Designing High-Performance Storage in HfO2/BiFeO3 Memristor for Artificial Synapse Applications

HfO2-based memristors that remembers the history of the current that has passed through them have attracted great interest for use as artificial synapses in neuromorphic systems. However, the low resistance contrast exhibited by HfO2-based memristors seriously decreases their recognition accuracy. By inserting a 2 nm BiFeO3 layer a large memory window of 10(4) and remarkable pulse endurance of 10(8) cycles are achieved. Multilevel storage capability is also demonstrated by controlling the stop voltages in the RESET process. The conductance-modulation characteristics of a BiFeO3/HfO2 memristor can be used to mimic the learning behaviors of biological synapses, and spiking timing dependent plasticity is mimicked, which is viewed as an important learning rule of biological synapses. Moreover pattern learning and memorization ability like the human brain are achieved by a 3 x 3 memristive device array.