Studies on Resistive Random Access Memory (RRAM) device performance using oxygen affinity of metal electrodes and Light-induced resistive switching

Resistive Random Access memory (RRAM) devices have drawn great attention as next generation non-volatile memory due to significant advantages over other memories such as flash and DRAMs. RRAM technology displays many merits like non-volatility, fast switching, high endurance and retention and no physical constraints on small feature size which was a great issue in the transistor based memories. Further improvement in RRAM switching performance required to compete with the present memory technology. In the present work we able to improve the RRAM device performance by two means. One is by using electrodes with different oxygen affinities and another is by means of light-induced resistive switching. Metal-insulator-metal structures with CuxO switching layer and Al, Cr or Ni top electrodes with Au or Pt as the bottom electrode were fabricated. The Vset, Vreset and Preset values decrease whereas the Ireset value increases with increase in oxygen affinity. A figure of merit which includes all the switching parameters is introduced to compare the device structures. The figure of merit is highest for devices fabricated with the lowest oxygen affinity metal (Ni). Devices fabricated with Ni as top electrode and Pt bottom electrode showed poorer set and reset performance than the device with Au as bottom electrode. However, these devices showed better endurance and throughput in addition to retention for more than 104 s for both the states. This study clearly demonstrates that oxygen affinity of metal electrodes (OAME) is an important control parameter in tuning the performance of resistive random access memories. Set and reset voltages can be controlled by light-induced resistive switching thereby enables low power and stable device. It’s reduced the set voltage to 50 mV from 2.5 V and reset was occurred 16 mV which is 150 times smaller than the convention reset voltage.