金属Pt薄膜上二氧化钒的制备及其电致相变性能研究

通过引入SiO₂氧化物缓冲层, 在金属Pt电极上利用射频磁控溅射技术成功制备出高质量的VO₂薄膜. 详细研究了SiO₂厚度对VO₂薄膜的晶体结构、微观形貌和绝缘体–金属相变(MIT)性能的影响. 结果表明厚度0.2 μm以上的SiO₂缓冲层能够有效 消除VO₂薄膜与金属薄膜之间的巨大应力, 制备出具有明显相变特性的VO₂薄膜. 当缓冲层达到0.7 μm以上, 获得的薄膜具有明显的(011)晶面择优取向, 表面平整致密, 相变前后电阻率变化达到3个数量级以上. 基于该技术制备了Pt-SiO₂/VO₂-Au三明治结构, 通过在垂直膜面方向施加很小的驱动电压, 观察到明显的阶梯电流跳跃, 证实实现了电致绝缘体–金属相变过程. 该薄膜制备工艺简单, 性能稳定, 器件结构灵活可应用于集成式电控功能器件. 关键词： 二氧化钒薄膜 相变特性 电致相变 阈值电压

Growth of vanadium dioxide thin films on Pt metal film and the electrically-driven metal–insulator transition characteristics of them

High-quality VO₂ thin films are deposited on the metal platinum (Pt) electrode buffered by silicon dioxide (SiO₂) using radio frequency magnetron sputtering. The effect of the thickness of SiO₂ on the the crystal structure, morphology and metal-insulator transition (MIT) performance of the films are discussed. Results show that SiO₂ buffer layer with a thickness of 0.2 μm can effectively eliminate huge stress between the VO₂ film and the metal film; and the VO₂ thin film with the distinct MIT are deposited. When the buffer layer reaches more than 0.7 μm, the VO₂ film has a distinct (011) preferred orientation, the smooth surface and compact nanostructure, and the resistance change reaches more than three orders of magnitude. At the same time, Pt-SiO₂/VO₂-Au sandwiched structure is achieved to test the current versus voltage curves, in which can be seen several distinct steps of current caused by the voltage perpendicular to the plane of a VO₂ film. The result confirms the electrically-driven metal-insulator transition. Due to the high-quality VO₂ and the flexible device structure, the VO₂/Pt-SiO₂ can be widely used for large-scale integrated electronic control devices.
Keywords： vanadium dioxide film phase transition electrically-driven metal-insulator transition threshold voltage