High-quality Nano-patterning of Oxide Interfaces Using Sacrificial Metal Electrode Masks

Complex oxide interfaces, such as SrTiO₃ and KTaO₃ based heterostructures, have attracted significant interest due to their intriguing physical properties and potential for advanced device applications. However, these interfaces are highly sensitive to contamination and prone to oxygen vacancy formation during ion irradiation, significantly degrading device performance. Attempts to use insulating layers as masks, low-temperature ion beam irradiation, and shadow masks have failed to completely preserve pristine sample quality or achieve nanoscale device dimensions.

Here, we present a novel method for patterning oxide interfaces by employing sacrificial metal electrodes as masks in conjunction with reactive ion etching, enabling the fabrication of sub-micron-sized devices. Our approach mitigates the common contamination issues associated with previous methods, providing a clean and controlled process for nanoscale device fabrication. Our results demonstrate that the patterned interfaces retain their high quality, including carrier mobilities, with no measurable degradation compared to unpatterned samples.