Improved calculation of Si sputter yield via first principles derived interatomic potential

Silicon sputter yield under medium energy Ar+ ion bombardment is calculated via molecular dynamics, using a highly accurate interatomic potential for Ar-Si interactions derived from first-principles calculations. Unlike the widely used universal repulsive potentials such as the Moliere or ZBL parameterizations, this new potential, referred to as DFT-ArSi, is developed via localized basis density functional theory. Sputter yields for Si obtained with the DFT-ArSi potential at 500 eV and 1 keV incident energies are found to be within 6% and 2% of experimental results, respectively, while errors using existing potentials are typically on the order of 11%. The DFT-ArSi potential differs from existing empirical potentials in the ∼1 Å interatomic separation range which is shown to be the most important range for modeling low-to-medium energy ion bombardment.