Extensive reliability investigation of a-VMCO nonfilamentary RRAM: Relaxation, retention and key differences to filamentary switching

Vacancy Modulating Conductive Oxide resistive switching devices use electrical modulation of the defect profile to vary the conductance of tunneling barrier, thereby operating with self-rectification and self-compliance. They have been demonstrated to show low switching current with area scalability, indicating non-filamentary switching, and thus making them very promising candidates for high density memory applications. In this work, we report on room temperature and higher temperature retention, with extensive study on parametric dependence - the impact of electrical, material, and process parameters. In addition, we highlight differences with respect to filamentary switching, and suggest directions for improvement.