Metal initiated nucleation of diamond

Abstract

Nucleation of diamond crystallites is initiated on electrically nonconducting substrates and on semiconducting substrates at a temperatures of 650.degree. C. or lower by providing atoms of a metal in a plasma formed by activation, as by microwave energy in a vacuum chamber, of a mixture of hydrogen and a carbon containing vapor. A continuous, adhering film of polycrystalline diamond is then grown on the substrate from the nucleated crystallites. The nucleation is effective when the substrate has a positive electric potential relative to a wall of the chamber. Positive and negative dopants may be provided in the vapor to give a semiconducting film. The nucleation and film growth are effective at the relatively low substrate temperatures so that dopant diffusion and substrate damage occurring at the usual, higher diamond film deposition temperatures are avoided. Atoms of chromium, titanium, and nickel are particularly effective and may be provided by a metalorganic compound in the vapor or by a solid material which is etched by the plasma and may be the pure metal or its oxide, nitride, or alloy. The solid material may be provided as an open vessel or on a ring within which the substrate is placed or as a coating deposited on the substrate. A partial coating of the solid material results in the diamond film being selectively deposited only on the uncoated portion.