VOx thin films obtained by ion beam sputtering and oxidation process

Polycrystalline VOx thin films were grown on Si substrates by ion beam sputtering deposition and annealing in oxygen atmosphere, which were prepared for thermal-sensitive material of far infrared (IR) sensors. As the deposition temperature (∼150 °C) is lower compared to that (∼400 °C) used to deposit single phase of VO2, scanning electron microscopy (SEM) morphology indicates that the as-deposited vanadium oxide (VOx) thin films were very smooth in surface and their grains are not able to be resolved. After annealing at higher temperature, the thin films were grown finally into ball-like and skeleton-like grains. The four-probe test presents their sheet resistance and the temperature coefficient of resistance (TCR) of the VOx thin film, which are 50 kΩ/□ and −0.021 K−1 at 30 °C, respectively. In addition, IR absorption in the range of 2-20 μm has been characterized.