Systematic approaches for targeting an atom-probe tomography sample fabricated in a thin TEM specimen: Correlative structural, chemical and 3-D reconstruction analyses

Sung Il Baik, Dieter Isheim, David N. Seidman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Atom-probe tomography (APT) is a unique analysis tool that enables true three-dimensional (3-D) analyses with sub-nano scale spatial resolution. Recent implementations of the local-electrode atom-probe (LEAP) tomograph with ultraviolet laser pulsing have significantly expanded the research applications of APT. The small field-of-view of a needle-shaped specimen with a less than 100 nm diam. is, however, a major limitation for analyzing materials. The systematic approaches for site-specific targeting of an APT nanotip in a transmission electron microscope (TEM) of a thin sample are introduced to solve the geometrical limitations of a sharpened APT nanotip. In addition to “coupling APT to TEM” the technique presented here allows for targeting the preparation of an APT tip based on TEM observation of a much larger area than what is captured in the APT tip. The correlative methods have synergies for not only high-resolution structural analyses but also for obtaining chemical information. Chemical analyses in a TEM, both energy-dispersive X-ray spectroscopy (EDS) and electron energy-loss spectroscopy (EELS), are performed and compared with the APT chemical analyses of a carbide phase (M7C3) precipitate at a grain boundary in a Ni-based alloy. Additionally, a TEM image of a sharpened APT nanotip is utilized for calculation of the detection area ratio of an APT nanotip by comparison with a TEM image for precise tomographic reconstructions. A grain-boundary/carbide precipitate triple junction is used to attain precise positioning of an APT nanotip in an analyzed TEM specimen.

Original languageEnglish (US)
Pages (from-to)284-292
Number of pages9
JournalUltramicroscopy
Volume184
DOIs
StatePublished - Jan 2018

Keywords

  • 3-D reconstruction
  • Atom probe tomography (APT)
  • Correlative study
  • Metal-carbide phase precipitate
  • Sample preparation
  • Transmission electron microscope (TEM)

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Instrumentation

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