Elucidating Ionic Programming Dynamics of Metal‐Oxide Electrochemical Memory for Neuromorphic Computing. (17th June 2021)

• Record Type: Journal Article
• Authors: Jeong, Yangho; Lee, Hyunjoon; Ryu, Da Gil; Cho, Seong Ho; Lee, Gawon; Kim, Sangbum; Kim, Seyoung; Lee, Yun Seog
• Is Part Of: Advanced Electronic Materials. Volume 7:Number 8(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-06-17
• Subjects: artificial analog synapse -- electrochemical memory -- ionic transport -- metal‐oxide -- neuromorphic computing; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202100185
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: Cross‐point arrays of synaptic devices have been investigated as a core platform for neuromorphic computing architectures. To achieve a significant speed boost in deep neural network computations compared to the von Neumann architecture, it is essential to develop synaptic devices with optimal performance for fully parallel vector‐matrix‐multiplication. Among various non‐volatile memory candidates, metal‐oxide based electrochemical random‐access memory (ECRAM) is considered as a promising analog synapse due to its superior switching characteristics and CMOS‐compatibility. However, the switching mechanisms of metal‐oxide ECRAM remain to be understood, impeding improvements of the synaptic characteristics and device performance. Here, ionic programming dynamics based on oxygen ion migration and associated redox‐reactions are investigated in metal‐oxide ECRAMs by considering ion transport via the electrolyte and diffusion in the channel. Additionally, the origins of update asymmetry and long‐term retention found in voltage‐pulse programming measurements are explained by non‐uniform distribution of the off‐stoichiometry in the channel layer. By exploiting the programming mechanism, ECRAMs can achieve desirable synaptic characteristics under voltage‐pulse mode. Finally, experimental and simulation studies consistently suggest that channel and electrolyte with high ionic transport properties can improve the performance of metal‐oxide ECRAMs, opening a path toward optimized synaptic device characteristics for the maximum computation performance. Abstract : Ionic programming dynamics in a metal‐oxide electrochemical memory comprising a HfO2 electrolyte and a WO3− x channel is unraveled with ionic migration and diffusion model. Exploiting the operating mechanism, this memory device can achieve highly linear and symmetric conductance response under voltage‐pulse mode as well as a programming selectivity toward large‐scale and high‐performance neuromorphic computing devices.