Temperature Distribution in TaOX Resistive Switching Devices Assessed In Operando by Scanning Thermal Microscopy

Understanding the physical changes during electroformation and switching processes in transition-metal-oxide-based non-volatile memory devices is important for advancing this technology. Relatively few characteristics of these devices have been assessed in operando. In this work, we present scanning thermal microscopy measurements in vacuum on TaOx-based memory devices electro-formed in both positive and negative polarities and high-and low-resistance states. The observed surface temperature footprints of the filament showed higher peak temperatures and narrower temperature distributions when the top electrode served as the anode in the electroformation process. This is consistent with a model in which a hot spot is created by a gap in the conducting filament that forms closest to the anode. A similar behavior was seen on comparing the high-resistance state to the low-resistance state, with the low-resistance footprint showing a lower peak and a larger width, consistent with the gap disappearing when the device is switched from high resistance to low resistance.

Automated summary

Understanding the physical changes during electroformation and switching processes in transition-metal-oxide-based non-volatile memory devices is important for advancing this technology. In this study, scanning thermal microscopy measurements were conducted in vacuum on TaOx-based memory devices to assess the characteristics of these devices. The results showed that a hot spot is created by a gap in the conducting filament that forms closest to the anode during the electroformation process. Additionally, the gap disappears when the device is switched from high resistance to low resistance.