A Consistent Model for Gradual, Abrupt, and Abnormal Reset Phenomena in Bipolar/ Unipolar Metal Oxide RRAMs

The gradual, abrupt, and abnormal reset transitions have been experimentally demonstrated in resistive random access memories (RRAMs). Yet a compact model that could well explain and reproduce the various observed reset phenomena is still under active exploration due to the various physical processes involved. In this study, we develop a consistent compact model for bipolar/unipolar RRAMs, which can comprehensively explain the gradual and abrupt reset transitions, as well as many abnormal phenomena during the reset processes. These abnormal reset processes include the reverse set during reset (reset failure), a gentle set process after the reset transition, and the reset transition during backward voltage sweeps. In this model, we systematically study the competition between defect generation and recombination processes, the energy barriers for oxygen ion migration into and out of the reservoir layer, and the vacancy concentration of the filament. Based on the model, we experimentally demonstrate tuning of the device switching behavior. This study provides important insights into the reset dynamics and guidelines for predictably controlling RRAM switching behaviors.