Substrate effect on the neuromorphic function of nanoionics-based transistors fabricated using WO3 thin film

Abstract

This paper reports a systematic study on the device characteristics of neuromorphic transistors fabricated by using RF magnetron sputtered WO3 thin film as a channel layer upon atomically flat Si (100), Si (111) and glass substrates. The synaptic behaviour such as learning and forgetting, which are related to short term memory (STM) and memorizing, related to long term memory (LTM) have been demonstrated based on nanoionics phenomena. The conductance modulation using gate-voltage application conditions controls the synaptic behaviour. The switching period, time between learn and forget, has been optimized with gate voltage of within 3 V for the device fabricated on Si (100) substrate. A systematic investigation of substrate effect on the neuromorphic function of devices fabricated with different substrates reveals that the device fabricated on p-type Si(111) exhibits significantly shorter switching ratio, which makes a possibility to modify the device function by the choice of substrate.