Anodic oxidation effects at the copper/silicon oxide interface

We report on anodic oxidation effects in memristively switching Cu/SiO2/Pt and Cu/CuOx/SiO2/Pt Electrochemical Metallization Cells. In-depth x-ray photoelectron spectroscopy reveals the formation of a Cu-ion reservoir composed of Cu(OH)2 underneath the anode during oxidation. By using cyclic voltammetry partial redox reactions are observed both in SiO2- and CuOx/SiO2-based devices. From our analysis we conclude that the CuOx layer acts as a reservoir for Cu-ions, similar to the low work-function electrode in valance change mechanism devices, which acts a reservoir for oxygen vacancies. Integration of a CuOx layer may thus allow to tailor the resistive switching performance of cation based memristors.