Ion Gel-Gated IGZO FETs with Al2O3 Interlayer for Low-Leakage Neuromorphic Devices

초록

Indium-gallium-zinc-oxide (IGZO) field-effect transistors (FETs) using an ion gel gate dielectric layer show great promise for neuromorphic computing owing to their memory functions. Here, we demonstrate ion gel-gated IGZO FETs exhibiting low leakage current level and neuromorphic behaviors by introducing an Al2O3 interlayer between the ion gel gate dielectric and source/drain/gate electrodes. It was observed that the Al2O3 interlayer effectively reduced the off-state drain current level and counterclockwise hysteresis behavior. Particularly, the IGZO FETs with the Al2O3 interlayer exhibited off current level of ∼10-11 A and corresponding on/off ratio of ∼107. Meanwhile, IGZO FETs without the Al2O3 interlayer showed negligible current switching characteristics owing to high leakage current between source and drain electrodes. Additionally, the ability to tune the synaptic weight through gate bias-dependent modulation enabled the emulation of artificial neural network, as evidenced by a 90.63 % recognition accuracy on the MNIST database. These results suggest that the ion gel-gated IGZO FETs have significant potential in realizing efficient and scalable neuromorphic computing.

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