How material properties affect depth profiles - Insight from computer modeling

A previously developed steady-state statistical sputtering model (SS-SSM) is useful for interpretation of molecular dynamics (MD) simulations of repetitive bombardment. This method is applicable to computer modeling of depth profiling. In this paper, we demonstrate how the formalism provided by SS-SSM is used to identify the factors that determine the depth resolution of δ-layer depth profiling. The analysis is based on MD simulations of repetitive keV C₆₀ bombardment of coinage metal samples. The results show that the primary dependence of the depth profiling quality is on the sample binding energy, with bigger binding energies giving better depth resolution. The effects of sample atom mass and surface opacity are also discussed.