On the nature of extended defects in CVD diamond and the origin of compressive stresses

Abstract

Abstract Diffraction contrast transmission electron microscopy has been used in a detailed investigation of the nature of defects in thick square-faceted CVD diamond films. It is concluded that each crystallite progresses from octahedral growth with {111} facets to truncated octahedra before reaching the final form with large square facets. Open-faced tetrahedral defects are formed on the {111} faces of the octahedra with faults or very thin twins on the three {111} planes inclined to each facet growth surface. By micro-Raman experiments on individual grains of electron transparent regions and electron-energy-loss spectroscopy, it was shown that the defective regions are associated with the incorporation of non-diamond carbon and a model is proposed, based on this information, to account for the very high compressive stresses that have been found in these diamond films.