Selective modulation of plasma parameters in an atmospheric dielectric barrier discharge driven by sawtooth-type tailored voltage waveforms

Zhang, Z.; Nie, Qiulin; Wang, Z.; Lim, J. W. M.

doi:10.1063/5.0006078

Cited by 4 publications

(3 citation statements)

References 45 publications

(42 reference statements)

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“…Note that during the up chirp, the RF period decreases as the frequency increases, the positive bias time of the voltage waveform is longer than the negative bias, and vice versa during the down chirp. It means that the asymmetry of the waveform may cause the EAE, which is reported in the literature before [16][17][18][19][20][21], but only minimal self-bias (−2 V to +4 V, about 1% of the power source amplitude) is observed in our presimulations. This may be due to the tailored voltage waveforms with multiple harmonics having the same asymmetry in each RF period in the traditional EAE.…”

Section: Electron Kineticssupporting

confidence: 53%

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Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

Wang,

Zhou,

Chen

et al. 2024

Plasma Sources Sci. Technol.

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Capacitively coupled plasma (CCP) is widely used in plasma etching and deposition processes because of its low cost, simple structure, and easy generation of a uniform plasma in large areas. Conventional CCPs are operated under a fixed frequency power source; however, CCPs driven by a variable frequency power source are poorly understood. In this paper, numerical simulations of CCPs driven by frequency modulated (FM) radio frequency (RF) sources within the frequency range of 2 MHz to 18 MHz are carried out with a Particle-in-Cell/Monte Carlo collision model. Our research indicates that the CCP driven by an FM RF source can maintain a stable glow discharge and form a time-dependent plasma. Plasma density, electron and ion current, energy and heating rate, ion flux, and energy on the electrodes fluctuate consistently with the FM period. The electron and ion energy distribution function can also be modulated by the frequency variation of the FM source. A multi-peak structure that varies and shifts with frequency variation is observed in the ion energy distribution function. In addition, by fixing the chirp period while varying the start or end frequency of the chirp signal (start frequency from 0.4 to 6 MHz, or end frequency from 18 to 48 MHz), effective modulations can be produced on the electron density, electron energy, and the shape of the EEPF and IEDF.

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Section: Electron Kineticssupporting

confidence: 53%

“…The electrical asymmetry effect (EAE) can also be used to optimize CCP discharge. It has been proposed that by applying an asymmetric voltage waveform and modifying the parameters of the harmonic component, the ion flux and the ion energy can be decoupled in an extensive parameter range [16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

Wang,

Zhou,

Chen

et al. 2024

Plasma Sources Sci. Technol.

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“…In addition to the filamentary and patterned discharge regimes [16,17], homogenous discharges in Townsend, glow or RF α and γ modes are also used [18][19][20][21][22], including for thin film deposition [3,15]. New excitation waveforms for homogenous discharges have also been proposed, including dual-frequency [23][24][25][26], frequency-shift keying [27,28] or sawtooth tailored discharges [29]. In low-frequency (LF) plasmas, metastable states play a major role in maintaining the discharge in a homogeneous regime [30].…”

Section: Introductionmentioning

confidence: 99%

Role of excimer formation and induced photoemission on the Ar metastable kinetics in atmospheric pressure Ar–NH₃ dielectric barrier discharges

Robert¹,

Hagelaar²,

Sadeghi³

et al. 2022

Plasma Sources Sci. Technol.

