Observation of multiple precipitate layers in MeV Au++-implanted silicon

Abstract

Room-temperature MeV Au++ implantation into silicon with energies above 1.8 MeV shows a splitting of the Au concentration profile in the Rutherford backscattering spectrometry (RBS) spectra. Cross-section transmission electron microscopy micrographs show two distinct regions of Au precipitates corresponding to the peaks in the RBS spectra. The double peaks can be explained by the segregation of Au into the highly damaged region near the end of the implant range and Au segregation along a dislocation network. These dislocations arise from dynamic beam annealing during the implant and act as paths for rapid diffusion. Precipitation occurs when the Au concentration exceeds the solubility limit. Lower energy implants resulted in the expected Gaussian distributions.