Ultrathin (<10 nm) Electrochemical Random‐Access Memory that Overcomes the Tradeoff between Robust Weight Update and Speed in Neuromorphic Systems

Electrochemical random‐access memory (ECRAM) devices are a promising candidate for neuromorphic computing, as they mimic synaptic functions by modulating conductance through ion migration. However, the use of a thick electrolyte layer (>40 nm) in conventional ECRAMs leads to an unavoidable tradeo...

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Bibliographic Details
Main Authors: Seonuk Jeon, Seokjae Lim, Nir Tessler, Jiyong Woo
Format: Article
Language:English
Published: Wiley 2025-08-01
Series:Advanced Intelligent Systems
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Online Access:https://doi.org/10.1002/aisy.202500416
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Summary:Electrochemical random‐access memory (ECRAM) devices are a promising candidate for neuromorphic computing, as they mimic synaptic functions by modulating conductance through ion migration. However, the use of a thick electrolyte layer (>40 nm) in conventional ECRAMs leads to an unavoidable tradeoff between synaptic weight updates and operating speed. To address this problem, a Cu‐based ultrathin ECRAM (UT‐ECRAM) that uses a single 5 nm HfOx active layer and a ≈1.2 nm AlOx liner is designed. The highly efficient gate‐tunable fast Cu‐ion transport in the AlOx/HfOx UT‐ECRAM enables 1) near‐ideal linearity in weight updates (0.45) even achieved with a pulse width (tw) of 50 μs, 2) dynamic multilevel retention of 104 s, and 3) reliable cycling endurance of 104 cycles. A numerical analysis based on device scaling quantitatively reveals that a relatively high concentration of field‐driven Cu ions (≈1020 cm−3) contributes to each synaptic weight update per gate voltage (VG) pulse in the UT‐ECRAM without becoming deactivated by traversing thicker layers. This improved gate sensitivity can ultimately overcome the linearity and the ratio/speed tradeoff relationships, paving the way for robust neuromorphic synaptic units.
ISSN:2640-4567