STRONG SEGREGATION GETTERING OF TRANSITION-METALS BY IMPLANTATION-FORMED CAVITIES AND BORON-SILICIDE PRECIPITATES IN SILICON

We have mechanistically and quantitatively characterized the binding o f transition-metal impurities in Si to cavities formed by He implantat ion and to B-Si precipitates resulting from B implantation. Both sinks are inferred to act by the segregation of metal atoms to pre-existing low-energy sites, namely surface chemisorption sites in the case of c avities and bulk solution sites in the case of the B-Si phase. These g ettering processes exhibit large binding energies, and they are predic ted to remain active for arbitrarily small initial impurity concentrat ions as a result of the segregation mechanisms. Both appear promising for gettering in Si devices.