Layer-by-layer growth of complex-shaped three-dimensional nanostructures with focused electron beams

TL;DR

This paper introduces a novel layer-by-layer 3D nanofabrication method using focused electron beams, enabling complex-shaped nanostructures with high precision and correction for various effects during deposition.

Contribution

It extends FEBID to 3D nanostructure growth by integrating layer-by-layer printing with proximity effect correction, allowing fabrication of complex 3D nanoscale objects from STL files.

Findings

Successfully fabricated free-standing nanowires and curved surfaces

Demonstrated 3D printing from standard STL files

Adjusted for beam heating, defocusing, and gas flux effects

Abstract

The fabrication of three-dimensional (3D) nanostructures is of great interest to many areas of nanotechnology currently challenged by fundamental limitations of conventional lithography. One of the most promising direct-write methods for 3D nanofabrication is focused electron beam-induced deposition (FEBID), owing to its high spatial resolution and versatility. Here we extend FEBID to the growth of complex-shaped 3D nanostructures by combining the layer-by-layer approach of conventional macroscopic 3D printers and the proximity effect correction of electron beam lithography. This framework is based on the continuum FEBID model and is capable of adjusting for a wide range of effects present during deposition, including beam-induced heating, defocussing and gas flux anisotropies. We demonstrate the capabilities of our platform by fabricating free-standing nanowires, surfaces with varying curvatures and topologies, and general 3D objects, directly from standard stereolithography (STL) files and using different precursors. Real 3D nanoprinting as demonstrated here opens up exciting avenues for the study and exploitation of 3D nanoscale phenomena.