Influence of discharge current on phase transition properties of high quality polycrystalline VO₂ thin film fabricated by HiPIMS

To fabricate high-quality polycrystalline VO₂ thin film with a metal-insulator transition (MIT) temperature less than 50 °C, high-power impulse magnetron sputtering with different discharge currents was employed in this study. The as-deposited VO₂ films were characterized by a four-point probe resistivity measurement system, visible-near infrared (IR) transmittance spectra, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy. The resistivity results revealed that all the as-deposited films had a high resistance change in the phase transition process, and the MIT temperature decreased with the increased discharge current, where little deterioration in the phase transition properties, such as the resistance and transmittance changes, could be found. Additionally, XRD patterns at various temperatures exhibited that some reverse deformations that existed in the MIT process of the VO₂ film, with a large amount of preferred crystalline orientations. The decrease of the MIT temperature with little deterioration on phase transition properties could be attributed to the reduction of the preferred grain orientations.