This article investigates the resistance switching behaviors of a device with a Pt/Cu/SiON/TiN/SiO2/Si structure. By inserting a Cu ultrathin film between the SiON layer and the Pt top electrode, the device exhibits bipolar resistive switching characteristics after a forming process at 13.6 V. However, the forming and resistive switching process cannot be observed in the device if the Cu thin film is omitted. Additionally, we employ a two-step forming process to reduce the forming voltage to 7.5 V. The proposed device also demonstrates stable resistance states during 105 cycling bias pulse operations and acceptable retention characteristics after an endurance test at 85 C. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3518701] All rights reserved.