Energy-Efficient Artificial Synapses Based on Flexible ... - IEEE Xplore

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IEEE ELECTRON DEVICE LETTERS, VOL. 36, NO. 2, FEBRUARY 2015

Energy-Efficient Artificial Synapses Based on Flexible IGZO Electric-Double-Layer Transistors Jumei Zhou, Ning Liu, Liqiang Zhu, Yi Shi, and Qing Wan

Abstract— Flexible low-voltage indium-gallium-zincoxide (IGZO) electric-double-layer transistors are fabricated on polyethylene terephthalate substrates at room temperature and proposed for energy-efficient artificial synapse application. The IGZO channel conductance and the gate voltage pulse are regarded as synaptic weight and synaptic spike, respectively. The energy consumption of our IGZO synaptic transistor is estimated to be as low as ∼0.23 pJ/spike. Short-term synaptic plasticity and high-pass filtering behaviors are also mimicked in an individual IGZO synaptic transistor. Index Terms— IGZO electric-double-layer transistors, artificial synapse, biological filter.

I. I NTRODUCTION UR brain contains ∼1011 neurons, and each neuron is connected with other neurons through 103 ∼104 synapses [1]. Such synaptic integration makes our brain has a significant computational ability [2]. Energy consumption for brain computation is only ∼20 W and the power dissipation for single synaptic event is in the order of ∼10−13 W [3], [4]. Biomimetic hardware realization of synapses by solid-state devices with low energy dissipation is critical for braininspired computation, brain-computer interface, and biomimic sensor applications. Recently, resistive switching memories and memristors were proposed for artificial synapses. Low energy dissipation