A progressive wafer scale approach for Sub-10 nm nanogap structures.

Sub-10 nm nanostructures with high precision and uniformity are of significant interest due to their unique quantum properties and critical role in next-generation devices. However, current fabrication techniques are often constrained by the slow, small-area processes of electron beam lithography or the high costs of extreme ultraviolet (EUV) lithography, limiting broader accessibility. To address these challenges, we have advanced the atomic layer lithography method into an efficient, scalable approach for fabricating sub-10 nm nanogaps with high uniformity across entire wafer areas. The key strategy of this method is the direct employment of photoresist patterns as both protective and sacrificial layers, streamlining the process. Comprehensive optical and electron microscopy analyses, supported by COMSOL simulations and terahertz transmission measurements, confirm the formation of highly uniform, high-quality nanogaps across the entire wafer. Compared to the original atomic layer lithography, our approach offers enhanced patterning flexibility, including a simplified process, improved compatibility with a wide range of metals, and the ability to perform additional patterning on initial nanogap structures. This scalable technique, compatible with standard lithographic tools, provides a promising pathway for sub-10 nm nanogap fabrication, with strong potential for both academic research and industrial applications.