Conduction mechanism and synaptic behaviour of interfacial switching AlO_σ-based RRAM

Analog resistive switching (ARS) is an important characteristic of resistive random-access memory (RRAM) used as a synaptic device. An interface switching cross-point RRAM was fabricated with Au/TiOx/AlOσ/Al stacked structure in order to investigate its conduction mechanism and synaptic behaviour. The gradual resistive switching characteristic of the fabricated AlOσ-based RRAM was demonstrated and the ARS conduction mechanism was analyzed by using the DC sweep technique. The I-V relationship shows that the conduction mechanism in the RESET state is governed by Schottky conduction, which was confirmed by a linear relationship from the Log (I) vs. Sqrt (V) graph, while the conduction mechanism in the SET state is governed by Poole-Frenkel conduction, which was confirmed by a linear relationship from the Log (I/V) vs. Sqrt (V) graph. This AlOσ-based device also showed long-term potentiation and long-term depression characteristics, which are crucial in developing convolutional neural networks based neuromorphic systems, by using identical pulse series. The experimental results demonstrate that mimicking the synaptic characteristics of the neuromorphic systems would be possible with an interface switching cross-point AlOσ-based RRAM device with Au/TiOx/AlOσ/Al layer.