Focused ion beams and FIB-SEMS are used for a broad range of applications, many of which are covered in brief below (Figure 1). Many applications combine aspects of these basic methods, and are described in greater detail in the technique’s page.
Cross-sectioning: Sample features which are underneath the sample surface can be exposed and analyzed with cross-sectional analysis. The advantage of FIB cross-sections over conventional cross-sectioning methods is that the area of interest, including nano-sized features, can be selected with nanometer precision. This high spatial precision is impossible with any other current technique. The example in Figure 1 displays the delamination of an anodized aluminum oxide layer and void formation underneath the aluminum oxide layer.
FIB Tomography: Samples can be repeatedly sectioned and then imaged. The acquired images are then stacked and can be used to reconstruct a 3D model of the sample. The example in Figure 1 shows a bacterium on a dragonfly wing.
Lamella Preparation: The most dominant FIB technique, besides nanostructuring, is TEM lamella preparation. At this stage the Ga FIB/SEM is the ideal tool for this. This technique allows you to prepare a sub 100nm thin TEM section from a precisely selected area of your bulk sample.
Nano/Microstructuring: FIBs are able to structure a wide range of patterns from the nanometer to large micron scale. Examples include arrays of nanopores, plasmonic devices, microfluidic channels and complex 2D and 3D structures. The example in Figure 1 shows a nanostructured Eddi (Iron Maiden’s mascot) which is so small that 64 billion of it fit into a single raindrop.
Micropillars: FIBs allow to cut nano- and micro-sized pillars into the sample. These pillars are conventionally used for nano-indentation experiments which test the mechanical properties of a sample. These structures can be either cut with Xe, Ga or Ne. Which ion species is used depends on the required sample size (you will learn which ion species to choose).
Analysis: FIB/SEMs (Ga and Xe) are conventionally equipped with a wide range of detectors like BSE, in lens, EBSD, STEM etc) to allow in situ sample analysis of the sample surface, cross-sections or volumes. The ion beam is used for cutting and the electron beam for analysis. The HIM excels at imaging sample surfaces and non-conductive samples. Analysis capabilities were recently added to the HIM with a secondary ion mass spectrometer (SIMS). The example in Figure 1 shows a false color image of molybdenum disulfide on graphene.
APT Tip Preparation: FIBs are used to prepare APT samples at precisely selected points. The overall process is similar to TEM lamella preparation. Instead of a sub 100nm thin foil, you are creating a 15µm long needle with a tip diameter of less than 100nm.
