Dry-Patterning Chemically Sensitive Quantum Materials Using a Computer Numerical Control Router Machine

Accurately and consistently patterning quantum materials for electrical transport measurements is crucial for the field of quantum device manufacturing. Nevertheless, the most used technique, photolithography, poses a risk of degrading or even damaging chemically sensitive quantum materials during the fabrication process. In this work, we developed a dry-patterning approach for device fabrication, achieving lateral etching resolution as fine as 5 µm. The method harnesses the capabilities of a desktop computer numerical control (CNC) router machine to etch patterns into thin films, leaving behind the desired devices on the substrate. Using this technique, we have successfully produced Hall bars with conductive channel widths of less than 60 µm on films of superconducting single-layer FeSe/SrTiO₃ capped with approximately 20 layers of FeTe. Transport measurements have demonstrated a superconducting zero-resistance temperature of 9.6 K across several device geometries, including a sample-wide Van der Pauw (vdP). However, the highest onset temperature (T_onset) of 23.2 K is exhibited in the vdP configuration and gradually decreases as the Hall bar dimensions decrease, reaching 12.2 K for the smallest device produced. Our approach offers a time-efficient, cost-effective, and chemical-free strategy to fabricate devices for understanding heterogeneous quantum phenomena in quantum materials.