Different approaches for methane plasmas modeling

The gas-phase behavior of a methane glow discharge was studied through three different approaches: the former based on a detailed kinetic model, the second based on the traditional thermodynamic equilibrium assumption and the latter based on the statistical fragmentation theory. In particular, the extension of the statistical fragmentation approach, originally developed for photoionization systems, to plasma-enhanced chemical vapor deposition reactors was here considered for the first time. The predictions of the three models were then compared with the available literature data and a good agreement was found between the radical species concentrations predicted by the kinetic model and those experimentally measured. Beside that, a good qualitative agreement was also found when the gas phase composition was calculated through the statistical fragmentation approach, particularly at a high methane dissociation level (i.e. for a high power discharge) and thus suggesting its reliable application to systems for which kinetic data are not available. (C) 1998 Elsevier Science Ltd. All rights reserved.