CMOS-Compatible Protonic Three-Terminal Memristor for Analog Synapse in Neuromorphic Computing

All-solid-state inorganic hydrogen-based three-terminal memristors (H-3TMs) suffer from poor retention, susceptibility to humidity and temperature, and the reliance on wet chemistry during fabrication, hindering their manufacturability within existing foundry processes. To address these, this study presents a CMOS-compatible H-3TM based on reversible intercalation and extraction of protons between the SiN_x electrolyte and WO_x channel. The protons are introduced via a straightforward hydrogen plasma treatment, promoting a compatible fabrication process with back-end-of-line integration. Experimental and simulation results indicate that the low proton transport tendency across the electrolyte/channel interface without an external electric field contributes to high retention performance. Furthermore, the device demonstrates linear potentiation and depression, 512 conductance states with a dynamic range of ≈40, low energy operation (≈73 fJ per write), and excellent overall device-to-device variation. Its analog properties are evaluated under the training and inference framework of MNIST and Fashion-MNIST datasets. The device achieved training and inference accuracies only 0.4% and 0.3% below the ideal benchmark on the F-MNIST dataset. This work offers a rational approach for future artificial synaptic device design and fabrication.