Effect of ITO electrode with different oxygen contents on the electrical characteristics of HfOx RRAM devices

In this study, the influence of indium tin oxide (ITO) top electrodes with different oxygen contents on the resistive switching characteristics of HfOx/TiN capacitor structure is investigated. Switching parameters, including set and reset voltage values, and high and low resistance values are highly related to the properties of ITO thin films. Higher resistance values in both states can be obtained when ITO thin films with higher oxygen contents are used as top electrodes; such values are accompanied by larger set voltages and fluctuating transient currents during the reset process. Based on the proposed filament model, we suggest that the switching mechanism of HfOx/TiN structure is attributed to the formation and rupture of conducting filamentary paths near the anodic side, which is highly correlated with the properties of the top electrode. The top electrode must be well determined to obtain reliable switching properties.