Metrology of Three-Dimensional Techniques in Focused Ion Beam Microscopy

Abstract

The use of focused ion beam (FIB) microscopes to characterise the microstructure of materials in three dimensions, by reconstruction of serial sections, has rapidly grown during the last decade. This is due to improved capabilities in material characterisation and more effective control of the ion beam to cut cross sections in a wide range of materials. It is easy to assume that a visual reconstruction of a stack of images produced by FIB is a fairly accurate representation of the true 3D structure and subsequently carry out measurements based on these data. However, it will be shown that this is not straightforward and in practice, errors or uncertainties in the sectioning, imaging or mapping, and reconstruction can combine to produce misleading results. This paper discusses the metrological challenges faced, but often disregarded, in measurement of the errors and uncertainties that occur throughout FIB 3D characterisation of materials. This was done by studying image stacks and 3D reconstructions from purpose-made structures of known geometries and composition.