IMPLANTED ANTIMONY PRECIPITATION IN SILICON STUDIED BY MEDIUM-ENERGY ION-SCATTERING

Implantation of 50 keV Sb+ ions has been accomplished into silicon through 10 nm thermal oxides with doses ranging from 1 x 10(14) cm-2 to 1 x 10(15) cm-2. The Sb precipitation process at different annealing temperatures has been evaluated by medium-energy ion scattering (MEIS) and Raman scattering. Annealing at 900-degrees-C for 30 min causes Sb precipitation in the bulk Si at concentrations above approximately 2 x 10(20) cm-3, while at the SiO2/Si interface the precipitation occurs above 5 x 10(19) cm-3. The bulk precipitation limit is about one order of magnitude larger than that of the thermal equilibrium solid solubility of Sb (3 x 10(19) cm-3), while the precipitation at the Si surface or the SiO2/Si interface occurs at concentrations over the thermal equilibrium value.