title: Formation of pure Cu nanocrystals upon post-growth annealing of Cu-C material obtained from focused electron beam induced deposition: comparison of different methods.
abstract: In this paper we study in detail the post-growth annealing of a copper-containing material deposited with focused electron beam induced deposition (FEBID). The organometallic precursor Cu(II)(hfac)2 was used for deposition and the results were compared to that of compared to earlier experiments with (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB). Transmission electron microscopy revealed the deposition of amorphous material from Cu(II)(hfac)2. In contrast, as-deposited material from (hfac)Cu(I)(VTMS) and (hfac)Cu(I)(DMB) was nano-composite with Cu nanocrystals dispersed in a carbonaceous matrix. After annealing at around 150-200 °C all deposits showed the formation of pure Cu nanocrystals at the outer surface of the initial deposit due to the migration of Cu atoms from the carbonaceous matrix containing the elements carbon, oxygen, and fluorine. Post-irradiation of deposits with 200 keV electrons in a transmission electron microscope favored the formation of Cu nanocrystals within the carbonaceous matrix of freestanding rods and suppressed the formation on their surface. Electrical four-point measurements on FEBID lines from Cu(hfac)2 showed five orders of magnitude improvement in conductivity when being annealed conventionally and by laser-induced heating in the scanning electron microscope chamber.
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, 3602 Thun, Switzerland ; AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Szkudlarek
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, 3602 Thun, Switzerland ; Center for Semiconductor Components, State University of Campinas, 13083-870, Campinas, SP, Brazil.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Rodrigues Vaz
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Electron Microscopy Center, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
authors.forename: Andrzej
authors.initials: A
authors.lastname: Rudkowski
authors.affiliation: AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, al. A. Mickiewicza 30, 30-059 Krakow, Poland.
authors.forename: Czesław
authors.initials: C
authors.lastname: Kapusta
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Electron Microscopy Center, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
authors.forename: Rolf
authors.initials: R
authors.lastname: Erni
authors.affiliation: Center for Semiconductor Components, State University of Campinas, 13083-870, Campinas, SP, Brazil.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Moshkalev
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, 3602 Thun, Switzerland.
authors.forename: Ivo
authors.initials: I
authors.lastname: Utke
keywords: Cu nanocrystals; Cu(hfac)2; focused electron beam induced deposition (FEBID); post-growth annealing of Cu–C material