DIAMOND DEPOSITION ON SUBSTRATES WITH DIFFERENT GEOMETRIES IN A THERMAL PLASMA REACTOR

The effects of process parameters on diamond film deposition have been considered in an atmospheric-pressure dc thermal plasma jet reactor. Two different precursor injection systems have been evaluated, counter flow and side injection. The precursor flow rate using ethanol has bee n found to strongly affect crystal size as well as orientation of crys tal growth planes. Further, crystal size on sharp edges has been found to be up to five times larger than on planar surfaces. The effects of substrate geometry on the morphology and area of deposited diamond ha ve been investigated as well. The results of this study show that dc t hermal plasma jets can provide high diamond deposition rates, for exam ple on wires and drills, although crystal size and film thickness shoe substantial variation.