Verification of collisionless sheath model of capacitive rf discharges by particle-in-cell simulations

Wang, Ying; Lieberman, M. A.; Wu, Alan; Verboncoeur, John P.

doi:10.1063/1.3620983

Cited by 9 publications

(5 citation statements)

References 20 publications

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“…where E i is the mean ion kinetic energy for ions hitting the electrode (the median of the IED). These indicate that the Cl + 2 and Cl + ions travel through an almost collisionless sheath at low pressures (5 and 10 mTorr) according to the verification in an argon discharge by Wang et al [82,87]. A similar IED profile indicating collisionless sheath has also been observed for O + 2 and O + ions in an oxygen discharge at 3 mTorr by Kratzer et al [88].…”

Section: P (Mtorr) P Abs (W) Nsupporting

confidence: 65%

“…At low pressures, the profile for Cl + 2 ions is cosine-like or parabolic since Cl + 2 ions are lost mainly due to diffusion to the walls [6], which is similar to the electropositive argon discharge [82]. As the pressure increases, the recombination between Cl + 2 and Cl − ions becomes the major loss mechanism for Cl + 2 ions and the ionization and attachment reaction rates become uniform in the bulk region.…”

Section: P (Mtorr) P Abs (W) Nmentioning

confidence: 92%

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A particle-in-cell/Monte Carlo simulation of a capacitively coupled chlorine discharge

Huang

Guðmundsson

2013

Plasma Sources Sci. Technol.

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Here we demonstrate the oopd1 (object-oriented plasma device for one dimension) particle-in-cell/Monte Carlo simulation tool for a capacitively coupled chlorine discharge with a comprehensive reaction set. We apply a hybrid approach where a global model determines the dissociation fraction of the discharge. The simulation results are compared with available experimental measurements and good agreement is achieved. We explore a typical capacitively coupled chlorine discharge using oopd1 and obtain key plasma parameters, including particle density, effective electron temperature, electron energy probability function and ion energy and angular distributions for both Cl + and Cl + 2 ions. The dependence of the plasma parameters on the discharge pressure is systematically investigated. As the pressure increases from 5 to 100 mTorr, the heating mechanism evolves from both stochastic and Ohmic heating to predominantly Ohmic heating and the electron heating outweighs the ion heating at high pressures. Also, the density profile for Cl + 2 and Cl − ions becomes flat in the bulk region and the electronegativity increases with increasing pressure. The creation of Cl + ions in the sheath region is mainly due to conversion from Cl + 2 ions to Cl + ions through non-resonant charge exchange, while in the bulk region the creation of Cl + ions is mainly ascribed to electron impact ionization processes.

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Section: P (Mtorr) P Abs (W) Nsupporting

confidence: 65%

Section: P (Mtorr) P Abs (W) Nmentioning

confidence: 92%

A particle-in-cell/Monte Carlo simulation of a capacitively coupled chlorine discharge

Huang

Guðmundsson

2013

Plasma Sources Sci. Technol.

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“…Such models also form indispensible tools in plasmas with very complex chemistries, where fluid or kinetic simulations are either too time consuming to perform, or too difficult to extract useful parameter trends. Global models have been used to predict the behavior of many different types of plasma discharges, including capacitively coupled plasmas (CCPs) [6][7][8][9][10][11][12], inductively coupled plasmas (ICPs) [13][14][15][16][17][18], helicon [19,20] and microwave [21] discharges, plasma thrusters such as ion engines [22,23], and with many different gases (including gas mixtures) [24][25][26][27] in these discharges.…”

Section: Introductionmentioning

confidence: 99%

Edge-to-center density ratios in low-temperature plasmas

Lafleur¹,

Chabert²

2015

Plasma Sources Sci. Technol.

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The ion flux leaving a plasma at a boundary can be given by: i = h L n 0 u B , where n 0 is the maximum central plasma density, u B is the Bohm velocity, and h L is the sheath edge-to-center plasma density ratio. Such h L factors have become synonymous with global modeling of plasma discharges, where they play a vital role in the prediction of plasma losses to bounding surfaces. By performing one-dimensional (1D) particle-in-cell simulations of inductively and capacitively coupled plasmas (ICPs and CCPs) over a wide pressure range, we explicitly test the validity of standard heuristic formulae commonly used to estimate h L . The ICP simulation results are found to be in very good agreement, while a large discrepancy is present for the CCP results at high pressures. The onset of this discrepancy is found to be correlated with the bulk-to-sheath edge ionization transition that occurs in CCPs at high pressures. Consequently, global models will strongly underestimate plasma losses in this regime.

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“…Analytical collisional sheath models with charge exchange collisions were developed [13,14]. A global model for capacitive discharges in the collisionless sheath model was proposed to understand bimodal for IED of single frequency capacitive discharge [15].…”

Section: Introductionmentioning

confidence: 99%

The Influence of Ion Energy Distribution for Multiple Frequencies Driven

Zhou

Wang

Kong

2013

AMR

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The voltages, resonant waves and frequencies how to influence on the ion energy distributions (IEDs) from multiple frequencies driven in capacitive discharges, it is important to analyze these phenomenon and mechanism in order to control the microelectronic processes of integrated circuit and develop the base theories of plasma physics. We focused on the function of the ion energy distributions under high and low frequencies (dual frequency) drive in capacitive discharges, we derived a model of computation of the multiple frequencies driven IEDs from analyzing theories. The model can analyze and predict the IEDs under different high and low frequencies driven, the results from the model are in good agreement with these important data from public publish.

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Verification of collisionless sheath model of capacitive rf discharges by particle-in-cell simulations

Cited by 9 publications

References 20 publications

A particle-in-cell/Monte Carlo simulation of a capacitively coupled chlorine discharge

A particle-in-cell/Monte Carlo simulation of a capacitively coupled chlorine discharge

Edge-to-center density ratios in low-temperature plasmas

The Influence of Ion Energy Distribution for Multiple Frequencies Driven

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