IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Tuesday Sessions
       Session PS-TuP

Paper PS-TuP7
Comparative Study of N@sub 2@/CH@sub 4@ Plasmas in Active Discharges and in Flowing Afterglow Conditions

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Plasma Deposition, Modeling, and Emerging Applications Poster Session
Presenter: R. Hrach, Charles University, Czech Republic
Authors: R. Hrach, Charles University, Czech Republic
J.C. Legrand, Universite Pierre et Marie Curie, France
A.M. Diamy, Universite Pierre et Marie Curie, France
V. Hrachova, Charles University, Czech Republic
M. Vicher, Charles University, Czech Republic
Correspondent: Click to Email
Methane is widely used in plasma processing. Experimental techniques used for the decomposition of methane into simpler hydrocarbons can be divided into two groups - processing in active discharges and processing in flowing afterglow conditions. While the first group of discharges can lead to preparation of solid products, the lower energies in afterglows are much more convenient for efficient gaseous chemistry. The aim of this contribution is to give an insight into the basic mechanisms leading to decomposition of methane and preparation of both solid and gaseous stable products in various experimental conditions. Therefore, a computer experiment describing the N@sub 2@/CH@sub 4@ plasma was prepared and both the common features and differences of methane decomposition in various types of discharges were discussed. Models consisted of reactions between neutral, charged and excited species. Input data were derived from Langmuir probe measurements and from emission optical spectroscopy. For the solution a macroscopic kinetic approach based on balance equations of individual species was used. In order to reduce the resulting models (consisting of more than 300 and 166 reactions - in active discharges and in flowing afterglow conditions, respectively) a method of reduction of the kinetic scheme was applied. In the discussion the fluxes of carbon and nitrogen atoms were studied in the dependence on concrete experimental conditions and an attention was devoted both to the methodology of simulation and to the reduction technique in plasma chemistry.