Pulsed-voltage atom probe tomography of low conductivity and insulator materials by application of ultrathin metallic coating on nanoscale specimen geometry

Vahid R. Adineh, Ross K.W. Marceau, Yu Chen, Kae J. Si, Tony Velkov, Wenlong Cheng, Jian Li, Jing Fu

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4 Citations (Scopus)

Abstract

We present a novel approach for analysis of low-conductivity and insulating materials with conventional pulsed-voltage atom probe tomography (APT), by incorporating an ultrathin metallic coating on focused ion beam prepared needle-shaped specimens. Finite element electrostatic simulations of coated atom probe specimens were performed, which suggest remarkable improvement in uniform voltage distribution and subsequent field evaporation of the insulated samples with a metallic coating of approximately 10 nm thickness. Using design of experiment technique, an experimental investigation was performed to study physical vapor deposition coating of needle specimens with end tip radii less than 100 nm. The final geometries of the coated APT specimens were characterized with high-resolution scanning electron microscopy and transmission electron microscopy, and an empirical model was proposed to determine the optimal coating thickness for a given specimen size. The optimal coating strategy was applied to APT specimens of resin embedded Au nanospheres. Results demonstrate that the optimal coating strategy allows unique pulsed-voltage atom probe analysis and 3D imaging of biological and insulated samples
Original languageEnglish
Pages (from-to)150-159
Number of pages10
JournalUltramicroscopy
Volume181
DOIs
Publication statusPublished - 1 Oct 2017

Keywords

  • Atom probe tomography
  • Physical vapor deposition
  • Nanospheres

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