Spectroscopic measurement of DC plasma jet in diamond synthesis

In synthesis of diamond with a plasma jet under medium pressure, the morphology of the deposited particles depends strongly on the ratio of the methane gas flow rate to the hydrogen gas flow rate and the distance from the feed ring exit to the substrate. The relationship between the morphology of the deposited particles and the chemical species in the plasma jet is studied by means of emission spectroscopy, with a view toward achieving large-area deposition at a high rate. The intensity ratio of the CH to the H-alpha spectrum is strongly correlated with the quality of the diamond synthesized and the deposition area.