Thick samples of B-doped chemically vapour-deposited diamond were studied in plan view, by taper section and in cross-section by means of transmission electron microscopy. Dislocations, nanotwins and grain boundaries were investigated by using diffraction

contrast techniques, and causes were found for their introduction during growth. These observations were correlated with others performed at lower magnification by scanning electron microscopy. As a result, the nature and importance of grain clusters became apparent. It was found that <110> growth favoured the introduction of geometrically determined stresses and related defects while, in <112> growth, these effects were greatly reduced. However, <110> growth produced equiaxed grain clusters while <112> growth generated elongated grain clusters.

Transmission Electron Microscopy Investigation of Boron-Doped Polycrystalline Chemically Vapour-Deposited Diamond. J.W.Steeds, A.E.Mora, J.E.Butler, K.M.Bussmann: Philosophical Magazine A, 2002, 82[9], 1741-68