Thermal dependence of the current in TiN/Ti/HfO2/W memristors at different intermediate conduction states

The dependence of the current in TiN/Ti/HfO2/W devices on the temperature is investigated in the range from 78 K to 340 K. Resistive switching cycles at 78 K are conducted to explore the thermal dependence in filament configurations with different intermediate resistance states. The less conductive states show an increase of the current as the temperature rises, while the fully formed filament displays a metallic-like behavior. A comprehensive model, based on the Stanford Model including a series resistance, is proposed and successfully validated by experimental data. The interplay between the ohmic and non-linear components in the model for different filament states is analyzed, emphasizing the dominance of the non-linear component (and its corresponding thermal dependence) in partially formed filaments and the prevalence of the ohmic component in the fully formed filament, which shows a decreasing current as the temperature rises. A complete compact model for simulation of circuits including the thermal dependence of these devices is developed.