Effect of argon-oxygen ratios on crystallization and surface morphology of gallium oxide thin films by low-pressure chemical vapor deposition

β-Ga₂O₃ thin films were heteroepitaxially grown on AlN(0001) substrates via low-pressure chemical vapor deposition (LPCVD). A comprehensive investigation was conducted to characterize the crystalline structure, surface morphology, and chemical composition of both the deposited films and heterostructures. X-ray diffraction (XRD) analysis revealed that the β-Ga₂O₃ films exhibited phase purity with a highly preferred (-201) growth orientation. The surface topography evolution under various growth conditions was systematically examined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) measurements demonstrated an optimal Ga/O atomic ratio of 1.5, confirming the formation of stoichiometric Ga-O bonding configurations. These findings substantiate the feasibility of fabricating high-quality β-Ga₂O₃ films with superior physical properties through LPCVD heteroepitaxy on AlN substrates, thereby establishing a crucial foundation for developing next-generation Ga₂O₃-based power electronic devices.