Mist CVD-based growth of crystalline alpha chromium oxide (α-Cr2O3) on c-plane sapphire substrate with chromium acetylacetonate as a precursor

α -Cr 2 O 3 is used as a buffer layer for the growth of α -Ga 2 O 3 on sapphire for power devices. Presently, the growth of crystalline corundum-structured metal oxides layers, except for α -Cr 2 O 3 , is performed with metal acetylacetonates. This article investigates the development of a crystalline α -Cr 2 O 3 thin films on c -plane sapphire with chromium acetylacetonate (CrAc) as precursor over a wide temperature range varying from 400 to 550 °C. The temperature range not only ensures the compatibility of the process with α -Ga 2 O 3 technology but also satisfies the requirement that the window is large enough to adequately optimize the quality of crystalline α -Cr 2 O 3 thin film. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were performed to analyse the quality of the crystalline α -Cr 2 O 3 layer. The XPS result showed that the ratio of different oxidation states of α -Cr 2 O 3 changes with deposition temperature. An optimal deposition temperature at 500 °C with the molarity of CrAc being 0.05 M is achieved for better quality α -Cr 2 O 3 thin film deposition. Thin film of α -Cr 2 O 3 of thickness 530.5 nm has been deposited at optimal condition with a deposition rate of 35.37 nm/min and has a crystallite size of 31.21 nm and root mean square value of surface roughness of 0.647 nm.