AVS 46th International Symposium
    Plasma Science and Technology Division Tuesday Sessions
       Session PS-TuA

Paper PS-TuA7
Cavity Ring Down Spectroscopy for the Detection of Hydrocarbon Radicals during a-C:H Deposition

Tuesday, October 26, 1999, 4:00 pm, Room 609

Session: Plasma Diagnostics II
Presenter: K.G.Y. Letourneur, Eindhoven University of Technology, The Netherlands
Authors: K.G.Y. Letourneur, Eindhoven University of Technology, The Netherlands
M.C.M. van de Sanden, Eindhoven University of Technology, The Netherlands
R. Engeln, Eindhoven University of Technology, The Netherlands
M.G.H. Boogaarts, Eindhoven University of Technology, The Netherlands
D.C. Schram, Eindhoven University of Technology, The Netherlands
Correspondent: Click to Email
Cavity Ring Down spectroscopy can be used in order to quantify the relative influence of radical species impinging on a growth surface. This enhanced absorption technique allows the determination of low species ground state densities as well as the evaluation of their rotational and vibrational temperature. It also allows for time and space resolved measurements. Cavity Ring Down spectroscopy has been applied during the deposition of hard hydrogenated amorphous carbon films obtained from a remote argon arc plasma in which acetylene is injected as carbon precursor. The C@sub 2@H@sub 2@ molecules are subsequently dissociated by argon ions and electrons, present in the plasma, producing hydrocarbon radicals (C@sub 2@H@super *@ and CH@super *@) responsible for deposition (rates up to 20 nm/s). However, hitherto, to the best of our knowledge, no direct detection of the ground state of those radicals has ever been reported in such environment. Detection of the ground state of the CH and C@sub 2@H radicals via CRD spectroscopy around 430 nm and 276 nm respectively are presented. Typical ground state densities of CH of around 10@super 17@ m@super -3@ are found. The results are used to develop a model for the deposition process of hydrogenated amorphous carbon from a remote plasma.