Abstract: Halide vapor phase epitaxy (HVPE) is mainly utilized to obtain β-Ga₂O₃ homoepitaxial wafers because of its advantages such as high growth rate and efficient impurity doping controllability. In this paper, the homoepitaxialβ-Ga₂O₃ thick films were grown by a vertical HVPE system. The effects of different growth pressures on the growth rate and epitaxial quality were investigated. It is found thatwhen growing epitaxial β-Ga₂O₃ films of the same thickness, although reducing the growth pressure slows down the growth rate, it can easily obtain high crystalline quality β-Ga₂O₃ thick films with unbroken microstep arrays. The source of unintentional nitrogen impurities in the epitaxial films was analyzed, and the possibility of nitrogen decomposition was ruled out. By adjusting the Ⅵ/Ⅲ ratio, specifically by increasing the oxygen partial pressure, the concentration of nitrogen impurities in β-Ga₂O₃ epitaxial films can be effectively reduced from 8×10¹⁶ cm^-3 to 1×10¹⁶ cm^-3. Finally, 2-inch high-quality HVPE β-Ga₂O₃ epitaxial wafer has been successfully achieved with optimized epitaxial growth parameters. The film thickness and carrier concentration are 15.8 μm and 1.5×10¹⁶ cm^-3, the inhomogeneity of which are 3.6% and 7.6%, respectively.

Key words: HVPE, β-Ga₂O₃, homoepitaxial, growth pressure, N impurity, Ⅵ/Ⅲ radio