Growth and electrical properties of vanadium-dioxide thin films fabricated by magnetron sputtering

Single crystalline vanadium-dioxide (VO₂) thin films on sapphire (0001) have been grown by using a radio-frequency (rf) magnetron sputtering technique. The dependences of the resistivity change and the hysteresis width of the VO₂ thin films on the oxygen flow ratio [= O₂× 100/Ar+O₂ (%)] at a fixed deposition temperature of 550 °C have been studied. The VO₂ film grown at an oxygen flow ratio of 3.85 % showed a metal-to-insulator transition around ∼65 °C with a resistivity ratio as high as 4.3 × 10³ and a hysteresis width of ∼6 °C. Moreover, the VO₂ film, thermally cycled of up to 100 times across the transition temperature, was found to be stable; i.e., no noticeable changes in the magnitude of the resistivity and in the shape of the hysteresis curve were observed.