(Invited) Thermodynamics of Oxygen Transport in Resistive and Electrochemical Memory

Many neuromorphic computing architectures contain emerging memory devices that function through oxygen migration. Examples include resistive memory 1 (ReRAM) and electrochemical memory 2 (ECRAM), where tuning the distribution of oxygen vacancies enables analog information states. In this presentation, we discuss how oxygen transport in many metal oxides do not obey the drift-diffusion equation, which assumes ideal solution thermodynamics. Instead, the metal oxides undergo composition phase separation into oxygen-rich and oxygen-poor phases. This phase separation explains the long information retention time of ReRAM 3 . We further use this phase separation to improve the information retention time of oxygen-based ECRAM 4,5 by at least ten orders of magnitude, yielding the highest temperature analog nonvolatile memory. References: Dittmann, R., Menzel, S. & Waser, R. Nanoionic memristive phenomena in metal oxides: the valence change mechanism. Adv. Phys. 70 , 155–349 (2022). Talin, A. A., Li, Y., Robinson, D. A., Fuller, E. J. & Kumar, S. ECRAM Materials, Devices, Circuits and Architectures: A Perspective. Adv. Mater. (2023) doi:10.1002/adma202204771. Li, J. et al. Thermodynamic origin of nonvolatility in resistive switching . https://www.researchsquare.com/article/rs-2365752/v1 (2022) doi:10.21203/rs.3.rs-2365752/v1. Li, Y. et al. Filament-Free Bulk Resistive Memory Enables Deterministic Analogue Switching. Adv. Mater. 32 , 2003984 (2020). Kim, D. S. et al. Nonvolatile Electrochemical Random-Access Memory under Short Circuit. Adv. Electron. Mater. 9 , 2200958 (2023).