Effect of surface on defect creation by self-ion bombardment of Si(001)

We have studied defect formation and defect distributions in silicon under low-energy (25--800 eV) self-bombardment of the 2×1 terminated Si(001) surface. We applied the classical molecular dynamics technique and collected statistically significant averages to be able to detect defect production trends in the energy dependence. The number of defects created in implantations was found to be a superlinear function of energy at low energies (<400eV) and larger than the defect production in the bulk up to about 1 keV. We have also examined the depth dependence of close-to-surface damage and explored the energy and time dependence of the defect creation mechanisms and the sensitivity of the results to the choice of the model potential.