Self-excitation of the plasma series resonance in radio-frequency discharges: An analytical description
- Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44780 Bochum (Germany)
Self-excited plasma series resonances (PSR) are observed in capacitve discharges as high-frequency oscillations superimposed on the normal rf current. This high-frequency contribution to the current is generated by a series resonance between the capacitive sheath and the inductive and ohmic bulk of the plasma. The nonlinearity of the sheath leads to a complex dynamic. The effect is applied, e.g., as a diagnostic technique in commercial etch reactors where analysis is performed by a numerical model. Here a simple analytical investigation is introduced. In order to solve the nonlinear equations analytically, a series of approximation is necessary. Nevertheless, the basic physics is conserved and excellent agreement with numerical solutions is found. The model provides explicit and simple formula for the current waveform and the spectral range of the oscillations. In particular, the dependence on the discharge parameters is shown. Further, the model gives insight into an additional dissipation channel opened by the high-frequency oscillations. With decreasing pressure, the ohmic resistance of the bulk decreases as well, while the amplitude of the PSR oscillations grows. This results in substantially higher power dissipation that exceeds the contribution of classical stochastic heating.
- OSTI ID:
- 20860465
- Journal Information:
- Physics of Plasmas, Vol. 13, Issue 12; Other Information: DOI: 10.1063/1.2397043; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMPLITUDES
APPROXIMATIONS
DIAGNOSTIC TECHNIQUES
DIFFERENTIAL EQUATIONS
ELECTRIC CONDUCTIVITY
ELECTRIC CURRENTS
EXCITATION
HIGH-FREQUENCY DISCHARGES
HIGH-FREQUENCY HEATING
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
OSCILLATIONS
PLASMA
PLASMA SHEATH
PLASMA WAVES
RADIATION TRANSPORT
RADIOWAVE RADIATION
RESONANCE
WAVE FORMS