Synaptic plasticity and preliminary-spike-enhanced plasticity in a CMOS-compatible Ta2O5 memristor

An artificial synapse that can perform both learning and memory functions was realized using an amorphous Ta2O5 memristor. A Pt/Ta2O5/TiN memristor, with an amorphous Ta2O5 film grown at 100 degrees C, exhibited reliable bipolar switching properties at the various conductance states required for artificial synapse applications; in addition, it exhibited the transmission properties of physiological synapses. Various other synaptic properties were also obtained from the Ta2O5 memristor by modulating the input bias. The metaplasticity of a physiological synapse, which is a preliminary-spike-enhanced synaptic function, was also emulated in the Ta2O5 memristor via the metaplasticity of potentiation/depression and spike-timing-dependent plasticity. The synaptic plasticity and metaplasticity of the Ta2O5 memristor can be understood via the construction and destruction of oxygen vacancy filaments in the memristor. (C) 2019 The Author(s). Published by Elsevier Ltd.