Assessing Polar And Azimuthal Correlations For An Oriented Mosaic Of (001) Diamond Crystallites On (001) Silicon

The heteroepitaxial growth of diamond films on (001) silicon by bias-enhanced, microwave-assisted chemical vapor deposition leads to a mosaic of highly oriented crystallites. The majority of crystallites adopt a ''cube-on-cube'' orientation (diamond{hkl}\\silicon{hkl}), but there are a variety of minor growth textures (including diamond (111)\\silicon(001), diamond(311)\\silicon(001), and diamond(220)\\silicon(001)). Within the diamond(001)\\silicon(001) domain, there is a distribution of crystallite orientations and concurrently heteroepitaxial relationships. The X-ray precession method has been employed here, together with the more widely adopted X-ray rocking curve technique, to assess quantitatively the nature and breadth of this distribution of orientations and its dependence on film thickness. In brief, the X-ray scattering from the mosaic of crystallites can be well approximated by simple gaussian functions, with misorientation angles of a few degrees both parallel (azimuthal) and normal (polar) to the surface of the silicon substrate. The dependence of these parameters on film thickness is, however, non-monotonic with minima near a diamond him thickness of 20 mu m.