Efficient NH3-based process to remove chlorine from electron beam deposited ruthenium produced from (\u03b73-C3H5)Ru(CO)3Cl

Markus Rohdenburg,Christopher R Brewer,Petra Swiderek,Hannah Boeckers,Lisa Mcelwee-White

doi:10.1038/s41598-020-67803-y

Markus Rohdenburg, Christopher R Brewer + Show 3 more

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https://doi.org/10.1038/s41598-020-67803-y

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Journal: Scientific Reports	Publication Date: Jul 2, 2020
Citations: 18	License type: open-access

Affiliation: University of Bremen, University of Florida

Abstract

The fabrication of Ru nanostructures by focused electron beam induced deposition (FEBID) requires suitable precursor molecules and processes to obtain the pure metal. So far this is problematic because established organometallic Ru precursors contain large organic ligands, such as cyclopentadienyl anions, that tend to become embedded in the deposit during the FEBID process. Recently, (η3-C3H5)Ru(CO)3X (X = Cl, Br) has been proposed as an alternative precursor because CO can easily desorb under electron exposure. However, allyl and Cl ligands remain behind after electron irradiation and the removal of the halide requires extensive electron exposures. Auger electron spectroscopy is applied to demonstrate a postdeposition purification process in which NH3 is used as a reactant that enhances the removal of Cl from deposits formed by electron irradiation of thin condensed layers of (η3-C3H5)Ru(CO)3Cl. The loss of CO from the precursor during electron-induced decomposition enables a reaction between NH3 and the Cl ligands that produces HCl. The combined use of electron-stimulated desorption experiments and thermal desorption spectrometry further reveals that thermal reactions contribute to the loss of CO in the FEBID process but remove only minor amounts of the allyl and Cl ligands.

Highlights

The fabrication of Ru nanostructures by focused electron beam induced deposition (FEBID) requires suitable precursor molecules and processes to obtain the pure metal
By overlaying both mass spectra weighted by suitable factors, the mass spectrum observed during electron-stimulated desorption (ESD) is roughly reproduced (Supplementary Information, Fig. S1), suggesting that H transfer occurs as a minor reaction channel
In the set of experiments aiming at the deposit purification process, we investigated the efficiency of NH3 with respect to removal of Cl from a deposit prepared from (η3-C3H5)Ru(CO)3Cl by the sequence of ESD and Thermal desorption spectrometry (TDS) experiments described above

Summary

Introduction

The fabrication of Ru nanostructures by focused electron beam induced deposition (FEBID) requires suitable precursor molecules and processes to obtain the pure metal. This is problematic because established organometallic Ru precursors contain large organic ligands, such as cyclopentadienyl anions, that tend to become embedded in the deposit during the FEBID process. Carbon-rich deposits produced from trimethyl(methylcyclopentadienyl)platinum(IV) (MeCpPtMe3) were converted to pure Pt by post-deposition electron irradiation in the presence of H2O8 As another example, a FEBID process that simultaneously dosed dimethyl(acetylacetonato)gold(III) (AuMe2(acac)) and H 2O yielded a deposit with Au content above 80%, in contrast to low-purity deposits produced from AuMe2(acac) alone[9]. Extensive electron irradiation is required to remove the halide ligand[14]

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