The stress in film/substrate systems was analysed by taking into account the coupling effects of diffusion and thermal misfit within the framework of Fick’s second law. A solution for diffusion-induced stress in a film/substrate system, involving thermal misfit stress feedback, was developed. The effects of the modulus ratio, diffusivity ratio and thickness ratio of the substrate and the film, and the effect of the partial molar volume of the diffusing component upon the stress distribution in the film/substrate system were then analyzed using finite difference methods. The results indicated that the stresses in the film/substrate system varied with diffusion time. Diffusion increased the magnitude of the film stress when the thermal misfit stress was compressive in the film. Moreover, the absolute values of stress in the film increased with increasing modulus ratio of the substrate and film, while they decreased with increasing partial molar volume of the diffusing component and diffusivity ratio of the substrate and film.

Stress in Film/Substrate System due to Diffusion and Thermal Misfit Effects. S.S.Shao, F.Z.Xuan, Z.Wang, S.T.Tu: Journal of Physics D, 2009, 42[17], 175413