Impact of isovalent defect engineering strategies on carbon-related clusters in silicon

Abstract

In electron-irradiated silicon (Si) the formation of oxygen-vacancy pairs (VO or A-centers) is deleterious and for this reason isovalent defect engineering strategies have been proposed to suppress their concentration. Carbon-related clusters such as CiOi and CiCs are also important as they are electrically active and their properties need to be determined. The present study has two aims. The first aim is to review the impact of isovalent doping [germanium (Ge), tin (Sn) and lead (Pb)] on the thermal stability of the CiOi and CiCs pairs in Si by means of infrared (IR) spectroscopy. The second aim is to analyze these results and show that the presence of isovalent dopants in Si reduces the temperature of annealing (Tann) of the CiOi pairs and increases the temperature of annealing of the CiCs pairs. The results are discussed in view of recent experimental and theoretical studies. It is suggested that the change in the thermal stability of the C-related defects is due to the local strains induced in the lattice by the oversized isovalent dopants. It is surmised that these strains have an opposite impact on the Tann of the CiOi and CiCs pairs as a result of their different structures.