Chemical vapor deposition of diamond films using water-based plasma discharges
A chemical vapor deposition (CVD) technique (process and apparatus) for the growth of diamond films using vapor mixtures of selected compounds having desired moieties, specifically precursors that provide carbon and etchant species that remove graphite disclosed. The selected compounds are reacted in a plasma created by a confined rf discharge to produce diamond films on a diamond or a non-diamond substrate. In a preferred embodiment a gas phase mixture including at least 20% water which provides the etchant species is reacted with an alcohol which provides the requisite carbon precursor at low temperature (300.degree.-650.degree. C.) and low pressure (0.1 to 10 Torr), preferably in the presence of an organic acid (acetic acid) which contributes etchant species reactant. In the preferred embodiment the volumetric mixtures have typically been 40-80% water and 60-20% alcohol. The gaseous mixture of H.sub.2 O and alcohol is dissociated to produce H, OH, and carbon radicals. Both OH and atomic H are capable of etching graphite from the depositing carbon layer. The selected compounds are reacted in a CVD apparatus in which a confined rf discharge is used to create an electric discharge or plasma. The plasma is confined between an inductive rf coil via transformer isolation from the chamber ground.