Abstract
High-resolution metallic nanostructures can be fabricated with multistep processes, such as electron beam lithography or ice lithography. The gas-assisted direct-write technique known as focused electron beam induced deposition (FEBID) is more versatile than the other candidates. However, it suffers from low throughput. This work presents the combined approach of FEBID and the above-mentioned lithography techniques: direct electron beam lithography (D-EBL). A low-volatility copper precursor is locally condensed onto a room temperature substrate and acts as a positive tone resist. A focused electron beam then directly irradiates the desired patterns, leading to local molecule dissociation. By rinsing or sublimation, the non-irradiated precursor is removed, leaving copper-containing structures. Deposits were formed with drastically enhanced growth rates than FEBID, and their composition was found to be comparable to gas-assisted FEBID structures. The influence of electron scattering within the substrate as well as implementing a post-purification protocol were studied. The latter led to the agglomeration of high-purity copper crystals. We present this as a new approach to electron beam-induced fabrication of metallic nanostructures without the need for cryogenic or hot substrates. D-EBL promises fast and easy fabrication results.
Highlights
Our work presents the first report of direct-write electron beam lithography (D-Electron-beam lithography (EBL)) in a positive low-volatility copper precursor resist
“Cryo-focused electron beam induced deposition (FEBID)” is a suitable technique for the deposition of metal-containing structures from metal–organic precursors that are volatile at room temperature
The compound is a powder, stable at room temperature and evaporates only at elevated temperatures repeated in four different regions of the condensate to obtain irradiation at four different resist thicknesses (Figure 1c)
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. The fabrication of high-resolution metal structures in the micro- and nanometer scale is of great interest for both industry and research. Electron-beam lithography (EBL) is an exposure technique for fabricating micro- and nanostructures on an industrial scale. It is mainly used to manufacture 2D nanostructures with sub 200 nm feature sizes but can reach the sub-10 nm range [1]. EBL is a multistep process consisting of the deposition and irradiation of a resist, the removal of the (non)exposed parts, the deposition of a metal layer and the final lift-off process leaving the intended structure on the substrate
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
