Recently, a strong metal gettering in Si after ion implantation and annealing was detected at depths between the surface and the mean projected ion range RP (RP/2 effect), indicating the presence of residual defects therein. These defects were attributed to excess vacancies generated in the RP/2 region by the ion implantation process. So far, the defects at RP/2 were considered to be too small to be visible by transmission electron microscopy. It was shown that the crucial point for visualization of the vacancy-type defects at RP/2 by transmission electron microscopy was the specimen preparation technique. The very widely used conventional ion-milling technique for transmission electron microscopic specimen preparation introduces damage on the surface of the specimen, which blurs the original defect structure at RP/2 and obscured it from visualization. Only transmission electron microscopic specimens prepared by cleaving reveal cavities at RP/2. Minimum damage production caused during the preparation of the transmission electron microscopic specimen permitted the imaging of cavities at RP/2.

Visualization of Vacancy-Type Defects in the RP/2 Region of Ion Implanted and Annealed Silicon. A.Peeva, R.Koegler, W.Skorupa: Nuclear Instruments and Methods in Physics Research B, 2003, 206, 71-5