Abstract

Residual stress in polycrystalline diamond films deposited from a DC arc plasma on ten different substrate materials (SiO₂, Si, SiC, Mo, Cu, Ni, Fe-Ni alloy, WC-Co and steel) was measured using micro Raman spectroscopy and X-ray diffraction technique. To improve adhesion some metals were precoated with a thin buffer layer of tungsten. The measured stress correlates with expected thermal stress originated from a mismatch in coefficients of thermal expansion (CTE) for diamond and substrate materials. The highest compressive stress at room temperature σ =-11.4 GPa has been found at Ni substrate, and it increased to -14.3 GPa at T=78 K, while the stress was strongly relaxed at copper because of its plasticity. The stress values determined from Raman spectra using a biaxial stress model are in good agreement with data obtained from X-ray diffraction.