OPTICAL-EMISSION SPECTROSCOPY STUDIES OF THE EFFECTS OF NITROGEN ADDITION ON DIAMOND SYNTHESIS IN A CH4-CO2 GAS-MIXTURE

The influence of nitrogen on the growth of diamond using the gas mixtures of CHS-CO, by microwave plasma chemical vapor deposition was investigated. A clear improvement in the surface morphology and quality of the diamond films indicates the beneficial effect of adding nitrogen to CH4-CO gas mixtures. Analysis using Auger electron spectroscopy and secondary ion mass spectroscopy shows very low and uniform levels of nitrogen in the diamond films. Atomic nitrogen plays a dominant role in C/H/O/N plasma chemical vapor deposition processes because of the amount of oxygen atoms increased via the titration reaction of nitrogen atoms (a high-rate reaction): N+NO-->N-2+O. This produces a significant influence on diamond synthesis in a CH4-CO2-N-2 gas mixture. (C) 1995 American Institute of Physics.