Investigation of SiO2-Vo/SiO2 interface induced rectification characteristics at HRS for RRAM devices

In order to solve the read/write mistakes caused by leakage current, it is desirable to add a selector to prevent the sneak current for RRAM devices, which is deeply associated with rectification effect. In the present paper, it was found that the devices exhibited rectification phenomenon at HRS while quasi-ohmic I–V characteristics was observed for LRS due to the conducting filaments between TiN and Au electrodes. It was believed that the rectification at HRS originated from the Schottky barrier across SiO2-VO/SiO2 interface, which was verified by density functional theory calculations. Moreover, different annealing processes of TiN/SiO2 films were proposed to simulate the status of O2− during the resistive switching process. This proved the absorption and extraction of O2− on the TiN electrode. The rectification behavior achieved by oxygen vacancy modulated interface engineering may offer a method for large scale integrated RRAM circuits with good reliability.