Novel a-IGZO Anti-Ferroelectric FET LIF Neuron with Co-Integrated Ferroelectric FET Synapse for Spiking Neural Networks

Abstract

For the first time, a novel amorphous-Indium-Gallium-Zinc-Oxide (a-IGZO) anti-ferroelectric field-effect transistor (AFeFET)-based leaky integrate-and-fire (LIF) neuron is experimentally demonstrated, emulating both excitatory and inhibitory input connections with capacitor-free neuron design. By co-integrating a-IGZO ferroelectric field-effect transistors (FeFETs) as synapses, spiking neural networks (SNNs) with high biomimetic and low hardware costs could be implemented. The highlights of this work include: (1) high-performance AFeFET with channel length $(L_{CH})$ down to 50 nm and endurance of more than $10^{9}$ cycles is realized; (2) the inherent volatile feature of AFE HfZrO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (HZO) and ferroelectric dynamic switching offer the flexibility to leverage the leaky and accumulation effects by adjusting the base voltage $(V_{B})$ of input pulses; (3) a-IGZO AFeFET neuron and non-volatile FeFET synapse with the same metal-ferroelectric-metal-insulator-semiconductor (MFMIS) structure and optimized memory window (MW) are successfully integrated; (4) using the experimentally calibrated neuron and synapse models, an unsupervised SNN employing the spike-timing-dependent plasticity (STDP) method is simulated, achieving 91.4% accuracy in digit recognition.