AVS 53rd International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThA

Paper PS2-ThA8
Global Model of a Dual Frequency Capacitive Discharge

Thursday, November 16, 2006, 4:20 pm, Room 2011

Session: Plasma Modeling
Presenter: P. Levif, Ecole Polytechnique, France
Authors: P. Levif, Ecole Polytechnique, France
P. Chabert, Ecole Polytechnique, France
M.M. Turner, Dublin City University, Ireland
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The physics of capacitive discharges has recently been reinvigorated with the rise of interest in multiple-frequency excitation and the related need to widen the range of frequencies that are used. A major attraction of dual-frequency excitation is that it promises independent control of the ion flux and the ion energy, which is not the case in single frequency excitation. The electron heating mechanisms occurring within the dual-frequency sheath region were recently investigated by Turner and Chabert (Submitted to Physical Review Letters). It was shown that the heating (either collisional or collisionless) produced by the superposition of the two frequencies is much larger than the sum of the two frequency contributions. In the present paper, we use the heating models developed to construct a global model of a dual-frequency capacitive discharge operated in argon. For this, we must also discuss the dynamics of the sheath, s(t), to obtain the equivalent of a dual-frequency Child law which relates the applied rf voltage, the electron density and the sheath size. By coupling the power and particle balance to the Child law mentioned above, one can obtain a self-consistent solution for all the plasma parameters. As an example, for a discharge excited by the combination of 13 and 143 MHz, the electron density increases by a factor 15 when the ratio of the high-frequency current to the low-frequency current amplitude increase from zero (i.e. the single 13 MHz case) to six.