Ion bombardment was frequently used in the preparation of thin foils of a variety of materials for analysis by transmission electron microscopy and related techniques. A detailed study was made of the effects of such specimen preparation techniques upon nanometre-sized cavities in Si by comparing ion-beam milled cross-sectional specimens with those prepared using a small-angle cleavage technique. The cavities were formed by a prior implantation of energetic helium ions and a high-temperature anneal. In the specimens prepared by ion-beam techniques in two different commercial systems, there was a clear effect on the small cavities. Specifically, the cavities were observed to migrate away from the original surface at both room temperature and liquid N temperature. The effect was considered within the context of the interaction of the cavities with mobile vacancies and interstitials injected by the ion bombardment. This was believed to be an important effect that must be taken into account when using transmission electron microscopy techniques to study defects in semiconductors.

The Effect of Ion-Beam Specimen Preparation Techniques on Vacancy-Type Defects in Silicon. A.S.Gandy, S.E.Donnelly, M.F.Beaufort, V.M.Vishnyakov, J.F.Barbot: Nuclear Instruments and Methods in Physics Research B, 2006, 242[1-2], 610-3