials propel the next generation of the power device industry. The size of single crystals becomes larger, the quality of epitaxial films is gradually improved, and the performance of devices has become better. β-Ga₂O₃ is an oxide semiconductor with a large bandgap width of 4.7–4.9 eV and a high breakdown electric field of ≈8 MV cm⁻¹. In this review, the structure, thermal properties, optical properties, and electronic properties of β-Ga₂O₃ are introduced first. Then, the growth methods of bulk β-Ga₂O₃ single crystals are introduced, including the Verneuil method, Czochralski (CZ) method, optical-floating zone (OFZ) method, edge-defined film-fed growth (EFG) method, vertical Bridgman (VB) method, casting method, and the oxide crystal growth from cold crucible (OCCC) method. Crystal growth mechanisms and their respective advantages and disadvantages are discussed. The effects of doping elements on the crystal growth have been highlighted in each method. Finally, the prospect of the growth of large β-Ga₂O₃ single crystals is discussed.