A quasianalytic kinetic model for nonequilibrium C2H2(1%)/H2/Ar RF plasmas of interest in nanocrystalline diamond growth

A general quasianalytic space-time averaged kinetic model for studying the nonequilibrium plasma chemistry of medium-pressure (0.1 Torr less than or equal to p less than or equal to 0.8 Torr) C2H2(1%)/H-2/Ar radiofrequency (RF) (13.56 MHz) plasmas has been built and used for determining simple analytic expressions for the concentrations of some species of interest in nanocrystalline diamond growth. Changes in external processing parameters (particularly initial argon concentration in the feed gas) are found to influence both the electron energy distribution function of the plasma and the different particle population densities. In agreement with recent experimental results, the model predicts an increase of, respectively, the concentration of C2H2 as a function of Ar (up to 90%) and of the concentration of C-2(a(3)Pi(u)) with growing gas pressure and Ar concentration in the plasma.