The effect of pulse amplitude on the linearity of the weight update in the HfO2-based memristor

The linearity of the memristor conductivity (or weight) variation affects the training accuracy of analog neuromorphic systems. Usually, the weight update linearity can be achieved by changing the waveform, but this requires the inclusion of additional peripherals in the analog circuit. The paper considers the influence of the signal pulse amplitude on the long-term potentiation of a HfO2-based memristor. It is observed that the pulse amplitude decrease leads to the higher device's linearity. The linearity optimization procedure is shown. Additionally, we consider the effects of unusual conductance changing during consecutive cycles of long-term potentiation and long-term depression with a constant voltage amplitude. We demonstrate the possibility of a linear weight update of the device once identical pulses are applied due to unusual behavior.