Temporal structure of electron heating in asymmetric single-frequency and dual-frequency capacitive discharges

Ziegler, Dennis; Mussenbrock, Thomas; Brinkmann, R. P.

doi:10.1063/1.3076206

Cited by 23 publications

(35 citation statements)

References 34 publications

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“…Of course, the amplitude of these PSR oscillations is very small compared to the total current amplitude due to the relatively small asymmetry. This is different from the "classical" scenario of the PSR self-excited in geometrically asymmetric discharges [65,[86][87][88][89][90][91], where usually ε 1 and NERH (Nonlinear Electron Resonance Heating) gives a large contribution in the electron heating [65,87,92]. Due to the symmetry parameter ε shown in Fig.…”

Section: Control Of the Self-excitation Of Psr Oscillationsmentioning

confidence: 75%

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Control of plasma properties in capacitively coupled oxygen discharges via the electrical asymmetry effect

Schüngel¹,

Zhang²,

Iwashita³

et al. 2011

J. Phys. D: Appl. Phys.

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To cite this version:E Schüngel, Q-Z Zhang, S Iwashita, J Schulze, L-J Hou, et al.. Control of plasma properties in capacitively coupled oxygen discharges via the electrical asymmetry effect. Journal of Physics D: Applied Physics, IOP Publishing, 2011, 44 (28) Abstract. By using a combined experimental, numerical and analytical approach, we investigate the control of plasma properties via the Electrical Asymmetry Effect (EAE) in a capacitively coupled oxygen discharge. In particular, we present the first experimental investigation of the EAE in electronegative discharges. A dual-frequency voltage source of 13.56 MHz and 27.12 MHz is applied to the powered electrode and the discharge symmetry is controlled by adjusting the phase angle θ between the two harmonics. It is found that the bulk position and density profiles of positive ions, negative ions, and electrons have a clear dependence on θ, while the peak densities and the electronegativity stay rather constant, largely due to the fact that the time averaged power absorption by electrons is almost independent of θ. This indicates that the ion flux towards the powered electrode remains almost constant. Meanwhile, the dc self-bias and, consequently, the sheath widths and potential profile can be effectively tuned by varying θ. This enables a flexible control of the ion bombarding energy at the electrode. Therefore, our work proves the effectiveness of the EAE to realize separate control of ion flux and ion energy in electronegative discharges. At low pressure, the strength of resonance oscillations, which are found in the current of asymmetric discharges, can be controlled with θ.

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Section: Control Of the Self-excitation Of Psr Oscillationsmentioning

confidence: 75%

“…The self-excitation of the plasma series resonance (PSR) is an important issue in asymmetric capacitive discharges operated at low pressures, because it enhances the electron heating [65,67,[73][74][75][76][86][87][88][89][90][91][92]. Due to Eq.…”

Section: Control Of the Self-excitation Of Psr Oscillationsmentioning

confidence: 99%

Control of plasma properties in capacitively coupled oxygen discharges via the electrical asymmetry effect

Schüngel¹,

Zhang²,

Iwashita³

et al. 2011

J. Phys. D: Appl. Phys.

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“…The ions gain energy dominantly due to the acceleration toward the electrodes by the voltage drop across the sheaths. 1,26 There are different electron heating mechanisms in a CCRF discharge, 1,5,7,9,16,19,[27][28][29][30][31][32][33][34][35][36] e.g., Ohmic and stochastic heating. A detailed discussion of the different electron heating mechanisms is beyond the scope of this work.…”

Section: A Energy Balances For Electrons and Ionsmentioning

confidence: 99%

Power absorption in electrically asymmetric dual frequency capacitive radio frequency discharges

et al. 2011

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The symmetry of capacitive radio frequency discharges can be controlled via the electrical asymmetry effect by driving one electrode with a fundamental frequency and its second harmonic. In such electrically asymmetric discharges, the mean ion energies at both electrodes are controlled separately from the ion flux by tuning the phase angle between the harmonics at fixed voltage amplitudes. Here, the question why the ion flux is nearly independent of is answered by investigating the power absorbed by the electrons P e as a function of and time experimentally, by a particle in cell simulation, and an analytical model. The dynamics of P e is understood by the model and is found to be strongly affected by the choice of. However, on time average, P e is nearly constant, independently of. Thus, the ion flux remains approximately constant. In addition, it is shown that the absolute value of the individual voltages across the powered and grounded electrode sheath vary linearly with the dc self-bias. However, their sum remains constant. This yields, in combination with the constancy of the ion flux, a constant power absorbed by the ions and, in conclusion, a total power absorption that is independent of .

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“…There are various physical mechanisms that produce coupling and nonlinear interactions between the two frequencies. 3,23,[32][33][34][35][36] The electron dynamics governed by both frequencies simultaneously is significantly more complex and not yet fully understood. In practice, one could not achieve the complete independent control of the ion flux and ion energy.…”

Section: Introductionmentioning

confidence: 99%

Effects of gas pressure on 60/13.56 MHz dual-frequency capacitively coupled plasmas

Yuan

Yin

et al. 2011

Physics of Plasmas

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The electron energy probability functions (EEPFs) were measured with increasing gas pressure in 60/13.56 MHz dual-frequency capacitively coupled plasma (DF-CCP) using compensated Langmiur electrostatic probe. The transition pressure of heating mode from collisionless to collisional heating in 60/13.56 MHz DF-CCP is found to be significantly lower than that in 13.56 MHz single-frequency CCP. As the pressure increases, the EEPFs change from bi-Maxwellian to Druyvesteyn type which is similar with that in 60 MHz single-frequency CCP. The pressure dependence of electron densities, effective electron temperatures, floating potentials, and plasma potentials in 60/13.56 MHz DF-CCP were measured and were compared with that in 60 MHz single-frequency CCP. The pressure dependence of these plasma parameters in 60/13.56 MHz DF-CCP is similar with that in 60 MHz single-frequency CCP.

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Temporal structure of electron heating in asymmetric single-frequency and dual-frequency capacitive discharges

Cited by 23 publications

References 34 publications

Control of plasma properties in capacitively coupled oxygen discharges via the electrical asymmetry effect

Control of plasma properties in capacitively coupled oxygen discharges via the electrical asymmetry effect

Power absorption in electrically asymmetric dual frequency capacitive radio frequency discharges

Effects of gas pressure on 60/13.56 MHz dual-frequency capacitively coupled plasmas

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