RBS profiles have been obtained for doses of 1015, 5-1015 and 5-1016 cm-2 both in random and channeling configuration. The Ti peak is clearly observed at energies close to 1,650 keV, which is far from the maximum backscattered energy due to the
Si surface (1,330 keV). The area of this peak is proportional to the implanted dose and shows the broadening corresponding to the implantation depth that increases with the dose. Ti peaks obtained in random and channeled configurations are almost equal and the comparison of its area for the different doses shows that only a maximum of about 8% of the Ti is located at substitutional positions being therefore the most part of the implanted atoms located interstitially. Anyway, the uncertainty of these measures does not permit to obtain a real value of the substitutional percentage, which is in any case very low if any.
As a partial conclusion of the structural characterization, we can resume that for the 1015 cm-2 dose we have an almost perfect crystal with a layer of about 20 nm having a Ti interstitial concentration above the Mott limit. Higher doses produce deeper profiles but with a poorer crystalline structure.
