Method and apparatus for vapor deposition of diamond

Claim 1

A direct current plasma torch apparatus for vapor deposition comprising: a first electrode having a first polarity comprising an enclosed body defining therein a plurality of open nozzles for jetting thermal plasma and a discharge feed pipe; a second electrode disposed in said body and comprising a plurality of individual electrode elements, said second electrode having a second polarity opposite to said first polarity, said electrodes being arranged to present a discharge zone therebetween, said feed pipe being disposed for feeding a feed gas into said zone; a power source supply system for applying a direct current voltage between said electrodes at said zone to form the discharge gas that is fed to the zone into a thermal plasma and to cause said thermal plasma to be jetted through said nozzle as a plasma jet; a starting gas feeding system for feeding gaseous starting compounds for vapor phase deposition into said plasma jet; a support for supporting a substrate in the plasma jet and permitting a thermal plasma chemical vapor deposition film to be deposited from the vapor phase onto the substrate; and means for cooling the substrate by first cooling said support, said nozzles of the first electrode each having an inner wall and said electrode elements of the second electrode each being positioned adjacent a respective inner wall as so to present at least a portion of said discharge zone therebetween.