Adding the Design Possibility of Variable Diameters via Blurred Electron Beams during 3D Nanoprinting via FEBID

Description

Additive, direct-write fabrication via focused particle beams has evolved into a reliable 3D printing technology at the micro and nanoscale[1]. Similar to focused ion beam induced deposition (FIBID), the electron-based equivalent FEBID uses the nanoscale particle beam for highly localized immobilization of surface adsorbed precursor molecules. As the latter is injected by gas injection system, the demands on substrate material (vacuum and e-beam compatible) and surface morphology (accessible by the e-beam) are modest. Accurate control of the lateral beam movement enables highly localized deposition and thereby allows the fabrication of even complex 3D structures with nanoscale features down to the sub-20 nm range for freestanding features. While indispensable for certain purposes (e.g. 3D magnetic lattices[2] or nano-plasmonics [3]), the morphological delicacy of such structures can also result in low mechanical rigidity and limited thermal / electrical conductivities, narrowing the range of possible applications. Furthermore, it has recently been shown, that the overall 3D design is partly implying the finally arising branch diameters in an invariable way[4], which can limit the final functionality. Hence, it follows that a controlled diameter tunability is less optional but rather a prerequisite. Based on this motivation, we here introduce deliberate beam blurring as additional fabrication parameter and study its implications on 3D structures (Fig. 1). In addition, we observe and explain an increase in growth efficiencies by factors up to 5, driven by a shift in working regime conditions (Fig. 2a). At the same time, the highly unwanted proximal growth beneath intended 3D branches is strongly delayed, which increases the reliability of 3D-FEBID. By that, controlled on-purpose beam blurring expands the design flexibility of this technology (Fig. 2b) by means of tunable diameters for meshed objects at higher volume growth rates and reduced proximal growth.
[1] Winkler et al, J. Appl. Phys. 125 (2019) 210901
[2] Keller et al, Sci. Rep. 8 (2018) 6160
[3] Winkler et al, ACS Appl. Mater. Interfaces 9 (2017) 8233-8240
[4] Winkler et al, Addit. Manuf. 46 (2021) 102076

Period	27 Sept 2021 → 30 Sept 2021
Event title	European Focused Ion Beam workshop and combined Fit4Nano Cost action meeting: EUFN 2021/Fit4Nano User meeting
Event type	Workshop
Location	Wien, AustriaShow on map
Degree of Recognition	International