title: Annealing-Based Electrical Tuning of Cobalt-Carbon Deposits Grown by Focused-Electron-Beam-Induced Deposition.
abstract: An effective postgrowth electrical tuning, via an oxygen releasing method, to enhance the content of non-noble metals in deposits directly written with gas-assisted focused-electron-beam-induced deposition (FEBID) is presented. It represents a novel and reproducible method for improving the electrical transport properties of Co-C deposits. The metal content and electrical properties of Co-C-O nanodeposits obtained by electron-induced dissociation of volatile Co2(CO)8precursor adsorbate molecules were reproducibly tuned by applying postgrowth annealing processes at 100 °C, 200 °C, and 300 °C under high-vacuum for 10 min. Advanced thin film EDX analysis showed that during the annealing process predominantly oxygen is released from the Co-C-O deposits, yielding an atomic ratio of Co:C:O = 100:16:1 (85:14:1) with respect to the atomic composition of as-written Co:C:O = 100:21:28 (67:14:19). In-depth Raman analysis suggests that the amorphous carbon contained in the as-written deposit turns into graphite nanocrystals with size of about 22.4 nm with annealing temperature. Remarkably, these microstructural changes allow for tuning of the electrical resistivity of the deposits over 3 orders of magnitude from 26 mΩ cm down to 26 μΩ cm, achieving a residual resistivity of ρ2K/ρ300 K= 0.56, close to the value of 0.53 for pure Co films with similar dimensions, making it especially interesting and advantageous over the numerous works already published for applications such as advanced scanning-probe systems, magnetic memory, storage, and ferroelectric tunnel junction memristors, as the graphitic matrix protects the cobalt from being oxidized under an ambient atmosphere.
authors.affiliation: Laboratory for Mechanics of Materials and Nanostructures, Swiss Federal Laboratories for Materials Science and Technology (EMPA) , Feuerwerkstrasse 39, 3602 Thun, Switzerland.|Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas , Rua Sérgio Buarque de Holanda 777, Cidade Universitária, 13083-859 Campinas-SP, Brazil.|Faculdade de Engenharia Elétrica e Computação e Centro de Componentes Semicondutores, Universidade Estadual de Campinas , Avenida Albert Einstein 400, 13083-852 Campinas-SP, Brazil.
authors.forename: Marcos V
authors.initials: MV
authors.lastname: Puydinger Dos Santos
authors.affiliation: Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas , Rua Sérgio Buarque de Holanda 777, Cidade Universitária, 13083-859 Campinas-SP, Brazil.
authors.forename: Murilo F
authors.initials: MF
authors.lastname: Velo
authors.affiliation: Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas , Rua Sérgio Buarque de Holanda 777, Cidade Universitária, 13083-859 Campinas-SP, Brazil.
authors.forename: Renan D
authors.initials: RD
authors.lastname: Domingos
authors.affiliation: Electron Microscopy Center, Swiss Federal Laboratories for Materials Science and Technology (EMPA) , Überlandstrasse 129, 8600 Dübendorf, Switzerland.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Laboratory for Mechanics of Materials and Nanostructures, Swiss Federal Laboratories for Materials Science and Technology (EMPA) , Feuerwerkstrasse 39, 3602 Thun, Switzerland.
authors.forename: Xavier
authors.initials: X
authors.lastname: Maeder
authors.affiliation: Laboratory for Mechanics of Materials and Nanostructures, Swiss Federal Laboratories for Materials Science and Technology (EMPA) , Feuerwerkstrasse 39, 3602 Thun, Switzerland.
authors.forename: Carlos
authors.initials: C
authors.lastname: Guerra-Nuñez
authors.affiliation: Laboratory for Mechanics of Materials and Nanostructures, Swiss Federal Laboratories for Materials Science and Technology (EMPA) , Feuerwerkstrasse 39, 3602 Thun, Switzerland.
authors.forename: James P
authors.initials: JP
authors.lastname: Best
authors.affiliation: Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas , Rua Sérgio Buarque de Holanda 777, Cidade Universitária, 13083-859 Campinas-SP, Brazil.
authors.forename: Fanny
authors.initials: F
authors.lastname: Béron
authors.affiliation: Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas , Rua Sérgio Buarque de Holanda 777, Cidade Universitária, 13083-859 Campinas-SP, Brazil.
authors.forename: Kleber R
authors.initials: KR
authors.lastname: Pirota
authors.affiliation: Faculdade de Engenharia Elétrica e Computação e Centro de Componentes Semicondutores, Universidade Estadual de Campinas , Avenida Albert Einstein 400, 13083-852 Campinas-SP, Brazil.
authors.forename: Stanislav
authors.initials: S
authors.lastname: Moshkalev
authors.affiliation: Faculdade de Engenharia Elétrica e Computação e Centro de Componentes Semicondutores, Universidade Estadual de Campinas , Avenida Albert Einstein 400, 13083-852 Campinas-SP, Brazil.
authors.forename: José A
authors.initials: JA
authors.lastname: Diniz
authors.affiliation: Laboratory for Mechanics of Materials and Nanostructures, Swiss Federal Laboratories for Materials Science and Technology (EMPA) , Feuerwerkstrasse 39, 3602 Thun, Switzerland.
authors.forename: Ivo
authors.initials: I
authors.lastname: Utke
keywords: cobalt; focused-electron-beam-induced deposition; nanofabrication; thermally induced graphitization; thermally induced oxygen tuning