Resistive switching characteristics of sol-gel derived ZrCeOx thin films for nonvolatile memory applications

Amorphous ZrCeOx thin films were prepared by sol-gel method and the resistive switching (RS) properties of sol-gel derived Al/ZrCeOx/ITO devices were investigated. The influences of annealing temperature, film thickness, and top electrode on the RS properties were also discussed. It was found that the optimized Al/ZrCeOx/ITO device with profound RS performance was 2-layered ZrCeOx under 400 degrees C annealing treatment. After annealing treatment, the improvement in the switching cycles is attributed to the diffusion of In ions from ITO substrate to ZrCeOx film and the increased oxygen vacancies, which would allow the discontinuous ions to fit into the connecting process of the formation of filaments. The influence of thickness on the RS properties was also studied. There was no memory characteristics observed in the devices with 4L and 6L film thickness because no conductive filament was formed. In addition, the conduction mechanism could be classified into ohmic conduction in the low resistance state and space-charge-limited current conduction mechanism in the high resistance state.