An experimental system for symmetric capacitive rf discharge studies

Godyak, Valery; Piejak, R. B.; Alexandrovich, B. M.

doi:10.1063/1.1141370

Cited by 31 publications

(10 citation statements)

References 13 publications

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“…Careful design of the rf discharge experiment can go some way to alleviate some of the problems associated with a Langmuir probe system [ 5 ], but this is of little use to the GEC cell user who must operate the probe system in an existing chamber. Therefore, we will present here details of the rf probe system which has been used over the past decade at Dublin City University (DCU) and has recently been successfully applied to a number of GEC cells.…”

Section: Introductionmentioning

confidence: 99%

Langmuir Probe Measurements in the Gaseous Electronics Conference Rf Reference Cell

Hopkins¹

1995

J. Res. Natl. Inst. Stand. Technol.

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The use of a Langmuir probe system in two GEC cells is reviewed. The major problems associated with probe diagnostics in a GEC cell are outlined and discussed. While the data base is still insufficient to give definitive values for many parameters, a number of standard measurements are put forward. The plasma density in argon is 9×109 cm−3 (±20 %) at an applied rf voltage of 250 V (500 V peak to peak) and a gas pressure of 13.3 Pa (100 mTorr). The electron density scales linearly with applied voltage. The plasma to ground sheath resistance is shown to be very important with a value of 810 Ω in argon at a pressure of 13.3 Pa (100 mTorr) and discharge current of 0.1 A. The value of plasma to ground resistance scales inversely with discharge current and sublinear with pressure. Two standard features in the electron energy distribution function (EEDF) have been proposed as a test of the ability of a probe system to resolve features, first, the transition from a low temperature (<1 eV) bi-Maxwellian distribution to a Druyveysten distribution (3 eV) at 13.3 Pa (100 mTorr) in argon, and the “hole” in the EEDF at 2 eV to 4 eV in nitrogen plasmas.

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Section: Introductionmentioning

confidence: 99%

Langmuir Probe Measurements in the Gaseous Electronics Conference Rf Reference Cell

Hopkins¹

1995

J. Res. Natl. Inst. Stand. Technol.

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“…There are several symmetric CCP setups in the literature with different approaches how to confine the plasma without breaking symmetry. In most cases, the plasma is confined by a dielectric cylinder wall [25,26,32,[35][36][37][38][39]. In our case, it is of high importance that the plasma faces only one surface material in order to avoid surface effects from a second dielectric material.…”

Section: Methodsmentioning

confidence: 96%

A computationally assisted technique to measure material-specific surface coefficients in capacitively coupled plasmas based on characteristics of the ion flux-energy distribution function

Schulze

Benedikt

2022

Plasma Sources Sci. Technol.

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We present a new method for the determination of surface coefficients, more specifically the effective ion-induced secondary electron yield, γeff, and the effective elastic electron reflection coefficient, reff, by means of a synergistic combination of energy-selective mass spectrometry measurements and numerical Particle-in-cell/Monte Carlo collisions simulations of the ion flux-energy distribution function (IEDF) in a symmetric capacitively coupled plasma (CCP). In particular, we analyze the bimodal peak structure of the IEDF, which is caused by ions crossing the sheath without collisions. The position and width of this structure on the energy scale are defined by the time-averaged sheath potential and the ion transit time through the sheath, respectively. We find that both characteristics are differently influenced by γeff and reff. The ion-induced secondary electrons are accelerated in the large sheath potential and mainly influence the plasma density, sheath width and, consequently, the ion transit time and in this way the bimodal peak separation. Electron reflection from the electrodes acts mainly at times of sheath collapse, where low energy electrons can reach the surfaces. Their contribution to the plasma density increase is small, however, their longer residence time in the vicinity of the electrodes modifies the space charge density and the potential gradient. Additionally, the charge balance at the electrode requires an incident electron flux that is correlated to the emitted ion induced secondary electron flux, which is realized by a change of the electron repelling sheath voltage. As a consequence, the electron reflection coefficient mainly influences the sheath potential and, hence, the position of the bimodal peak structure. These effects allow the simultaneous in-situ determination of both surface parameters. The parameter values determined for stainless steel and Al2O3 surfaces are in good agreement with literature data. Our method opens a straightforward way of obtaining γeff and reff under realistic plasma conditions.

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“…The CCP system, usually the geometry of RF discharge is very simple because design with two parallel electrodes. There are two type of CCPs RF discharge, symmetric discharge include two identical electrodes [5,6], whilst in asymmetric discharge systems the plasma formed between two unequal electrodes area, later create a dc voltage appears as a result for the different in electron and ion mobility, this attributes to the different mass between them. Some research study the influence of the geometry design on the characteristics of CCP discharge with different gases as well as observed by using the different electrodes area ratio which play important role in dcself bias [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Influence of electrodes area ratios and the discharge volume in RF capacitively coupled plasma

Ahmad¹

2019

IJP

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Experimental results on harmonic distortions in 13.56 MHz RF Argon glow discharge using different grounded electrodes areas and electrodes spacing are presented. The experiment is carried out at four pressure values. RF power values used are between 20 and 90 watts. The results indicate significant increase in distortions at two specific values of the cone angle enclosing the two electrodes within its geometrical volume. The computation of the cone head angle gave the symmetry discharge or asymmetry as well as when the angle is small the condition is near symmetry discharge associated with decrease in the nonlinearity.

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An experimental system for symmetric capacitive rf discharge studies

Cited by 31 publications

References 13 publications

Langmuir Probe Measurements in the Gaseous Electronics Conference Rf Reference Cell

Langmuir Probe Measurements in the Gaseous Electronics Conference Rf Reference Cell

A computationally assisted technique to measure material-specific surface coefficients in capacitively coupled plasmas based on characteristics of the ion flux-energy distribution function

Influence of electrodes area ratios and the discharge volume in RF capacitively coupled plasma

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