The first successful results of FIM specimen preparation by the focused
ion beam (FIB) technique was reported by Larson et al. [1-4]. They applied
the FIB technique to prepare FIM specimens from multilayer thin films.
By fabricating pre-thinned blank specimen using annular ion beam, they
succeeded in preparing FIM tips from multi-layer thin films in the perpendicular
direction to the film. By this method, they succeeded in analyzing chemical
compositional change at the interface of multi-layers with an atomic layer
resolution.
The FIB technique can be applied not only to thin films but also to the
standard metallic specimens. Thus, if the tip preparation process using
FIB is established as a routine process, it will become possible to prepare
tips even from the samples that used to be difficult to prepare by the
standard electropolishing technique. This should make a significant contribution
to widening the application of the atom probe technique.
The above figure show how to prepare a FIM tip using the FIB technique. The above specimen contains mechanically milled pearlite powder consolidated with iron powder binder. Contrast appears from each grain in the Ga ion image, so it is possible to distinguish which part is mecanically milled power of our interest. Looking at the ion image, it is possble to prepare sharp needle like specimen so that mechanically milled power comes to the speciemen tip. By this way, it became possible to perform atom probe analysis from mechanically milled powders [5]
