Center for Atom Probe Tomography (NUCAPT)

Atom-probe tomography (APT) is a microanalytical instrument producing an atom-by-atom three-dimensional reconstruction of a sample, with sub-nanometer resolution with a typical analyzed volume of about 150 x 150 x 500 nm³ . APT is particularly suitable to investigate nano-structured materials. Typical micro- and nanostructural features studied are: composition and morphology of second-phase precipitates or small clusters of solute atoms, compositional variation in modulated structures, multi-layer thin-film structures, dopant profiles of semiconductor structures (transistors), and analysis of the chemistry and topology of internal interfaces. Specimen preparation of almost any material is now possible employing a dual-beam focused-ion beam (FIB) microscope, which allows targeted sample preparation of a specific feature, such as a grain boundary or an individual transistor in a semiconductor device.