Reproducible resistive-switching behavior in copper-nitride thin film prepared by plasma-immersion ion implantation

Copper nitride film prepared by plasma-immersion ion implantation (PIII) is demonstrated to exhibit reversible resistance variance character. By forming a gradually distributed nitrogen concentration in the Cu-nitride film, the nitride-based memory devices show bipolar nature with a low operation voltage, forming-free characteristics and a distinguishable resistance ratio. The bipolar switching behavior is attributed to the formation and rupture of conductive filaments within a cycle, which is confirmed by spreading-resistance images of a conducting atomic force microscope. Based on X-ray photoelectron spectroscopy (XPS) analysis, semiconducting Cu3N phase and metallic Cu4N phase coexist in the copper nitride film and local conducting filaments might be formed by interconnection of the metallic phases by migration of Cu+ ions under a bias voltage. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim