A simple analysis on the abnormal behavior of the argon metastable density in an inductively coupled Ar plasma

Park, Min; Chang, Hong‐Young; You, S. J.; Kim, Jung-Hyung; Seong, Dong-Ook; Shin, Young-Han

doi:10.1016/j.tsf.2010.03.135

Cited by 9 publications

(7 citation statements)

References 16 publications

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“…This suggestion is quite clear but limited to diffusion dominated metastable condition. On the other hand, Park et al 40 suggested that the anomalous a) Electronic mail: sjyou@kriss.re.kr.…”

Section: Introductionmentioning

confidence: 99%

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge

Park¹,

Chang²,

You³

et al. 2011

Physics of Plasmas

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Section: Introductionmentioning

confidence: 99%

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge

Park¹,

Chang²,

You³

et al. 2011

Physics of Plasmas

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“…[ 12,13,30 ] Higher excited 2 p states (2 p 10 through 2 p 1 ) are often omitted from argon plasma models [ 9,17,31–34 ] ; however, they may also be grouped together with the metastable species [ 35–37 ] or represented as separate grouped processes. [ 30,38–41 ] The wide variability in choice of grouping, along with the cross‐section data chosen to represent these grouped processes, makes it difficult for readers to understand exactly which processes are represented in any given model. This paper attempts to clearly define the choices of electron impact process aggregation and cross‐section data to develop a well‐posed argon plasma model that may be easily reproduced by other researchers.…”

Section: Methodsmentioning

confidence: 99%

“…The threshold energies for these grouped processes are listed in Table 2, and they were taken from the lowest threshold energy in the group. Superelastic collisions with electronically excited argon species are omitted in References [17,35,37,38] and included (typically for metastable species only) in References [12,13,30–33,36,39–41]. In the current study, superelastic collisions with excited species are only included for the metastable Ar m , using the principle of detailed balancing.…”

Section: Methodsmentioning

confidence: 99%

Continuum modelling of an asymmetric CCRF argon plasma reactor: Influence of higher excited states and sensitivity to model parameters

Baldry

Haidar

Akhavan

et al. 2021

Plasma Processes & Polymers

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Precise control of capacitively coupled radiofrequency (CCRF) plasma reactors is required to achieve desired outcomes in surface functionalisation and material synthesis processes. This necessitates detailed mapping of the large process parameter space and a thorough understanding of spatial and temporal variations of the plasma throughout the reactor. These goals can only feasibly be achieved with accurate numerical modelling. Previous numerical studies of CCRF discharges have implemented a range of simplifying assumptions to improve numerical tractability, such as small electrode spacing, radial uniformity, fewer active species and simplified boundary conditions, while neglecting self‐bias formation. Although this approach is useful in developing the methodology for continuum plasma modelling, it poses challenges for direct comparison with experimental data and for understanding the behaviour of plasma processes employed in the surface treatment of large, complex objects, or the synthesis of nanoparticles. Here we report the development of a two‐dimensional axisymmetric continuum model for a CCRF reactor with a pure argon 13.56‐MHz discharge using the finite element method. The large electrode spacing and reactor design result in two distinct discharge regions and the formation of a strong DC self‐bias on the powered electrode. The plasma discharge is studied as the pressure is varied from 0.1 to 0.3 Torr, over the radiofrequency input power range of 25–100 W, which leads to consistent enhancements of the electron density and self‐bias. The impact of the electron energy distribution function (EEDF) on the discharge is assessed, with the assumption of a Druyvesteyn EEDF resulting in a bulk electron density and temperature of 3.4 × 1015 m−3 and 3.3 eV, respectively, compared with 8.1 × 1015 m−3 and 1.9 eV in the Maxwellian case. The asymmetric power distribution throughout the reactor is quantified to build a reduced domain model with a lower computational cost. The effect of an electrically floating parallel plate electrode is assessed, resulting in a 42% higher bulk plasma potential as compared with the grounded case. The inclusion of resonant and 2p excited states of argon is shown to have a major impact on the discharge dynamics, leading to an order of magnitude reduction in bulk electron density. This study proposes a robust numerical model of a CCRF argon plasma discharge to facilitate future simulations of more complex discharges with important implications in plasma surface engineering and synthesis of materials.

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“…[4][5][6][7][8][9][10][11][12][13][14][15] However, the results have been controversial: Some groups have reported that the Ar metastable density increases or is almost constant with increasing electron density, 9,11,13 whereas other groups have reported that the Ar metastable density decreases with the electron density. 8,10 This controversial problem was resolved by discovering the anomalous evolution of argon metastable density with electron density (discharge power) included both trends.…”

Section: Introductionmentioning

confidence: 99%

“…5 To explain the physics behind the abnormal evolution, Park et al suggested that it could be due to the evolution of the electron energy distribution functions (EEDFs) during the mode transition (the evolution of an EEDF from a biMaxwellian to a Maxwellian). 6 Later, by virtue of an adequate physical explanation based on a simple global model, both evolutions of the metastable density were comprehensively understood as part of the abnormal evolution occurring at low-and high-density regimes, respectively. This model showed that the main mechanism of the population and depopulation of the Argon metastable atoms can be significantly changed depending on the electron density and that the anomalous evolution can result from the competition between the mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Normal and abnormal evolution of argon metastable density in high-density plasmas

2015

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A controversial problem on the evolution of Ar metastable density as a function of electron density (increasing trend versus decreasing trend) was resolved by discovering the anomalous evolution of the argon metastable density with increasing electron density (discharge power), including both trends of the metastable density [Daltrini et al., Appl. Phys. Lett. 92, 061504 (2008)]. Later, by virtue of an adequate physical explanation based on a simple global model, both evolutions of the metastable density were comprehensively understood as part of the abnormal evolution occurring at low-and high-density regimes, respectively, and thus the physics behind the metastable evolution has seemed to be clearly disclosed. In this study, however, a remarkable result for the metastable density behavior with increasing electron density was observed: even in the same electron density regime, there are both normal and abnormal evolutions of metastable-state density with electron density depending on the measurement position: The metastable density increases with increasing electron density at a position far from the inductively coupled plasma antenna but decreases at a position close to the antenna. The effect of electron temperature, which is spatially nonuniform in the plasma, on the electron population and depopulation processes of Argon metastable atoms with increasing electron density is a clue to understanding the results. The calculated results of the global model, including multistep ionization for the argon metastable state and measured electron temperature, are in a good agreement with the experimental results. V C 2015 AIP Publishing LLC. [http://dx.

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A simple analysis on the abnormal behavior of the argon metastable density in an inductively coupled Ar plasma

Cited by 9 publications

References 16 publications

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge

Continuum modelling of an asymmetric CCRF argon plasma reactor: Influence of higher excited states and sensitivity to model parameters

Normal and abnormal evolution of argon metastable density in high-density plasmas

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