Effect of Moisture Stress on the Resistance of HfO2/TaOx-Based 8-Layer 3D Vertical Resistive Random Access Memory

Non-filament 3D vertical random access memory (VRRAM) is a promising technology for emerging high-density memory applications, which can significantly improve system performance by simplifying memory hierarchy. Reliability issue is one of the most challenging concerns precluding the commercial application of RRAM. The bulk of RRAM reliability papers focus on the electric stress, while the effect of moisture stress from ambient environment has seldomly been studied. In this brief we examine the aging kinetics of moisture stress through statistical measurements on state-of-the-art 8-layer 3D VRRAMs. The results reveal that R-HRS and on/off window declines significantly while R-LRS remains unaltered in terms of the average value of multiple devices. Meanwhile, reset current Ireset increase obviously. Moreover, different layers exhibit the same aging kinetics. We speculate the observed degradation is due to the moisture stress introduces defects at HfO2/TaOx interface and brings down the barrier.