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 VOx 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 VOx thin film are tested by semiconductor device analyzer (Agilent B1500A). The I-V characteristics of the VOx 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 VOx/Cu structure.