Novel bipolar TaOx-based Resistive Random Access Memory

In this paper, we report a novel Cr/TaO_x/Al (top to bottom) Resistive Random Access Memory (RRAM) which works as a bipolar switching device. The RRAM devices have demonstrated excellent memory performance including small magnitude of switching voltages (about 2 V), a tight distribution of V_set and V_reset, low switching current, large off/on resistance ratio R of up to 10⁷, and good retention characteristics (more than 10⁵ s) at high temperature (120°C). Resistance of both states shows little degradation, and retention characteristics can be extrapolated to 10 years. The relationship between active area and resistance at low resistance state is studied and the switching appears to be a local phenomenon which is likely to be of the filament type. Forming gas anneal has an additional positive effect on the device performance parameters, as it leads to smaller magnitude of switching voltages and better uniformity of the resistance in the high resistance state.