Chemical vapor deposition of diamond films using water-based plasma discharges
A chemical vapor deposition (CVD) technique (process andapparatus) for the growth of diamond films using vapor mixtures ofselected compounds having desired moieties, specifically precursorsthat provide carbon and etchant species that remove graphitedisclosed. The selected compounds are reacted in a plasma createdby a confined rf discharge to produce diamond films on a diamond ora non-diamond substrate. In a preferred embodiment a gas phasemixture including at least 20% water which provides the etchantspecies is reacted with an alcohol which provides the requisitecarbon precursor at low temperature (300.degree.-650.degree. C.)and low pressure (0.1 to 10 Torr), preferably in the presence of anorganic acid (acetic acid) which contributes etchant speciesreactant. In the preferred embodiment the volumetric mixtures havetypically been 40-80% water and 60-20% alcohol. The gaseous mixtureof H.sub.2 O and alcohol is dissociated to produce H, OH, andcarbon radicals. Both OH and atomic H are capable of etchinggraphite from the depositing carbon layer. The selected compoundsare reacted in a CVD apparatus in which a confined rf discharge isused to create an electric discharge or plasma. The plasma isconfined between an inductive rf coil via transformer isolationfrom the chamber ground.
Rudder, R., Hudson, G., Hendry, R., & Markunas, R. (1995). IPC No. U.S.Chemical vapor deposition of diamond films using water-based plasma discharges (Patent No. 5418018.)