Intrinsic stresses in polycrystalline CVD diamond films have been related to restructuring at grain boundaries. It is speculated that reducing the interfacial energy induces an elastic tensile strain. There apears to be a correlation between the evolution of macroscopic stresses in the entire sample and localized, non-homogeneous stresses in the microstructure based on Raman Spectroscopy and x-ray diffraction pole figures. A multistep processing sequence developed previously can help reduce these stresses substrantially, by using an intermediate annealing step when the diamond grains are partially coalesced. Our results suggest that small changes in the film microstructure due to annealing can reduce both homogeneous and non-homogeneous stresses.
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