Atom probes as analytical microscopes

Abstract

Analytical microscopes are used to provide compositional and image information at spatial scales from the atomic (nm) to the macroscopic (mm). There are limitations in these techniques, however, and three in particular are noteworthy. 1) Compositional information at the atomic scale is not readily available. 2) The precision of the data is not high (limited to about a few part per thousand). 3) It is difficult or impossible to determine information about the composition in three dimensions.Atom probe field ion microscopy (APFIM) has historically been able to complement analytical electron microscopes (AEM) at the atomic scale but has not competed with them otherwise. For example, atomic-scale compositional information is inherent to APFIM but it has been difficult to extend this to large dimensions. Furthermore, APFIMs achieve single atom sensitivity which is difficult for AEMs in all but limited situations. In this paper, we consider how atom probes are evolving with capabilities which allow them to not only overcome some of the shortcomings of AEM, but also to compete directly with AEM against its strengths.