Structural characterization of dual ion implantation in silicon

〈1 0 0〉 Si wafers were dual implanted at room temperature with Fe + C and Ti + C with fluences of 2 × 1017 cm−2. The samples were annealed in vacuum at 800 °C and 1000 °C respectively, and characterized in scanning electron microscope (FEG-SEM), grazing incidence X-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS). The scanning electron microscopy characterization showed that both annealings generated precipitates, with sizes within the range of 10–100 nm at 800 °C and 1–10 μm for the 1000 °C annealing. The GIXRD measurements revealed the presence of different silicides phases. For the Fe + C implantation β-FeSi2 was observed at 800 °C while at 1000 °C α-FeSi2 and SiC were found. The Ti + C sample at 800 °C showed simultaneously the presence of four different phases, both metastable C49 and stable C54 silicide TiSi2, poly-Si and SiC. At higher temperatures the metastable C49-TiSi2 silicide phase was no longer observed, all the others remaining. The XPS analysis confirmed the existence of the SiC at 1000 °C temperature, and showed that the initial carbon clusters get richer in Si with the increase of temperature to form SiC. It was also possible to see that among all present species, C was the one that oxidized the most with increasing temperature.