Plasma-Based Post-Growth Purification for Metal FEBID Nanoprinting

Focused electron beam induced deposition (FEBID) is an emerging direct-write nanofabrication technique enabling the additive manufacturing of complex nanoarchitectures with applications in nanoelectronics, nanomagnetism, and spintronic devices[1]. However, carbonaceous originating from organometallic precursors significantly reduces the metallic purity and functional performance of deposited the printed nanostructures. In this work, we demonstrate a plasma-based post-growth purification strategy for FEBID nanostructures achieving high structural fidelity with feature sizes down to ~60 nm. Following deposition, reactive plasma treatment was applied using an O₂/Ar mixture to selectively remove carbon-rich shell and enhance the metallic composition of the printed structures. Electron energy loss spectroscopy (EELS) for studied as-deposited structures revealed a metal-rich core surrounded by a big carbonaceous shell. After plasma purification the carbon shell was substantially reduced, increasing the metal purity overall from 10% to ~ 80% at printed complex structures, while maintaining the integrity. This combined approach of high-fidelity FEBID growth assisted by modelling [2], followed by plasma-based purification step provides a scalable pathway toward high-purity functional metallic nanostructures for next-generation nanomanufacturing and advanced device applications. References: [1] Reisecker V, Winkler R and Plank H 2024 A Review on Direct-Write Nanoprinting of Functional 3D Structures with Focused Electron Beams Adv. Funct. Mater. 34 2407567 [2] Okasha S and Almeida T P 2025 The Role of Dwell Time on Advancing 3D Nano-printing of Complex Iron Nanostructure Geometries using Focused Electron Beam Induced Deposition Microscopy and Microanalysis (2025) 31