The study of lattice damage using slow positrons following low energy B+ implantation of silicon

The drive beyond sub-250 nm device structures requires a concomitant reduction in ion implantation energies to below keV. Such low energies are presenting new challenges for the understanding of defects created by the implantation process. Although positron annihilation spectroscopy (PAS) is a well-proven technique for studying radiation-induced damage, it has only recently been applied to vacancy-type defects induced by low energy implantation. This paper presents measurements of defect profiles following 2–100 keV implantation of B+ of Cz and epitaxially grown Si. The extraction of data relating to the defect profiles and their dependence on impurity content and the proximity of the surface are described. Further, we discuss results for annealed samples that show the sensitivity of diffusing positrons to the presence of electric fields following the creation of p–n structures.