Diamond and diamond-like carbon films

Polycrystalline diamond films are grown from low pressure gas mixtures, the deposition techniques are Microwave Plasma Chemical Vapour Deposition and Hot filament Chemical Vapour Deposition, in both techniques the deposition temperature is close to 900 degrees C. The film growth process is strongly dominated by the initial nucleation stage, after this stage, the film grows at a rate of one micron per hour. The carbon atoms in the diamond film are fully fourfold (sp(3)) co-ordinated and the film properties art: close to those of single crystalline diamond: extremely hard, resistant and transparent from UV to IR. Diamond-like carbon (DLC)films are amorphous and contain a variable amount of hydrogen in their structure, the carbon atoms are partially threefold (sp(2)) co-ordinated. Films are obtained at temperatures below 250 degrees C and deposited on almost any substrate. Film composition, structure and functional properties are strongly dependent on the level of ionic bombardment of the film during growth. DLC films are very hard, have a low friction coefficient and good wear resistance, are chemically inert and are transparent in the IR. (C) 1998 Elsevier Science Ltd. All rights reserved.