Enabling Ion Milling Redeposition Nano-Templates for Scalable Nanofabrication of Chemical-Sensing Metamaterials with 10 nm-Feature Size

Achieving low-cost patterning of 10 nm-scale nanostructures remains a critical challenge in nanofabrication. Conventional electron beam lithography has a prolonged processing time and limited throughput due to its intrinsic small-area processing nature. Extreme ultraviolet (EUV) lithography faces prohibitive costs in equipment and materials. While industrial nanoimprinting offers a lower-cost, high-throughput alternative, its resolution is fundamentally constrained by the template's minimum feature size. Herein, we present a new nanofabrication process that exploits the redeposition effect in ion milling to fabricate controllable 10 nm-scale nanogaps. This approach enabled the preparation of gratings and nanorings array integrated with noble metal nanogaps for applications in surface-enhanced Raman spectroscopy (SERS). Furthermore, gratings and nanopillar arrays with sidewalls coated by a metal mask were dry-etched to form a self-aligned stacked nanomorphology on a silicon substrate without optical alignment, inheriting the metal mask's minimum feature size. The resulting high-quality templates subsequently facilitated high-fidelity replication of diminutive structures via nanoimprint lithography (NIL). This scalable strategy holds significant potential as a feasible route for manufacturing applications in nanophononics, biosensing, quantum devices, integrated circuits (ICs), and beyond.