Long-term and short-term plasticity of Ta2O5/HfO2 memristor for hardware neuromorphic application

Here in, we introduce a Pt/Ta2O5/HfO2/TiN memristor with enhanced resistive switching behavior, these conductive effects were induced by inserting a HfO2 layer. We demonstrate that the uniform switching performance of the Pt/Ta2O5/HfO2/TiN device comes from the construction and destruction of oxygen vacancies (ion generation) in the HfO2 film. Low-power response of the analog conductance changes with different dynamic synaptic characteristics were demonstrated, which included paired-pulse depression (PPD), long-term potentiation (LTP), long-term depression (LTD), and spike timing-dependent plasticity (STDP). This was achieved by the proper adjustment of pulse amplitude, width and interval. Furthermore, the pattern recognition accuracy of a system was evaluated which composed in the device by forming a 3-layer neural network (784 × 128 × 10) with Ta2O5/HfO2 based memristor synapses. The experimental research with proposed Pt/Ta2O5/HfO2/TiN memristor provides valuable insight for the optimization of synaptic performances to use in futuristic neuromorphic applications.