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Tunable diode laser absorption spectroscopy was used to record the space-and time-resolved number density of argon metastable atoms, Ar(1s3) (Paschen notation), in plane-to-plane dielectric barrier discharges operated in a Penning Ar-NH3 mixture at atmospheric pressure. In both low-frequency (LF 650 V, 50 kHz) discharges and dual LF-radiofrequency (RF 190 V, 5 MHz) discharges operated in α-γ mode, the density of Ar(1s3) revealed a single peak per half-period of the LF voltage, with rise and decay times in the sub-microsecond time scale. These results were compared to the predictions of a 1D fluid model based on continuity and momentum equations for electrons, argon ions (Ar+ and Ar2 +) and excited argon 1s atoms as well electron energy balance equation. Using the scheme commonly reported for Ar-based dielectric barrier discharges in the homogeneous regime, the Ar metastable kinetics exhibited much slower rise and decay times than the ones seen in the experiments. The model was thus refined by considering the fast creation of Ar2 * excimers through 3-body reactions involving Ar(1s) atoms and the rapid loss of Ar2 *by vacuum ultraviolet light emission. In optically thin media for such photons, they can readily reach the dielectric barriers of the DBD electrodes and induce secondary electron emission. It is shown that Ar2 * and photoemission play a significant role not only on the Ar metastable kinetics, but also on the dominant ionization pathways and possible α-γ transition in dual frequency RF-LF discharges.

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Numerical investigation of the directional control of electron density and gas temperature in atmospheric pressure dielectric barrier discharge by using low- and high-frequency coupling modulation

et al. 2021

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Dielectric barrier discharges (DBDs) are commonly used as efficient sources of large volume diffuse plasmas with moderate temperature and plenty of reactive particles, but the synergistic linkage of some key plasma parameters in single frequency driven systems sometimes limits their application fields and accessible operating ranges. The discrete control of certain key plasma parameters by multi-frequency, i.e., dual frequency (DF), voltage waveform excitations is of increasing requirement and importance for both application-focused and fundamental studies on DBD plasma. In this paper, a significant nonlinear coupling modulation of the discharge evolution process and characteristics caused by the HF oscillation of the high-frequency component in the DF DBD system is observed and investigated, which provides a simple and efficient approach to realize the independent control of the target key plasma parameters such as gas temperature and electron density. Based on a one-dimensional fluid model with semi-kinetics treatment, numerical studies of the tiny high frequency component on the properties modulation of atmospheric DF DBD are reported. The driving voltage waveform is characterized by a 50 kHz fundamental sinusoidal low-frequency signal superimposing a small amount of 2 MHz high-frequency signal [HF component changing from 0 to 100 V with a low-frequency (LF) component fixed at 1 kV as a constant], and the effects of the high-frequency voltage amplitude and phase shift on the discharge characteristics, sheath dynamics, impact ionization of electrons, and key plasma parameters are investigated. Particularly, the effects of phase modulation on the discharge evolution and characteristics for DF DBDs are discussed and revealed. The results have demonstrated that a slight and proper parameter variation of the high-frequency oscillation can provide a high electron seed density, and trap electrons within the sheath, thus achieving required plasma parameters. The sheath dynamics can be effectively modulated by tuning the phase shift, which enables a possible alternative approach to optimize the independent control of the key plasma parameters under atmospheric pressure.

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Selective modulation of plasma parameters in an atmospheric dielectric barrier discharge driven by sawtooth-type tailored voltage waveforms

Cited by 4 publications

References 45 publications

Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

Role of excimer formation and induced photoemission on the Ar metastable kinetics in atmospheric pressure Ar–NH₃ dielectric barrier discharges

Numerical investigation of the directional control of electron density and gas temperature in atmospheric pressure dielectric barrier discharge by using low- and high-frequency coupling modulation

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Selective modulation of plasma parameters in an atmospheric dielectric barrier discharge driven by sawtooth-type tailored voltage waveforms

Cited by 4 publications

References 45 publications

Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

Numerical characterization of capacitively coupled plasma driven by tailored frequency modulated radio frequency source

Role of excimer formation and induced photoemission on the Ar metastable kinetics in atmospheric pressure Ar–NH3 dielectric barrier discharges

Numerical investigation of the directional control of electron density and gas temperature in atmospheric pressure dielectric barrier discharge by using low- and high-frequency coupling modulation

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Role of excimer formation and induced photoemission on the Ar metastable kinetics in atmospheric pressure Ar–NH₃ dielectric barrier discharges