The combination of focused ion beam (FIB) sputtering with transmission electron microscopy (TEM) offers new opportunities for the nanoscale characterization of materials. The FIB may be used to prepare membranes for TEM imaging which are: (i) Site selective, i.e. the membranes may be placed with sub-micron precision in all three dimensions, (ii) Largely free of differential sputtering artifacts, such that membranes may be prepared which are of constant thickness from structures with very dissimilar materials, and (iii) Of precisely known geometry.
The challenges associated with FIB specimen preparation will also be discussed and are summarized in Figure 1: (a) Surface amorphization damage, (b) Residual differential sputtering effects, (c) Redeposition of sputtered material and (d) Membrane bowing due to internal or beaminduced stresses. It will be demonstrated that each of these effects can be sufficiently controlled to allow high quality diffraction contrast imaging in a wide range of materials.