Abstract: As an ultra-wide bandgap semiconductor material, β-Ga₂O₃ has a broad application prospect in power devices. This work proposes a new method for fast epitaxial growth of crystalline β-Ga₂O₃ thick films: the suboxide chemical vapor transport (SOCVT), which has the advantages of simple operation and cost-effective. Using gaseous Ga₂O generated by the high-temperature reaction of liquid Ga and solid Ga₂O₃ as the Ga source, the growth of a β-Ga₂O₃ crystalline film, thicker than 100 μm, on the c-plane sapphire single-crystal substrate (1 cm×1 cm) was achieved in the CO₂ atmosphere at a setting temperature of 1 300 ℃ with the crucible-substrate spacing of 8.5 cm. According to the XRD analyses, the sample has a preferred orientation of (201). The SEM characterizations show that the deposited thick film is uniform and dense, with a thickness of 106.4 μm. XPS analyses reveal that the element O/Ga ratio of the thick film is 1.5, indicating its high chemical purity with no carbon-doping. The bandgap estimated from optical transmission spectrum is 4.42 eV. The research results indicate that the SOCVT technique offers a fast growth rate of β-Ga₂O₃, which is expected to become a new method for cost-effective and fast growth of crystalline β-Ga₂O₃ thick films.

Key words: suboxide chemical vapor transport, β-Ga₂O₃, thick film, cost-effective, ultra-wide bandgap semiconductor