快速热处理温度对纳米结构二氧化钒薄膜相变特性的影响

Effects of Rapid Thermal Annealing Temperature on Phase Transition Properties of Nanostructured Vanadium Dioxide Thin Film

采用射频磁控溅射方法在单晶硅基底表面制备了单一相纳米结构二氧化钒(VO_2)薄膜,相变幅度超过2个量级;利用快速热处理设备对VO_2薄膜进行热处理,研究氮气氛下快速热处理温度对VO_2相变特性的影响。通过X射线衍射仪、扫描电子显微镜、高精度透射电子显微镜和四探针测试仪对热处理前后薄膜的结晶结构、表面形貌和电学相变特性分别进行了测试。实验结果表明,快速热处理状态下,温度为300℃时,VO_2薄膜的电阻相变幅度由200倍增加到277倍,但是当温度超过350℃后,相变性能迅速变差,相变幅度由2个量级下降为小于1个量级,当温度超过500℃时,相变特性消失;热处理温度升高的过程中,单斜VO_2(011)结晶结构逐渐消失,薄膜的成分转变为V4O7;快速热处理过程中薄膜内的颗粒尺寸保持不变。研究结果将有助于增强对VO_2薄膜在温度差异大、变化速度快环境中的特性进行分析与应用。

Single phase vanadium dioxide（VO2） thin film was fabricated by radio frequency magnetron sputtering on silicon single crystal, and the transition magnitude was beyond 2 orders. VO2 thin film was treated in nitrogen by rapid thermal annealing. X ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy and four probe method were used to characterize the crystal structure, morphology and electrical properties. Results show that the phase transition properties are affected heavily by temperature at rapid thermal annealing mode. The magnitude of phase transition in sheet resistance increases from 200 to 277 times when rapid thermal annealing at 300 ℃ when the temperature is above 350 ℃, the order of magnitude decreases to lower than 1; while above 500 ℃ the phase transition disappears. The composition of VO2 thin films changes from VO2 to V4O7. SEM results show that the hole structure in film doesn＇t change and the particle size almost keeps the same during annealing at different temperatures. The results are important for VO2 application in environment with fast change of temperature.