Field-ion microscopy enables the visualization of individual atoms on a material’s surface, and it was developed in the 1950s by Erwin Müller. APT is an extension of FIM. Atom Probe Tomography (APT) is a highly effective microscopy technique that produces a three-dimensional (3D) atom-by-atom reconstruction of a small volume within a material. The generated 3D atom maps depict the position and identification of individual atoms in a region that may contain hundreds of millions of atoms. FIM and APT play significant role in different fields like materials science, metallurgy, and nanotechnology. MaTestLab is one of the leading testing service providers in the USA and Canada. We have a large network of testing laboratories in the USA.
Principle and Methodology of FIM/APT
Field-Ion Microscopy (FIM)
FIM operates on the principle of field ionization. In FIM, a strong electric field ionizes rare gas atoms (imaging gas) near a needle-shaped object. Ion beams are created near the sample surface and projected onto a screen (phosphorous or digital), resulting in an atomic-scale representation of the sample surface’s topography.
Atom Probe Tomography (APT)
APT extends FIM by incorporating time-of-flight mass spectrometry. An Atom Probe evaporates atoms from a small needle-shaped sample (usually < 100 nm in diameter) and projects them onto a position-sensitive detector. The detector detects the position of each atom’s impact, the order of arrival, and the duration of the atom’s trip from tip to detector. This information can be utilized to create a 3D picture of the material on an atomic scale.
Instrumentation
FIM instrumentation includes a sharp needle specimen, high voltage supply, and imaging screen for capturing and displaying ionized atoms. APT instrumentation includes a pulsed laser or voltage source for controlled atom evaporation, a time-of-flight detector for ion travel time, and a data acquisition system for 3D reconstruction of spatial and mass spectrometry data. These components work together to create a strong electric field for field ionization.
Applications of FIM/APT
FIM and APT are used in many scientific and industrial domains because of their capacity to deliver detailed atomic-level information. They are most typically used in the field of material science. They are particularly useful for studying metals, semiconductors, ceramics, and composites. However, recent advances in technology have broadened their application fields to include geological and biological sciences.
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