Gettering of Cu to hydrogen-induced cavities in Si

Gettering sites comprising dislocations and voids have been formed in silicon at a depth of 0.8 μm by room-temperature implantation with 80 keV energy protons to a fluence of 3 × 1016 cm−2, followed by annealing at a temperature of 800 °C for 20 min. Copper was evaporated onto the Si surface then diffused by heating at 600 °C for times between 5 and 60 min. Subsequently, positron annihilation measurements were used to profile the samples for void and (or) vacancy content. Rutherford backscattering quantified metal trapping out of the diffusion profile to the gettering sites. Transmission electron micrographs identified Cu trapping at both dislocations and voids. Cavities exhibit different morphologies between the empty (void) and filled condition; the latter are strongly faceted and found to contain bulk silicide.