Optical and electrical activity of boron interstitial defects in Si

Density functional theory is used to investigate boron interstitial clusters and defects formed with carbon and oxygen. Using data from experimental techniques such as deep level transient spectroscopy, and electron paramagnetic resonance, photoluminescence and infrared studies, we are able to assign structures to many observed centres and begin to develop a series of reaction paths for the evolution of boron with annealing temperature depending on the relative concentrations of impurities. Among other results we demonstrate that a metastable defect composed of two boron interstitials and a self-interstitial has symmetry, vibrational modes and an electronic structure consistent with the 12 photoluminescence Centre, also known as the Y centre.