X-RAY-DIFFRACTION IMAGING OF MAN-MADE AND NATURAL DIAMOND

Natural diamond crystals, intended for use as substrates for chemical vapor deposition growth of homoepitaxial diamond films and man-made diamond crystals have been studied by X-ray diffraction imaging (topography) using the National Institute of Standards and Technology materials science X-ray beam line at the National Synchrotron Light Source. An examination of type Ia, type IIa and type IIb natural crystals has shown that, in general, type Ia material is less strained with a better-defined microstructure and with less variation among samples. The type II samples show a large degree of variation in residual strain and a disrupted microstructure resulting from a large number of crystalline imperfections. The high temperature, high pressure process for growth of man-made diamond yields crystals that are almost always superior to commercially available natural material.