Stuttgart 2012 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 5: Niedertemperaturplasmen

P 5.4: Vortrag

Montag, 12. März 2012, 14:45–15:00, V57.03

Hydrocarbon film deposition on inner surface of tubes using leader discharge at atmospheric pressure conditions — •Ramasamy Pothiraja, Nikita Bibinov, and Peter Awakowicz — Institute for Electrical Engineering and Plasma Technology, Ruhr-University Bochum, Germany.

Hard hydrocarbon film is deposited on inner surface of glass tubes using leader discharge at atmospheric pressure in Ar/CH4 mixture. Under similar condition, soft film is deposited with high film growth rate in Ar/C2H2 plasma. In order to understand these differences, plasma parameters of leader discharge are determined using OES, V-I measurement, microphotography and numerical simulations. Plasma chemical kinetics is simulated. Using chemical kinetics simulated for different gas mixture, deposition rate and film properties are interpreted as follows, 1. Precursor molecules are ionized and dissociated mainly through charge exchange reaction with argon ions. 2. In both cases, C2H species is produced very effectively. 3. Because of low quantity of hydrogen in Ar/C2H2 mixture, C2H species dominates in film deposition processes, which facilitates incorporation of sp1 carbon in the film. 4. Presence of high quantity of atomic hydrogen in Ar/CH4 case facilitates i). regeneration of acetylene from the reactive species C2H, and ii). removal of loosely held sp1 carbon from the film surface; thus reducing film growth rate and improving film hardness. Influence of hydrogen composition on properties of deposited film is confirmed by obtaining the similar film quality for both methane and acetylene plasma system by external admixing of hydrogen in Ar/C2H2 plasma.