title: Pattern shape control for heat treatment purification of electron-beam-induced deposition of gold from the Me2Au(acac) precursor.
abstract: Gold structures can be created in a scanning electron microscope (SEM) from the Me(2)Au(acac) precursor by direct writing with the electron beam. The as-deposited purity is usually poor, and a common purification approach is a post-annealing step that indeed is effective but also induces a volume reduction because of carbon loss and an undesirable reconfiguration of the gold structure, resulting in the loss of the original shape. We studied the shape change as a result of such purification, and to minimize this effect, the application of a tantalum and chromium buffer layer was investigated. These buffer materials are well-known for their good adhesion properties. We confirm by dedicated SEM, atomic force microscopy (AFM), and transmission electron microscopy (TEM) analysis that, for the creation of a uniform Au structure, tantalum is a better buffer layer material than chromium. Post-annealing of the Au electron-beam-induced deposition (EBID) patterns for 1 h at 600 °C in air resulted in a dramatic purity increase (from 8-12 atomic % Au to above 92 atomic % Au). The uncovered part of the tantalum layer can be easily etched away, resulting in a well-defined, high-purity, gold structure.
authors.affiliation: Department of Materials Science and Engineering, Royal Institute of Technology, Brinellvägen 23, 100 44 Stockholm, Sweden. anaria@kth.se
authors.forename: Anastasia V
authors.initials: AV
authors.lastname: Riazanova
authors.forename: Yuri G M
authors.initials: YG
authors.lastname: Rikers
authors.forename: Johannes J L
authors.initials: JJ
authors.lastname: Mulders
authors.forename: Lyubov M
authors.initials: LM
authors.lastname: Belova