Material dependent modeling of secondary electron emission coefficients and its effects on PIC/MCC simulation results of capacitive RF plasmas

Daksha, Manaswi; Derzsi, Aranka; Zaka-ul-Islam, M.; Schulenberg, D.; Berger, Birk; Donkó, Zoltán; Schulze, Julian

doi:10.1088/1361-6595/ab094f

Cited by 48 publications

(49 citation statements)

References 81 publications

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“…46 This approach allows to derive so-called "apparent" or "effective" γ* SEECs. 47,48 Alternatively, SEECs determined in situ by computationally assisted spectroscopic techniques 50 or SEECs obtained based on theoretical models of the SEE 51 can be used in the simulations of CCPs.…”

Section: Introductionmentioning

confidence: 99%

Heavy-particle induced secondary electrons in capacitive radio frequency discharges driven by tailored voltage waveforms

Derzsi

Horvath

Korolov

et al. 2019

Journal of Applied Physics

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Particle-in-Cell/Monte Carlo Collision simulations are performed to investigate the effects of heavy-particle induced secondary electrons (SEs) on the ionization dynamics and on the control of ion properties at the electrodes in geometrically symmetric capacitively coupled argon discharges driven by tailored voltage waveforms. The driving voltage waveform is composed of a maximum of four (1 N 4) consecutive harmonics of the fundamental frequency of 13.56 MHz and is tailored by adjusting the identical phases of the even harmonics, θ. The simulations are carried out at neutral gas pressures of 3 Pa (nearly collisionless low-pressure regime) and 100 Pa (collisional high-pressure regime). Different approaches are used in the simulations to describe the secondary electron emission (SEE) at the electrodes: we adopt (i) constant ion-induced secondary electron emission coefficients (SEECs), γ, and (ii) realistic, energy-dependent SE yields for ions and fast neutrals. The mean ion energy at the electrodes, hE i i, can be controlled by θ at both pressures, for both approaches adopted to describe the SEE in the simulations. At a low pressure of 3 Pa, we obtain largely different dependencies of the ion flux at the electrodes, Γ i , on θ, depending on the value of the γ-coefficient. For γ ¼ 0:2, Γ i remains nearly constant as a function of θ, independently of the choice of N, i.e., the mean ion energy can be controlled separately from the ion flux by adjusting θ. However, for values of γ different from 0.2, the quality of the separate control of the ion properties changes significantly. At a high pressure of 100 Pa, independently of the choice of γ, for a given N ! 2, the ion flux varies as a function of θ. At both pressures, the surface conditions affect the plasma parameters and the quality of the separate control of ion properties at the electrodes. Adopting realistic, energy-dependent SE yields for heavy particles in the simulations can lead to significantly different results compared to those obtained by assuming constant SEECs.

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Section: Introductionmentioning

confidence: 99%

Heavy-particle induced secondary electrons in capacitive radio frequency discharges driven by tailored voltage waveforms

Derzsi

Horvath

Korolov

et al. 2019

Journal of Applied Physics

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“…The new particles created at the surfaces (e.g. secondary electrons) can be added to the simulation, according to the surface model [55,75,76,[116][117][118][119][120][121]. In the present work, we use a very simple surface model: all particles reaching the electrodes are absorbed and no particles are emitted from the electrodes.…”

Section: Adding/removing Particles At the Boundariesmentioning

confidence: 99%

eduPIC: an introductory particle based code for radio-frequency plasma simulation

