A Monte Carlo study of low-energy oxygen implants into amorphous tin. Competition between stoichiometry requirements and implant capabilities

In films of metallic oxides grown by ion-assisted techniques, the requirement of a controlled stoichiometry poses severe limits on the shape of both profiles of implanted ions and of displaced target atoms. Therefore, the evaluation of these profiles deserves an accurate study, especially if one considers that the lattice forces of these uncommon targets are ill-known. In this work, a Monte Carlo simulation method of the dynamical type has been used to describe the low-energy (i.e. with Ek in the range few KeV or lower) implants of oxygen ions into an amorphous tin matrix. Furthermore, for the purpose of a realistic evaluation of the displacement energy Ed, quantum mechanical calculations of the binding energy in SnnOm clusters have also been made. The results of the calculations indicate that the desired stoichiometry can be obtained, provided Ek is properly chosen. However, the shape of the ion profiles is critical at all energies and important effects arise from the choice of Ed