快速热处理制备相变氧化钒薄膜及其特性研究

采用直流对靶磁控溅射在Si<100>基底上沉积金属V薄膜, 然后分别在纯氧气环境和纯氮气环境下进行快速热处理制备具有 金属-半导体相变特性的氧化钒(VO_X)薄膜, 热处理条件分别为纯氧气环境下430℃/40 s, 450℃/40 s, 470℃/40 s, 450℃/30 s, 450℃/50 s, 纯氮气环境下500℃/15 s. 用X射线衍射仪、X射线光电子能谱、原子力显微镜 和扫描电子显微镜对薄膜的结晶结构、钒的价态和组分以及微观形貌进行分析. 利用四探针薄膜电阻测量方法和THz时域频谱技术分析薄膜的电学特性和光学特性. 结果表明: 金属V薄膜经过纯氧气环境450℃/40 s快速热处理 后形成了具有低相变特性的VO_X薄膜, 升温前后薄膜方块电阻变化幅度达到两个数量级, THz透射强度变化幅度较小. 为了提高薄膜的相变特性, 对制备的VO_X薄膜采用纯氮气环境500℃/15 s快速热处理, 薄膜的相变特性有了明显提升, 相变前后方块电阻变化达到3个数量级, THz透射强度变化达到56.33%.

Preparation and characteristic of phase transition vanadium oxide thin films by rapid thermal process

Metal-insulator phase transition VOx thin film is fabricated on a Si(100) substrate after the metal V thin film,prepared by direct current facing targets magnetron sputtering has been rapidly thermally treated first in pure oxygen environment and then in pure nitrogen environment.The thermal treatment conditions are 430℃/40 s,450℃/40 s,470℃/40 s,450℃/30 s,450℃/50 s in pure oxygen environment and 500℃/15 s in pure nitrogen environment.XRD,XPS,AFM and SEM are imployed to analyze the crystalline structure,valentstate and the components,morphology of the thin film.The electrical and optical characteristic of the thin film are analyzed by the Four-point probe method and THz time domain spectrum technology.Results reveal that after 450℃/40 s rapid thermal treatment in pure oxygen environment the metal V thin film turns into VOx thin film which has low properties of phase transition.Before and after heating,the change of resistivity reaches 2 orders of magnitude and the range of the THz transmission intensity shows smooth change.In order to improve the properties of phase transition,the VOx thin film is treated by 500℃/15 s rapid thermal process in pure nitrogen environment.After that,we find that the thin film shows a good phase transition performance, accompanied by a sheet square resistance drop of above 3 orders of magnitude and a 56.33%reduction in THz transmission intensity.