Donko,

Derzsi,

Vass

et al. 2021

Preprint

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Particle based simulations are indispensable tools for numerical studies of charged particle swarms and low-temperature plasma sources. The main advantage of such approaches is that they do not require any assumptions regarding the shape of the particle Velocity/Energy Distribution Function (VDF/EDF), but provide these basic quantities of kinetic theory as a result of the computations. Additionally, they can provide, e.g., transport coefficients, under arbitrary time and space dependence of the electric/magnetic fields. For the self-consistent description of various plasma sources operated in the low-pressure (nonlocal, kinetic) regime, the Particle-In-Cell simulation approach, combined with the Monte Carlo treatment of collision processes (PIC/MCC), has become an important tool during the past decades. In particular, for Radio-Frequency (RF) Capacitively Coupled Plasma (CCP) systems PIC/MCC is perhaps the primary simulation tool these days. This approach is able to describe discharges over a wide range of operating conditions, and has largely contributed to the understanding of the physics of CCPs operating in various gases and their mixtures, in chambers with simple and complicated geometries, driven by single-and multi-frequency (tailored) waveforms. PIC/MCC simulation codes have been developed and maintained by many research groups, some of these codes are available to the community as freeware resources. While this computational approach has already been present for a number of decades, the rapid evolution of the computing infrastructure makes it increasingly more popular and accessible, as simulations of simple systems can be executed now on personal computers or laptops. During the past few years we have experienced an increasing interest in lectures and courses dealing with the basics of particle simulations, including the PIC/MCC technique. In a response to this, this paper (i) provides a tutorial on the physical basis and the algorithms of the PIC/MCC technique and (ii) presents a basic (spatially one-dimensional) electrostatic PIC/MCC simulation code, whose source is made freely available in various programming languages. We share the code in C/C++ versions, as well as in a version written in Rust, which is a rapidly emerging computational language. Our code intends to be a "starting tool" for those who are interested in learning the details of the PIC/MCC technique and would like to develop the "skeleton" code further, for their research purposes. Following the description of the physical basis and the algorithms used in the code, a few examples of results obtained with this code for single-and dual-frequency CCPs in argon are also given.

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“…Further, the plasma itself can be strongly affected by plasma‐surface‐interactions like secondary electron emission. [ 19–24 ] Thus, usage of the large surface‐to‐volume ratio of t‐ZnO as electrode material could enhance plasma properties, especially, for microplasmas, where the surface‐to‐volume ratio is already quite large. [ 25–27 ]…”

Section: Introductionmentioning

confidence: 99%

“…Further, the plasma itself can be strongly affected by plasma-surface-interactions like secondary electron emission. [19][20][21][22][23][24] Thus, usage of the large surface-to-volume ratio of t-ZnO as electrode material could enhance plasma properties, especially, for microplasmas, where the surface-to-volume ratio is already quite large. [25][26][27] Other examples, like plasma catalysis [28][29][30][31] , also showcase applications where the penetration of plasma species into the highly porous t-ZnO material is favorable if not necessary.…”

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confidence: 99%

On the plasma permeability of highly porous ceramic framework materials using polymers as marker materials

Marxen

Hansen

Reimers

et al. 2022

Plasma Processes & Polymers

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Highly porous framework materials are of large interest due to their broad potential for application, for example, as sensors or catalysts. A new approach is presented to investigate, how deep plasma species can penetrate such materials. For this purpose, a polymer (ethylene propylene diene monomere rubber) is used as marker material and covered with the porous material during plasma exposure. Water contact‐angle and X‐ray photoelectron spectroscopy measurements are used to identify changes in the polymer surface, originating from the interaction of plasma species with the polymer. The method is demonstrated by studying the plasma permeability of tetrapodal zinc oxide framework materials with a porosity of about 90% in an oxygen low‐pressure capacitively coupled plasma. Significant differences in the penetration depth ranging from roughly 1.6–4 mm are found for different densities of the material and different treatment conditions.

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Material dependent modeling of secondary electron emission coefficients and its effects on PIC/MCC simulation results of capacitive RF plasmas

Cited by 48 publications

References 81 publications

Heavy-particle induced secondary electrons in capacitive radio frequency discharges driven by tailored voltage waveforms

Heavy-particle induced secondary electrons in capacitive radio frequency discharges driven by tailored voltage waveforms

eduPIC: an introductory particle based code for radio-frequency plasma simulation

On the plasma permeability of highly porous ceramic framework materials using polymers as marker materials

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