【Epitaxy Papers】Phase transformation of gallium oxide thin films with deposition temperature grown on a c-plane sapphire substrate using an in-house built mist CVD setup

      Researchers from the IIT Mandi have published a dissertation titled "Phase transformation of gallium oxide thin films with deposition temperature grown on a c-plane sapphire substrate using an in-house built mist CVD setup" in Vacuum.

Abstract

      Recently, gallium oxide (Ga₂O₃) has emerged as a promising material for power electronics due to its exceptional electrical and optical properties. Among the different crystal phases of Ga₂O₃, α-Ga₂O₃ and β-Ga₂O₃ have gained significant attention for their wide bandgap and high electric field breakdown strength, making them ideal for high-power and high-temperature applications. This article presents a comprehensive investigation into the mist chemical vapor deposition (Mist CVD) technique for the growth of α-Ga₂O₃ films, focusing on its phase transition to the β-Ga₂O₃ with the increase in the deposition temperature. The X-ray diffraction (XRD) analysis reveals the transition of phase in the Ga₂O₃ thin film from a pure phase α-Ga₂O₃ to a mixed phase α-Ga₂O₃ and β-Ga₂O_3, and then to pure phase β-Ga₂O₃ when the deposition temperature rises from 500 °C to 550 °C and then to 600 °C. Morphological investigation demonstrates a heteroepitaxial growth of Ga₂O₃ thin film at 500 °C and 550 °C temperatures and changes to polycrystalline film with further increase in the deposition temperature. Micron-scaled films of Ga₂O₃ have been achieved within 25 min of deposition time. An increase in the surface roughness to 6.79 nm has been observed for the film deposited at 600 °C.

DOI：

https://doi.org/10.1016/j.vacuum.2025.114451