Smooth diamond films for optical applications

Optically smooth and homogeneous diamond films of mym thickness have been deposited by the combination of high nucleation density growth techniques and dynamic CVD. To overcome the scattering problem associated with grain growth in much thicker films, we studied two concepts to grow oriented diamond films. The stabilization of a smaller than 100 bigger than fibre-texture with coplanar (100) surface facets is shown to be a viable way to achieve optically smooth surfaces. Films grown from oriented seeds via bias- assisted plasma CVD offer the option of an additional azimuthal grain orientation. Their normal orientation and therefore the surface smoothness, however, is presently inferior to the fibre-textured films.