Characterization of Graphene and Indium Tin Oxynitride Thin Films for Use as Layers in Resistive Memories

Graphene is a two‐dimensional material, comprising sp²‐hybridized carbon atoms organized in a hexagonal lattice. An application of this material lies in resistive random‐access memories (ReRAMs). In this work, resistive memory devices with three layers were manufactured. Graphene thin films were deposited by dip coating on indium tin oxynitride (ITON) electrodes. For the ITON contacts, indium tin oxide was evaporated in an oxygen atmosphere and subsequently annealed with a nitrogen flow atmosphere in a conventional furnace at different temperatures: 350, 400, 500 and 550 °C. The evaporation technique was employed to produce aluminum as top contacts. For graphene and ITON characterization, structural analysis of Raman, electrical measurements through Hall effect and optical UV – Vis measurements were performed. Resistive memories were also characterized through I × V analysis. The devices can be characterized as unipolar, with threshold switching attributed to the formation of oxygen vacancies. ITON was deposited with a substantial layer, containing oxygen, while graphene, with an average thickness of 30 nm measured by profilometer, forms a thinner layer. During the voltage increase and subsequent decrease, it is postulated that the oxygen vacancies within this material may migrate towards the intermediate layer, graphene, due to its reduced thickness and defects.