Luminescence of Dislocations and Oxide Precipitates in Si

Abstract

The analysis of the photoluminescence (PL) spectra of a number of silicon samples plastically deformed or simply thermally annealed was used to understand the role of oxygen and oxygen precipitates on the PL emissions in the 0.8-1.0 eV range. The results of this analysis show that it is possible to discriminate between emissions due to oxygen-associated centres and those due to dislocations. Furthermore, it has been shown on a sample presenting only (dissociated) 60° dislocations that the 0.807 eV emission is absent, demonstrating that it comes either from dislocation intersections or from screw segments. Finally, it has been suggested that the strain field associated to oxide precipitates might be responsible of both narrow and broad bands, systematically present in most of the samples examined, which are therefore interpreted as being due to carrier confinement effects in localized quantum wells at silicon/silicon oxide interfaces of oxide precipitates.