X-ray topographic identification and measurement of plastic strains and elastic stresses in single crystallites of polycrystalline diamond layers

The well-known phenomenon of asterism is used as the basis for the development of an X-ray topographic method to identify and measure plastic strains and residual elastic stresses in single crystallites more than 3 µm in size in polycrystalline diamond layers. The amount of asterism is used as a quantitative measure of plastic strains in crystallites. The distribution of crystallites over the amount of asterism in 40-to 670-µm-thick microwave-plasma-deposited polycrystalline diamond layers is obtained. Shear plastic strains, which cause a misorientation from 0.4′ to 1.5° between different areas of a crystallite, are observed for the first time. The residual elastic stresses calculated in plastically strained crystallites vary between 2.7 kPa and 0.84 GPa.