Postcycling Degradation in Metal-Oxide Bipolar Resistive Switching Memory

Resistive switching memory (RRAM) features many optimal properties for future memory applications that make RRAM a strong candidate for storage-class memory and embedded nonvolatile memory. This paper addresses the cycling-induced degradation of RRAM devices based on a HfO2 switching layer. We show that the cycling degradation results in the decrease of several RRAM parameters, such as the resistance of the low-resistance state, the set voltage Vset, the reset voltage Vreset, and others. The degradation with cycling is further attributed to enhanced ion mobility due to defect generation within the active filament area in the RRAM device. A distributed-energy model is developed to simulate the degradation kinetics and support our physical interpretation. This paper provides an efficient methodology to predict device degradation after any arbitrary number of cycles and allows for wear leveling in memory array.