Crystallinity-controlled WO3 interlayers in asymmetric contact IGZO memtransistors for energy-efficient neuromorphic computing

초록

Oxide-based memtransistors are promising candidates for neuromorphic hardware owing to their gate-tunable conductance modulation and compatibility with scalable device fabrication. However, achieving low programming energy, linear synaptic updates, and stable resistive switching in oxide memtransistors remains challenging. Here, we report asymmetric-contact indium-gallium-zinc-oxide/tungsten oxide (IGZO/WO3) memtransistors employing a crystallinity-controlled WO3 interlayer. We demonstrate that thermal annealing at 400 degrees C induces a structural transition of the WO3 interlayer from an amorphous to a crystalline phase, enabling more stable resistive switching behavior and energy-efficient synaptic modulation. Compared with amorphous WO3 (a-WO3)based memtransistors, the memtransistor with crystalline WO3 (c-WO3) interlayer exhibits a wider memory window, enhanced cycling endurance, and more reliable conductance modulation. The optimized device successfully emulates key synaptic functions including excitatory postsynaptic current, paired-pulse facilitation, and long-term potentiation/depression, while achieving enhanced update linearity. Furthermore, the cumulative programming energy during the conductance update process is substantially reduced from 8140 nJ to 40.29 nJ using the c-WO3 interlayer, highlighting the advantage of crystallinity-controlled interlayer for energy-efficient neuromorphic computing. System-level neural network simulations further verify the neuromorphic applicability of the optimized device, achieving enhanced recognition accuracy in both handwritten digit recognition and the convolutional neural network-based CIFAR-10 image classification tasks. These results suggest that crystallinitycontrolled WO3 interlayer provides an effective strategy for realizing stable, energy-efficient, and scalable oxide memtransistors for neuromorphic computing.

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