Chemical stresses induced by grain-boundary diffusion in thin films

Chemical stresses induced by grain-boundary diffusion in thin films were analyzed. The stress distribution consisted of both tension and compression fields, and its characteristics were similar to those obtained for a semi-infinite solid. At a given time, the maximum stress (tension or compression) increased with increasing film thickness for both constant and instantaneous sources; it was generally higher than that in the semi-infinite system. The maximum stress (tension or compression) decreased as the diffusion time increased and at a given time and film thickness it increased with decreasing diffusivity ratio. The buildup of local stress is likely to cause damage and malfunctions of the film when used in an electronic device.