It was noted that mono-energetic positrons were widely used to study defects in near-surface regions and buried interfaces. Depth information was usually obtained by varying the positron implantation energy. However, at energies greater than 10keV, the stopping profile became much broader than the positron diffusion length. It was shown here that an optimum depth resolution could be obtained by stepwise removal of the surface, and

measurement using the smallest-possible positron implantation depth. Excellent defect depth profiles could be obtained when the sample was wedge-polished, with a bevel-angle of about 1°.

Improved Defect Profiling with Slow Positrons. R.Krause-Rehberg, F.Börner, F.Redmann, W.Egger, G.Kögel, P.Sperr, W.Triftshäuser: Applied Surface Science, 2002, 194[1-4], 210-3