Formation of multiple conductive filaments in the Cu/ZrO2:Cu/Pt device

We report the direct electrical measurement of multiple resistance steps in the ZrO2-based solid electrolyte nonvolatile memory device using the refined dc I-V method with a very small voltage increasing rate. The results demonstrate that multiple conductive filaments are formed successively between the bottom and top metal electrodes through the insulating layer while increasing the bias voltage, which are consistent with the electrical field simulation results based on the solid electrolyte theory. The inverse relationship between resistance steps and the filament formation sequence are obtained, which helps understand the switching mechanism of the multiple conductive filaments.