Focused electron beam induced processing (FEBIP) comprising FEBID (deposition) and FEBIE (etching) is a direct write or etch, single step technique for high resolution nano-patterning. The whole process takes place inside a single tool, the scanning electron microscope (SEM). A focused electron beam hits the sample in the presence of a precursor gas which contains the element to be deposited. The precursor molecules adsorb to the surface of the substrate. The adsorbed precursor molecules are dissociated with a certain probability (given by the dissociation cross section) by the primary, secondary and back scattered electrons into a deposited fragment and volatile byproducts. FEBID provides great potential for 3D nano-printing due to its flexibility and the absence of resists and subsequent processing steps. The work described in this thesis was part of a Marie Skłodowska-Curie Training Network on ‘Low energy ELEctron driven chemistry for the advantage of emerging NAno-fabrication methods’ (ELENA). In particular, three challenges to the FEBID process were addressed to achieve control over the process for nanofabrication, i) the purity of the deposits, ii) the speed of the process and iii) control over the 3D-shape of deposits....@en

Seven gold(I) N-heterocyclic carbene (NHC) complexes were synthesized, characterized, and identified as suitable precursors for focused electron beam-induced deposition (FEBID). Several variations on the core Au(NHC)X moiety were introduced, that is, variations of the NHC ring (imidazole or triazole), of the alkyl N-substituents (Me, Et, or iPr), and of the ancillary ligand X (Cl, Br, I, or CF₃). The seven complexes were tested as FEBID precursors in an on-substrate custom setup. The effect of the substitutions on deposit composition and growth rate indicates that the most suitable organic ligand for the gold precursor is triazole-based, with the best deposit composition of 15 atom % gold, while the most suitable anionic ligand is the trifluoromethyl group, leading to a growth rate of 1 × 10⁻² nm³/e⁻.

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Two platinum precursors, Pt(CO)₂Cl₂ and Pt(CO)₂Br₂, were designed for focused electron beam-induced deposition (FEBID) with the aim of producing platinum deposits of higher purity than those deposited from commercially available precursors. In this work, we present the first deposition experiments in a scanning electron microscope (SEM), wherein series of pillars were successfully grown from both precursors. The growth of the pillars was studied as a function of the electron dose and compared to deposits grown from the commercially available precursor MeCpPtMe₃. The composition of the deposits was determined using energy-dispersive X-ray spectroscopy (EDX) and compared to the composition of deposits from MeCpPtMe₃, as well as deposits made in an ultrahigh-vacuum (UHV) environment. A slight increase in metal content and a higher growth rate are achieved in the SEM for deposits from Pt(CO)₂Cl₂ compared to MeCpPtMe3. However, deposits made from Pt(CO)₂Br₂ show slightly less metal content and a lower growth rate compared to MeCpPtMe₃. With both Pt(CO)₂Cl₂ and Pt(CO)₂Br₂, a marked difference in composition was found between deposits made in the SEM and deposits made in UHV. In addition to Pt, the UHV deposits contained halogen species and little or no carbon, while the SEM deposits contained only small amounts of halogen species but high carbon content. Results from this study highlight the effect that deposition conditions can have on the composition of deposits created by FEBID.

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