Year: 2010
Type: article
Abstract: Atom Probe Tomography (APT) is an emerging technology used to analyze the three-dimensional structure of a variety of substances at resolutions in the sub-nanometer range.A strong electric field (~20 V/nm) coupled with a sharp needle-shaped specimen (~100 nm diameter end-form) and a twodimensional detector create a point-projection microscope whereby ions are field-evaporated from the surface and diverge to the detector creating a highly-magnified projection of the specimen surface [1].The specimen preparation challenge is to form prospective materials into a sharp-needle geometry that also allows them to maintain structural integrity while exposed to an extreme electric field.The development of Focused-Ion-Beam-based TEM lift-out techniques and subsequent transfer of these techniques to APT has made it possible to ion-mill microscopic regions from a variety of solid bulk materials into a geometry appropriate for APT [2].Unfortunately, not all materials with the correct shape survive application of the required electric field without premature failure, and not all needle geometries provide the same results [3].Nevertheless, evaluation of the potential to analyze new materials with APT must start with the manufacture of specimen tips followed by assessment of analysis yield and data quality.Variation of tip shape, tip composition, and analysis conditions ultimately affect the ability of these specimens to survive analysis and yield interpretable data.
Source: Microscopy and Microanalysis
Authors: TJ Prosa, M Greene, TF Kelly, J Fu, K Narayan, S Subramaniam
Institution: National Institutes of Health
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2069150067