Microstructures of diamond formed by plasma-assisted chemical vapor deposition

Abstract

The microstructures of five different diamond films formed by plasma-assisted chemical vapor deposition have been studied by transmission electron microscopy. The films were selected for study based on differences in their surface morphologies. The preferred orientations inferred from the symmetries of the crystals observed on the surfaces of these films were consistent with those measured by x-ray diffraction. A general characteristic of all of the diamond film microstructures was stacking faults and microtwins on {111} planes, but the densities and the distributions of the defects varied widely among the films. The observations of microstructure indicate that when a crystal grows so that {100} facets are formed, stacking faults and microtwins are confined to regions near its boundaries, and when a crystal grows so that {111} facets are formed, stacking faults and microtwins are distributed throughout its volume. Under some deposition conditions the defects are confined to bands in the crystal, and coincidence of these defect bands with small steps on the crystal facets suggests that the steps may be caused by the intersection of the bands with the surface.