Magnetical asymmetric effect in geometrically and electrically symmetric capacitively coupled plasma

Yang, Shali; Zhang, Ya; Wang, Hongyu; Cui, Jianwei; Jiang, Wei

doi:10.1002/ppap.201700087

Cited by 37 publications

(38 citation statements)

References 46 publications

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“…Moreover, the ion flux can be adjusted in this way [20]. Oberberg et al [21] also found that tuning such axially non-uniform magnetic fields in low pressure CCPs allows to control the self-excitation of the plasma series resonance (PSR) and Non-Linear Electron Resonance Heating (NERH) in space and time due to the magnetic control of the plasma symmetry [22,23].…”

Section: Introductionmentioning

confidence: 99%

Electron power absorption dynamics in magnetized capacitively coupled radio frequency oxygen discharges

Wang

Wen

Hartmann

et al. 2020

Plasma Sources Sci. Technol.

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The influence of a uniform magnetic field parallel to the electrodes on radio frequency capacitively coupled oxygen discharges driven at 13.56 MHz at a pressure of 100 mTorr is investigated by one-dimensional Particle-in-Cell/Monte Carlo collision (1D PIC/MCC) simulations. Increasing the magnetic field from 0 to 200 G is found to result in a drastic enhancement of the electron and the O + 2 ion density due to the enhanced confinement of electrons by the magnetic field. The time and space averaged O − ion density, however, is found to remain almost constant, since both the dissociative electron attachment (production channel of O − ) and the associative electron detachment rate due to the collisions of negative ions with oxygen metastables (main loss channel of O − ) are enhanced simultaneously. This is understood based on a detailed analysis of the spatio-temporal electron dynamics.The nearly constant O − density in conjunction with the increased electron density causes a significant reduction of the electronegativity and a pronounced change of the electron power absorption dynamics as a function of the externally applied magnetic field. While at low magnetic fields the discharge is operated in the electronegative Drift-Ambipolar (DA) mode, a transition to the electropositive α-mode is induced by increasing the magnetic field. Meanwhile, a strong electric field reversal is generated near each electrode during the local sheath collapse at high magnetic fields, which locally enhances the electron power absorption. A model of the electric field generation reveals that the reversed electric field is caused by the reduction of the electron flux to the electrodes due to their trapping by the magnetic field.The consequent changes of the plasma properties are expected to affect the applications of such discharges in etching, deposition and other semiconductor processes.

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Section: Introductionmentioning

confidence: 99%

Electron power absorption dynamics in magnetized capacitively coupled radio frequency oxygen discharges

Wang

Wen

Hartmann

et al. 2020

Plasma Sources Sci. Technol.

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“…In Ref. 34 35,36 have used an asymmetric magnetic field with variable gradients to create asymmetry in the configuration of a CCP device. Their particle simulation studies show that the magnetic field asymmetry provides a means of independently controlling the ion flux and ion energy.…”

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confidence: 99%

“…Other recent studies devoted to CCP operation in the presence of an external magnetic field 26,27,34 , have explored somewhat different effects. S. Yang et al 35,36 have used an asymmetric magnetic field with variable gradients to create asymmetry in the configuration of a CCP device. Their particle simulation studies show that the magnetic field asymmetry provides a means of independently controlling the ion flux and ion energy.…”

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confidence: 99%

Spatial symmetry breaking in single-frequency CCP discharge with transverse magnetic field

et al. 2018

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An independent control of the flux and energy of ions impacting on an object immersed in a plasma is often desirable for many industrial processes such as microelectronics manufacturing. We demonstrate that a simultaneous control of these quantities is possible by a suitable choice of a static magnetic field applied parallel to the plane electrodes in a standard single frequency capacitively coupled plasma device. Our particle-in-cell simulations show a 60% reduction in the sheath width (that improves control of ion energy) and a four fold increase in the ion flux at the electrode as a consequence of the altered ion and electron dynamics due to the ambient magnetic field. A detailed analysis of the particle dynamics is presented and the optimized operating parameters of the device are discussed. The present technique offers a simple and attractive alternative to conventional dual frequency based devices that often suffer from undesirable limitations arising from frequency coupling and electromagnetic effects.

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“…The method has frequently been applied in studies of dual-frequency RF discharges [62,63], plasma sources operated under the conditions where electrical asymmetry develops [64,65], as well as in investigations of discharges driven by Tailored Voltage Waveforms [66][67][68][69]. Related to this, the effects of various asymmetries, like those created by a magnetic field [70], by unequal secondary electron yields at the two electrodes [71,72] have been investigated, as well as the interplay between geometrical and electrical asymmetry effects in CCPs [6,73]. A similarity law and the frequency scaling properties of CCPs were recently reported [74].…”

Section: Introductionmentioning

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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Magnetical asymmetric effect in geometrically and electrically symmetric capacitively coupled plasma

Cited by 37 publications

References 46 publications

Electron power absorption dynamics in magnetized capacitively coupled radio frequency oxygen discharges

Electron power absorption dynamics in magnetized capacitively coupled radio frequency oxygen discharges

Spatial symmetry breaking in single-frequency CCP discharge with transverse magnetic field

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

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