Interaction between transition metals and point defect clusters in silicon characterized by photoluminescence

We measured the photoluminescence (PL) spectra of Si implanted with 90-keV P+ to a dose of 5×1012 atoms/cm2 and contaminated with various transition metals (W, Hf, Fe, Cu, and Ni). After annealing at 400-700 °C for 5 min in N2, several lines and bands, which are considered to originate from various point defect clusters, were observed in the PL spectra. We found that some of these lines and bands in the contaminated samples were weaker in intensity than in the samples without contamination and that the intensity depended on the transition metal. We consider that the coupling between metal atoms and point defect clusters causes the decrease in the concentration of luminescence centers and that the dependence of PL intensity on the transition metal is due to the difference in the strength of coupling between metal atoms and point defect clusters.