Tomography by Atom Probe Field Ion Microscopy

Abstract

The Field Ion Microscope (FIM) introduced by E.W. Muller was the first instrument capable of imaging metal surfaces with atomic resolution in real space [1–7]. The FIM was originally employed to solve problems related to surface physics and crystallography. The field of application substantially widened when the imaging mode was supplemented by the atom probe mode. This technique finally gives the chemical composition of a sample volume with atomic spatial resolution, and the sensitivity of the chemical analysis does not depend on the atom species. These advantages led to increasing and fruitful use of the method in metal physics, materials science and engineering. While the in-depth resolution corresponds to the atomic plane distance parallel to the sample axis, the lateral resolution is essentially determined by the structure of position-sensitive ion detectors that monitor the original atom positions at the sample surface before field evaporation. Such detectors, although well known for many years in numerous areas of application, have been improved substantially for use in atom probes during the past decade. In parallel, fast and extended data acquisition and handling systems have also been developed. This chapter reviews this development and presents a number of results from materials research.