OES study of the gas phase during diamond films deposition in high power DC arc plasma jet CVD system

This paper used optical emission spectroscopy (OES) to study the gasphase in highpower DC arc plasma jet chemical vapour deposition (CVD) during diamond films growth processes. Theresults show that all the deposition parameters (methane concentration,substrate temperature, gas flow rate and ratio of H₂/Ar) could stronglyinfluence the gas phase. C₂ is found to be the most sensitive radicalto deposition parameters among the radicals in gas phase. Spatially resolvedOES implies that a relative high concentration of atomic H exists near thesubstrate surface, which is beneficial for diamond film growth. Therelatively high concentrations of C₂ and CH are correlated with highdeposition rate of diamond. In our high deposition rate system, C₂ ispresumed to be the main growth radical, and CH is also believed tocontribute the diamond deposition.