High-Precision 3D-Nanoprinting for Sheet-like Structures via FEBID

Among the few additive-manufacturing techniques capable of creating 3-dimensionalobjects on the nanoscale, 3D nanoprinting via Focused Electron Beam Induced Deposition(3D-FEBID) is an increasingly relevant technology for building high-fidelity nanostructures.Its capabilities of depositing feature sizes below 20 nm under optimized conditions andbelow 100 nm on a regular basis and its flexibility both in terms of substrate as well asprecursor materials make it a unique technology with many possibilities and yet unexploredapplications. While it has been used and developed further for a few years now, mostfabricated structures in the past have been meshed [1], meaning a combination of differentlyoriented, individual nanowires, connected at specific points in 3D space according to thetarget application. This work leverages 3D-FEBID to the next level by expanding itscapabilities from mesh-like towards closed (sheet-like) structures with a high degree ofprecision. The main challenge and source of most deviations from target shapes is therebybased on local beam heating and its implications on local growth rates. While wellunderstoodin meshed structures, closed objects revealed additional dependencies on thedimensions of built objects and the XY pixel position within the structures. Furthermore,electron trajectories are more complex in closed objects, introducing additional proximityeffects. To address these problems, we combined finite-difference simulations with 3DFEBIDexperiments and developed a Python-based compensation tool, capable of stabilizingthe growth for each XY pixel point in individual patterning planes by pre-determinedparameter adjustments (Fig. 1a). The gained insight allowed further expansion, now beingapplicable for different element widths and -heights, as demonstrated by more advancedstructures (Fig. 1b). In a last step we introduced trapezoid and inclined elements into ourcompensation code (Fig. 2a), which we then combined to a “construction kit” tool that isable to build compound structures (Fig. 2b-d). By that, we crucially expanded FEBID-based3D nanoprinting by opening up design possibilities for closed and consequently mixedobjects for novel applications in various fields of research and development.