Growth of 2-Inch Wafer-Scale Uniform Vanadium Dioxide Thin Films Using Radio-Frequency Sputtering System and Characteristics of Their Metal-Insulator Transition

摘要

We successfully grow epitaxial VO2 thin films on (0001) Al2O3 substrates by precisely controlling the oxygen flow rate using a radio-frequency magnetron sputtering system. Epitaxy at the interface between the VO2 film and the Al2O3 substrate is verified using high-resolution transmission electron microscopy. We demonstrate that highly desirable material properties can be obtained with the VO2 films that exhibit a high resistivity ratio, excellent uniformity across a 2-inch wafer, and high yield. We systemically investigated how the channel dimensions in two-terminal VO2-based transistors affect the electric-field-induced metal-insulator transition in terms of on-state current density, on-state resistivity, and break-over voltage. Our results can be used to transform VO2-based functionalities into viable technologies that directly impact different applications such as thermochromics, memory metamaterials, or ultrafast switching devices.