非致冷红外焦平面阵列VO_2薄膜结构和性能研究

Study of Structure and Properties of VO_2 Thin Film for Uncooled IR Focal Plane Array

采用射频磁控反应溅射方法,通过精确地控制氧分压、基底温度等关键工艺参数,沉积出满足非致冷红外焦平面阵列使用的VO2薄膜。解决了以往其它方法制备过程中薄膜相成份较为复杂、薄膜不均匀和电阻温度系数达不到使用要求的问题。利用X射线衍射和X射线光电子谱,分析了薄膜的成分、相结构、结晶和价态情况,用原子力显微镜表征了薄膜的微观结构,分光光度计分析了薄膜在可见到红外波段(500～2500nm)高低温透射率变化情况,对薄膜的电学性能也进行了测量和分析。结果表明VO2薄膜纯度高,结晶好,薄膜的光透射率在波长2000nm处相变前后改变了42%,室温下的方块电阻为26.8kΩ/□,电阻温度系数为2.2%/℃。同时给出了利用X射线光电子谱中钒的V2p3/2特征峰位表征氧化钒相结构的方法。

Vanadium oxide thin films used in uncooled infrared focal plane array are deposited by radio frequency reactive sputtering methods while oxygen partial and substrate temperature are controlled accurately during process experiment. The method has solved the problems the other methods have,such as the complex phase composition,nonuniformity and undesirable resistance temperature coefficient of the thin film. Xray diffraction, Xray photoelectron spectroscopy(XPS)are used to analyze the composition,phase structure,crystalline and valence state of the film. Atomic force spectroscopy is used to identify the film surface morphology,and spectrophotometer to characterize the transmittance change at wave range of 500～2 500nm of the deposited film.The electronic performance of the film is also tested. The results show that the films have high purity,excellent crystallinity. The transmittance change of the film is 42% at wavelength of 2 000nm around its phase transition,the square resistance is 26.8kΩ/□,and the resistance temperature coefficient is2.2%/℃at room tmperature. An easy way to identify phase structure of deposited films with the peak position of V2p3/2 in XPS is proposed.