Response under low-energy electron irradiation of a thin film of a potential copper precursor for focused electron beam induced deposition (FEBID)

Abstract

Background: Focused electron beam induced deposition (FEBID) allows for the deposition of free standing material within nanometre sizes. The improvement of the technique needs a combination of new precursors and optimized irradiation strategies to achieve a controlled fragmentation of the precursor for leaving deposited material of desired composition. Here a new class of copper precursors is studied following an approach that probes some surface processes involved in the fragmentation of precursors. We use complexes of copper(II) with amines and perfluorinated carboxylate ligands that are solid and stable under ambient conditions. They are directly deposited on the surface for studying the fragmentation with surface science tools. Results: Infrared spectroscopy and high-resolution electron energy loss spectroscopy (HREELS) are combined to show that the precursor is able to spontaneously lose amine ligands under vacuum. This loss can be enhanced by mild heating. The combination of mass spectrometry and low-energy electron irradiation (0–15 eV) shows that full amine ligands can be released upon irradiation, and that fragmentation of the perfluorinated ligands is induced by electrons of energy as low as 1.5 eV. Finally, the cross section for this process is estimated from the temporal evolution in the experiments on electron-stimulated desorption (ESD). Conclusion: The release of full ligands under high vacuum and by electron irradiation, and the cross section measured here for ligands fragmentation allow one to envisage the use of the two precursors for FEBID studies.

Copper(II) Perfluorinated Carboxylate Complexes with Small Aliphatic Amines as Universal Precursors for Nanomaterial Fabrication

“…2 [Cu(µ-O 2 CR f ) 2 ] + 2 RNCO + 2H 2 O → [Cu 2 (RNH 2 ) 2 (µ-O 2 CR f ) 4 ] + 2CO 2 is analogous to those we reported copper compounds containing tert-butylamine [ 9 ], as well as ethylamine [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] ( 2 ) and [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] ( 3 ) complexes [ 11 , 12 ].…”

“…The synthesis of compounds [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 2 F 5 ) 4 ] ( 2 ) and [Cu 2 (EtNH 2 ) 2 (µ-O 2 CC 3 F 7 ) 4 ] ( 3 ) has been described by us earlier [ 11 , 12 ]. The complexes ( 2 ) and ( 3 ) were prepared and tested for interactions with low-energy electrons.…”

“…As a result, compounds with the formulas: [Cu 2 ( t BuNH 2 ) 2 (μ-O 2 CC 2 F 5 ) 4 ], [Cu 2 ( s BuNH 2 ) 2 (μ-O 2 CC 2 F 5 ) 4 ], [Cu 2 (EtNH 2 ) 2 (μ-O 2 CC 2 F 5 ) 4 ], and [Cu 2 (EtNH 2 ) 2 (μ-O 2 CC 3 F 7 ) 4 ] were synthesized and tested for interactions with low-energy electrons and a possible use in the focused electron beam induced deposition (FEBID) method. Due to their gel form, compounds could be directly deposited on a surface which allowed the studying them with surface science tools in a vacuum environment [ 11 , 12 ].…”

Electron-induced fragmentation mechanisms in organic monomers and their implications for photoresist optimization for EUV lithography

“…Complete information on the tool can be found elsewhere. 16,21,22 The Please do not adjust margins Please do not adjust margins typical background pressure in the UHV chamber was maintained at around 5 X 10 -10 mbar with the sample introduced at a gas pressure in the range of (2-7) X 10 -9 mbar.…”

“…Electron stimulated desorption (ESD) experiments were carried out by exposing the ultrathin film of MIB to LEEs of 1-20 eV and monitoring the energy dependence of the electron-induced desorption of individual species with the RGA as described in detail elsewhere. 22 The steps to obtain electron-stimulated yields from the raw spectra are shown in figure S1 of the supplementary information.…”