The chronic degeneration mechanism of NbOx-based artificial neurons in the active state

Abstract

The stable operation of the neuromorphic system is significantly constrained by the response imbalance of artificial neurons, which originates from the degradation of devices as switching voltage shift (SVS). In this Letter, we systematically investigate the chronic degradation mechanism of the NbOx threshold switching (TS) device in integrate-and-fire (LIF) neurons by sustained operations. The SVS of the device is solidly verified and attributed to the changes of the TS region. Particularly, the biased evolution of the TS region diameter during operation dominates the different SVS in the reverse response. This reveals the irreversible degradation of the devices and neurons and further demonstrates their limited self-repair ability by implementing symmetric pulse stimulation. This work clarifies the SVS mechanism of NbOx-based TS devices in LIF neurons, providing support for extending neuronal lifespan and developing reliable neuron-based hardware.