Direct electron beam writing of silver using a $\beta$-diketonate precursor: first insights

TL;DR

This study introduces a novel use of a silver $eta$-diketonate precursor in focused electron beam induced deposition (FEBID), demonstrating the ability to create 3D silver structures with unique layered morphologies, despite low silver content.

Contribution

First application of a silver $eta$-diketonate precursor in FEBID, showing its compatibility with standard equipment and revealing deposit composition and morphology characteristics.

Findings

Successful deposition of silver structures using the precursor.

Deposits exhibit layered structures with low silver content.

Surface silver particles observed post-deposition.

Abstract

Direct electron beam writing is a powerful tool for fabricating complex nanostructures in a single step. The electron beam locally cleaves the molecules of an adsorbed gaseous precursor to form a deposit, similar to 3D printing but without the need for a resist or development step. Here, we employ for the first time a silver $\beta$-diketonate precursor for focused electron beam induced deposition (FEBID). The used compound (hfac)AgPMe$_3$ operates at an evaporation temperature of 70 - 80{\deg}C and is compatible with commercially available gas injection systems used in any standard scanning electron microscope. Growth of smooth 3D geometries could be demonstrated for tightly focused electron beams, albeit with low silver contents in the deposit volume. The electron beam induced deposition proved sensitive to the irradiation conditions leading to varying compositions of the deposit and internal inhomogeneities such as the formation of a layered structure consisting of a pure silver layer at the interface to the substrate covered by a deposit layer with low silver content. Imaging after the deposition process revealed morphological changes such as the growth of silver particles on the surface. While these effects complicate the application for 3D printing, the unique deposit structure with a thin, compact silver film beneath the deposit body is interesting from a fundamental point of view and may offer additional opportunities for applications.