Computer simulation of ion channeling in Si containing structurally relaxed point defects

Atomistic simulation of ion channeling in Si shows that the lattice deformation around point defects, calculated by empirical potentials, gives a significant contribution to the backscattering yield of He ions channeled along major axial or planar directions. This effect,whose amount depends on defect type, beam-alignment condition and model potential used to relax the system, is expected to have consequences on the interpretation of Rutherford backscattering channeling analysis. A model of structurally relaxed point defects, including split-<110> interstitials and vacancies, has been applied to the interpretation of multiaxial channeling analysis in the slightly damaged surface region of Si implanted with MeV ions. Despite the simple microscopic structure of damage assumed in the model, the method leads to a signi cantly better agreement with experiments then the standard models which treat defects as individually displaced atoms in an unperturbed lattice.