ON THE NATURE OF EXTENDED DEFECTS IN CVD DIAMOND AND THE ORIGIN OF COMPRESSIVE STRESSES

Diffraction contrast transmission electron microscopy has been used in a detailed investigation of the nature of defects in thick square-fac eted CVD diamond films. It is concluded that each crystallite progress es from octahedral growth with {111} facets to truncated octahedra bef ore reaching the final form with large square facets. Open-faced tetra hedral defects are formed on the {111} faces of the octahedra with fau lts or very thin twins on the three {111} planes inclined to each face t growth surface. By micro-Raman experiments on individual grains of e lectron transparent regions and electron-energy-loss spectroscopy, it was shown that the defective regions are associated with the incorpora tion of non-diamond carbon and a model is proposed, based on this info rmation, to account for the very high compressive stresses that have b een found in these diamond films. Published by Elsevier Science S.A. A ll rights reserved.