In this work, we investigated the effect of growth temperature and doping of Nb, with a valence different from that of Ni, on the resistance switching behavior of NiOx films. Reactive dc magnetron sputtering was used to fabricate Pt/NiOx/Pt metal-insulator-metal (MIM) stacks on Ti/SiO2/Si substrates with Nb doping at various substrate temperatures. The crystallinity, surface morphology, and chemical bonding states of NiOx were also characterized in conjunction with the resistance switching. Deposition at 400 degrees C improved the resistance switching endurance, and Nb doping of up to 3.5% at 400 degrees C produced a higher endurance for the SET/RESET processes with a narrower distribution of V-SET as compared to the undoped NiOx films. X-ray diffraction showed that sputtering at 400 degrees C made the (111) textures pronounced with the reduced full width at half-maximum of the (111) peak as compared to the NiOx films deposited at room temperature. X-ray photoemission spectroscopy showed that the Nb doping of NiOx films produced a higher density in the metallic Ni-0 than in the undoped NiOx films deposited at the same temperature. This work shows that resistive switching behavior of NiOx can be enhanced by doping it with Nb of different oxidation valences. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3231487]