Oxygen Affinity of Metal Electrodes as Control Parameter in Tuning the Performance of Cu < inf > x < /inf > O-Based Resistive Random Access Memory Devices

Abstract

CuxO-based resistive random access memory (RRAM) devices are fabricated with low, medium, and high oxygen affinity metals as the top electrode and gold and platinum as the bottom electrode. Switching performance of the device with varying oxygen affinity is observed. The variation, mean, and the cycle percentage of Vset and Vreset values decrease with the decrease in oxygen affinity but increase in the case of Ireset. The reset power parameter decreases with oxygen affinity of metal electrodes (OAME). A generalized figure of merit (FM), which considers all the parameters (variation, mean, and cycles count) of a switching parameter (Vset, Vreset, Ireset, and Preset), is introduced to explain the performance. The FM also confirms the variation in switching parameters with oxygen affinity. This reveals that the performance of the device is improved with the decrease in oxygen affinity. The device fabricated with low oxygen affinity metal electrode, Ni, shows the best performance among all the CuxO-based RRAM devices. Further improvement in device performance is achieved by changing the bottom electrode from Au to Pt with the top electrode being retained as a low oxygen affinity metal. This combination is shown to be the best in terms of retention and endurance.