Resistive Switching of Al/Sol-Gel ZnO/Al Devices for Resistive Random Access Memory Applications

Unipolar resistive switching devices are investigated for non volatile memory applications in a metal-insulator-metal structure in which the insulator layer consists of sol-gel-derived zinc oxide (ZnO) films prepared by a simple spin-coating process followed by thermal annealing. A high off-to-on resistance ratio (>10²) is demonstrated. The influence of device area on the device is studied to suggest a mechanism for the resistive switching. The effect of annealing temperature on crystallinity and thus switching behavior is studied. In addition, the memory characteristics are studied as a function of ZnO film thickness. The devices exhibit reproducible resistive switching and good retention time, demonstrating their potential for low-cost non volatile memory applications in the future.