Equilibrium and kinetic surface segregations in Cu–Sn thin films

Equilibrium and kinetic surface segregations in Cu–Sn thin films are simulated based on the modified Darken model for a finite sized system. The simulations are carried out for all compositional ranges and film thicknesses. The segregation energy and the interaction parameter for the simulation are determined respectively by the Miedema model and from the thermodynamic data used for the Cu–Sn phase diagram calculation. The strong negative interaction parameter restrains Sn surface segregation in the Cu–Sn system. The size effect on surface segregation depends on the segregation energy, interaction parameter, initial bulk concentration, temperature and film thickness.