氧化钒薄膜的制备及电致开关特性的研究

Preparation and resistive switching properties of VO_x thin films

采用反应溅射法,室温下,在Cu/Ti/SiO2/Si衬底上制备了氧化钒（VOx）薄膜,并对薄膜进行450℃、30min的真空退火处理。采用X-射线衍射（XRD）、原子力显微镜（AFM）对薄膜的结晶取向和表面形貌进行了表征,通过半导体参数分析仪对薄膜的电开关特性进行测试,并利用导电原子力显微镜（CAFM）对VOx薄膜的导电机制进行了探索。测试结果表明,VOx薄膜在Cu/Ti/SiO2/Si衬底取向生长,并且是以V2O5为主的V6O13和V2O5的混合物,薄膜表面颗粒大小均匀（30~40 nm）,粗糙度为2.4 nm。电学测试结果表明薄膜具有较低（Vset=0.72 V,Vreset=0.39 V）的开关电压,开关电阻的转变倍率约3个数量级,经CAFM测试发现,VOx薄膜导电态中有导电细丝,结合VOx/Cu界面态及Cu离子快扩散特性,认为VOx薄膜导电态主要是Cu离子在薄膜中扩散形成的导电细丝所致。

In order to research the electrical resistive switching properties of VOx thin films,the thin films were deposited by reactive sputtering on Cu/Ti/SiO2/Si substrates at room temperature and annealed at 450 ℃ for 30 min in vacuum atmosphere.The crystal structure and surface morphology of VOx films were characterized by X-ray diffraction（XRD） and atomic force microscopy（AFM）.The electrical property of VOx thin films were tested by Semiconductor Device Analyzer（Agilent B1500A）,the conduction mechanism was explored by conductive atomic force microscopy（CAFM）.XRD results show that the VOx thin films were crystallized preferably and were composed of V6O13 and V2O5 two oxidation phases.AFM results indicated that the VOx thin films were of the homogeneous particle（30～40 nm） and with the RMS roughness of 2.4 nm.I-V characteristic of the VOx memory units revealed the low power possibility with the low Vset（0.72 V） and Vreset（0.39 V）,and three orders of change in resistivity was observed.CAFM figures illustrated the conduction filament mechanism for VOx thin films,and the copper ion diffusion and the formation of conduction filament may be used to explain the above resistance switching mechanism.