Rutherford backscattering and electron microscopy study of annealing behavior of MeV implanted gold in silicon

Abstract

Rutherford backscattering spectrometry (RBS) and cross-sectional transmission electron microscopy (XTEM) have been used to study the annealing behavior of MeV Au implanted in Si. Room temperature implantations of 1.5 MeV Au 2+ ions were carried out into Si(1 1 1) single crystals to doses varying from 4 × 10 13 to 4 × 10 15 cm −2. Isothermal annealing treatments were carried out in flowing Ar in a temperature range of 550–950 °C. Significant out-diffusion of Au has been observed after 1 h annealing at or above 750 °C. Upon annealing the Gaussian profile of the implanted Au atoms has been found to evolve into a bimodal distribution with a small peak at Au end-of-range (EOR) and a broad distribution in the near-surface region. XTEM measurements reveal the presence of a layer of Au precipitates at the Au EOR damage and a pronounced Au pile-up in the highly defected near-surface region. The out-diffusion behavior of Au is seen to be strongly influenced by the evolving extended defect structures which mediate rapid pipe diffusion. The thermal stability of the extended defect structures regarding Au out-diffusion and gettering have also been investigated at 850 °C as a function of the annealing time.