Compressive film stress in a thin, tensile heteroepitaxial film

We performed atomistic scale simulations to simulate the heteroepitaxial growth of a film with a 0.62% tensile misfit strain and monitored the stress evolution. The calculated f tf is initially compressive but increases after the first monolayer is completed. We provide theoretical and simulation evidence that this effect is associated with surface stresses. These results demonstrate that wafer curvature measurements lead to unreliable predictions of film stresses when the film is very thin.