3D elemental mapping with nanometer-scale resolution using atom probe tomography (APT)

Zoom webinar | Replay on Youtube

Masoud Dialameh,

IMEC, Belgium

Atom probe tomography (APT) is a powerful microscopy technique that uniquely combines three-dimensional mapping of atomic distributions with the elemental identification for both light and heavy elements, achieving sub-nanometer spatial resolution [1]. This capability enables a variety of analysis modes for materials characterization, including voxel-based 3D composition analysis with parts-per-million sensitivity [1], cluster identification and characterization of solute clusters, precipitates, and segregated regions down to ~1 nm radius size [2], nearest-neighbour distribution analysis, and proximity histograms for interface characterization.

The physical principle of APT is based on controlled field evaporation, whereby atoms are sequentially removed from a needle-shaped specimen and identified using a position-sensitive detector coupled with time-of-flight mass spectrometry. This enables atomic-scale information to be obtained from local nanometer-sized regions of a material, in contrast to most X-ray–based techniques that provide ensemble-averaged measurements over many atoms. APT requires specimen preparation in form of needle-shaped tips with a radius below 50 nm which typically involves focused ion beam (FIB) milling.

This webinar will provide a brief introduction to the fundamentals of APT, including field evaporation process, specimen preparation, data acquisition, and 3D data reconstruction. Selected case studies on materials relevant to the circular economy and the semiconductor industry will be presented, with a focus on highlighting both the potential and the limitations of APT for analysis various material systems.

References

[1] Gault, Baptiste, et al. “Atom probe tomography.” Nature Reviews Methods Primers 1.1 (2021): 51.

[2] De Geuser, Frédéric, and Baptiste Gault. “Metrology of small particles and solute clusters by atom probe tomography.” Acta Materialia 188 (2020): 406-415.