Resistive switching performance and synaptic behavior of La-doped HfO2 thin film

Abstract

Resistive random-access memory has great application prospects in developing nonvolatile memory and artificial synapse devices. In this work, lanthanum (La) doped hafnium dioxide (HfO2) (La: HfO2) thin film is fabricated by sol-gel deposition. Using gold (Au) and lanthanum nickelate (LaNiO3) as electrodes, the resistive switching performance and synaptic behavior of memristor based on La: HfO2 thin films with different doping concentrations as resistive switching layers are investigated. Current-voltage characteristics show that La-doped devices all exhibit bipolar resistive switching performance. When La doping concentration is 10%, the device shows reliable switching ratio (∼103) under 110 consecutive cycles. And the conduction mechanism of the device in high resistance state and low resistance state is analyzed by ohmic conduction and space charge limited conduction. In addition, the analog resistive switching can be obtained by increasing the voltage scanning and the result reveals that the device can be used to mimic the potentiation and depression behavior of biological synapses. Au/10% La: HfO2/LaNiO3/Si memristor effectively simulates the synaptic properties, such as long-term potentiation/depression, short-term potentiation/depression, paired-pulse facilitation and spike-time-dependent-plasticity learning rule. Furthermore, the information is classified and processed in an 8×8 pixel array. These findings will open up a unique way for the future development of nonvolatile memory and neural morphology computation.