氧化钒薄膜的微结构及阻变特性研究

采用射频反应溅射法于室温下在Cu/Ti/SiO₂/Si基底上制备了氧化钒薄膜. X-射线衍射、X射线光电子能谱分析仪及原子力显微镜结果表明, 室温下制备的氧化钒薄膜除微弱的V₂O₅ (101)和V₂O₃ (110)峰外, 没有明显的结晶取向, 是VO₂, V₂O₅, V₂O₃及VO的混合相薄膜, 且薄膜表面颗粒大小均匀, 表面均方根粗糙度约为1 nm. 采用半导体参数分析仪对薄膜的电开关特性进行测试. 结果表明薄膜具有较低的开关电压(V_Set<1 V, V_Reset<-0.5 V), 并且具有稳定的可逆开关特性. 薄膜从低阻态转变为高阻态的电流(I_Reset)随限流的增大而增大.通过高低阻态时I-V对数曲线的拟合(高阻态斜率>1, 低阻态斜率=1), 认为Cu离子在薄膜中扩散形成的导电细丝是该体系发生电阻转变的主要机制.关键词：氧化钒薄膜电阻开关电阻式非挥发存储器导电细丝

Micro-structural and resistive switching properties of vanadium oxide thin films

Vanadium oxide thin films are deposited on Cu/Ti/SiO₂/Si by reactive sputtering at room temperature. The crystal structure, component and surface morphology of VO_x film are characterized by X ray diffraction, X-ray photoelectron spectroscopy and atomic force microscopy, respectively. These investigations reveal that there is no obvious crystal orientation except weak V₂O₅ (101) and V₂O₃ (110) peaks, and the film contains VO₂, V₂O₅, V₂O₃ and VO mixture phase. The surface particle size of the film is uniform with a root mean square roughness of 1 nm. The resistive switching properties of VO_x thin film are tested by semiconductor device analyzer (Agilent B1500A). The I-V characteristics of the VO_x memory cell reveal that the cell has low switch voltage (V_Set<1 V, V_Reset<0.5 V) and the stable reversible switching characteristic. The current of the film changing from low resistance state to high resistance state (I_Reset) increases with current compliance increasing. The double-logarithmic plots of the I-V curve for the high and low resistance state show high configuration slope >1 and low resistance state slope=1. It is confirmed that the copper ion diffusion and the formation of conduction filaments may be the resistance switching mechanism of the VO_x/Cu structure.