XRD stress analysis of CVD diamond coatings on SiC substrates

The XRD Omega method was used to determine the residual stress in a CVD diamond coating deposited on a SiC substrate. The (4 0 0) plane of CVD diamond was used with a tilt angle (ψ) from 0 to 60 degrees. A compressive stress of ≈130 MPa with a standard deviation (SD) value of 28 MPa was obtained. Stress results obtained from the indentation method and Raman spectroscopy analysis were also compared with the XRD stress values. Indentation testing of the CVD diamond was performed using a microhardness tester with a Vickers diamond indenter under a load of 1–2.5 kgf. All stress values obtained correlated closely to results obtained by XRD. These results collectively illustrate that these coatings contain compressive stress associated with their deposition process.