MICROSTRUCTURAL DIFFERENCE BETWEEN PLATINUM AND SILVER TRAPPED IN HYDROGEN-INDUCED CAVITIES IN SILICON

The gettering of implanted Pt and Ag to hydrogen-induced cavities in S i has been compared for doses from 1x10(13) to 1x10(15) cm(-2). After annealing at 850 degrees C for 1 h, almost 100% of both implanted meta ls were relocated to the cavity band for doses less than 1x10(14) cm(- 2). At higher doses, large differences were observed in the gettering behaviour of Pt and Ag, where the amount of Pt was saturated at close to a monolayer coverage of cavity walls, whereas the Ag accumulation a t cavities continually increased with dose Cross-sectional transmissio n electron microscopy revealed strong differences in the ability of Pt and Ag to form a bulk phase at the cavities. The results indicate tha t stable silicide formation at the near-surface and trapping of Ag to implantation damage are the main processes which limit gettering at th e higher doses. (C) 1998 American Institute of Physics.