Abstract: A method is disclosed for producing an oriented diamond film on a single crystal silicon substrate which comprises preconditioning the surface of the substrate by exposing the surface of the substrate to a carbon-containing plasma, subjecting the preconditioned surface to electrical bias to effect nucleation of the substrate surface for oriented diamond crystal growth while monitoring the completion of nucleation over the surface of the substrate and depositing crystalline diamond on the nucleated surface from a carbon-containing plasma. The resulting structure comprises a crystalline diamond film on the silicon substrate characterised by oriented columnar diamond crystals which form a substantially uniform tessellated pattern. In practice, the columnar crystals normally have a generally quadrilateral shape whose sides are mutually aligned.