Langmuir probe in low temperature, magnetized plasmas: Theory and experimental verification

Koo, Bon Wook; Hershkowitz, N.; Sarfaty, M.

doi:10.1063/1.370873

Cited by 37 publications

(26 citation statements)

References 8 publications

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“…However, the semiconductor industry has accumulated a great deal of experience and knowledge in this area over the past few decades. Here, the procedures outlined by Koo et al 28 and Field et al…”

Section: Theory and Analysismentioning

confidence: 99%

In situ measurements of plasma properties during gas-condensation of Cu nanoparticles

Koten

Voeller

Patterson

et al. 2016

Journal of Applied Physics

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Since the mean, standard deviation, and modality of nanoparticle size distributions can vary greatly between similar input conditions (e.g., power and gas flow rate), plasma diagnostics were carried out in situ using a double-sided, planar Langmuir probe to determine the effect the plasma has on the heating of clusters and their final size distributions. The formation of Cu nanoparticles was analyzed using cluster-plasma physics, which relates the processes of condensation and evaporation to internal plasma properties (e.g., electron temperature and density). Monitoring these plasma properties while depositing Cu nanoparticles with different size distributions revealed a negative correlation between average particle size and electron temperature. Furthermore, the modality of the size distributions also correlated with the modality of the electron energy distributions. It was found that the maximum cluster temperature reached during plasma heating and the material's evaporation point regulates the growth process inside the plasma. In the case of Cu, size distributions with average sizes of 8.2, 17.3, and 24.9 nm in diameter were monitored with the Langmuir probe, and from the measurements made, the cluster temperatures for each deposition were calculated to be 1028, 1009, and 863 K. These values are then compared with the onset evaporation temperature of particles of this size, which was estimated to be 1059, 1068, and 1071 K. Thus, when the cluster temperature is too close to the evaporation temperature, less particle growth occurs, resulting in the formation of smaller particles. V C 2016 AIP Publishing LLC.

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Section: Theory and Analysismentioning

confidence: 99%

In situ measurements of plasma properties during gas-condensation of Cu nanoparticles

Koten

Voeller

Patterson

et al. 2016

Journal of Applied Physics

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“…Moreover, by using the inflexion point method, 15 the plasma or space potential V s can also be evaluated without difficulty. The use of the inflection point method for finding V s was preferred to the usual approach, 3 i.e., that of the intersection point of the tangent lines to the transition and electron saturation regions of the semilogarithmic I e − V plot, because in the presence of a moderate magnetic field the latter method leads to the underestimation of V s . An example of such a dI / dV curve is shown in Fig.…”

Section: A Plasma Potentialmentioning

confidence: 99%

“…The difficulty of such an endeavor increases if the plasma is produced by a high frequency electromagnetic field, 1-4 if external magnetic fields are present, [2][3][4][5][6][7][8][9] or if the studied plasma contains two electron populations. The difficulty of such an endeavor increases if the plasma is produced by a high frequency electromagnetic field, 1-4 if external magnetic fields are present, [2][3][4][5][6][7][8][9] or if the studied plasma contains two electron populations.…”

Section: Introductionmentioning

confidence: 99%

Langmuir probe data analysis for a magnetized inductive radio-frequency discharge

Popescu

Ohtsu

Fujita

2007

Journal of Applied Physics

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Articles you may be interested inCriteria of radio-frequency ring-shaped hollow cathode discharge using H2 and Ar gases for plasma processing J. Appl. Phys. 113, 033302 (2013); 10.1063/1.4776220Investigation of magnetic-pole-enhanced inductively coupled nitrogen-argon plasmas J. Appl. Phys. 112, 063305 (2012); 10.1063/1.4754509Analysis of uncompensated Langmuir probe characteristics in radio-frequency discharges revisited Electrostatic probe diagnostics of a planar-type radio-frequency inductively coupled oxygen plasma Diagnostics of inductively amplified magnetron discharges by optical emission, absorption spectroscopy, and Langmuir probe measurementsThe properties of an inductively coupled argon plasma in a uniform magnetic field, at pressures of the order of 0.1 Pa, in the presence of a weak current-free electric double layer, are measured with a plane Langmuir probe. The static current-voltage probe characteristics, recorded on the symmetry axis of the experimental device, both in the plasma source and in the main chamber of the setup, showed the existence of two electron populations with different temperatures. The axial profiles of plasma parameters, such as the plasma potential and the cold and hot electron temperatures, offered a new insight into such a complex system. However, both the external magnetic field and the two electron populations contribute to the difficulty of calculation of the local plasma density. A method for solving this problem, involving the definition of an effective electron temperature, is also presented.

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“…This fact relates to the temperature minimum. The last term in (24) is then large and changes sign at the minimum, making the graph tilt upwards past it, a feature found in some experiments and displayed in unmagnetized plasmas with two electron temperatures [19,35].…”

Section: Figures 1 Andmentioning

confidence: 83%

New books on physics and related sciences

Zakharova¹

2002

Phys.-Usp.

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The electron-retarding range of the current-voltage characteristic of a flat Langmuir probe perpendicular to a strong magnetic field in a fully ionized plasma is analysed allowing for anomalous (Bohm) cross-field transport and temperature changes in the collection process. With probe size and ion thermal gyroradius comparable, and smaller than the electron mean free path, there is an outer quasineutral region with ion viscosity determinant in allowing nonambipolar parallel and cross flow. A potential overshoot lying either at the base or inside the quasineutral region both makes ions follow Boltzmann's law at negative bias and extends the electron-retarding range to probe bias eφ P ∼ +2T ∞ . Electron heating and cooling occur roughly at positive and negative bias, with a T e -minimum around eφ P ∼ −2T ∞ ; far from the probe heat conduction cools and heats electrons at and radially away from the probe axis, respectively. The potential overshoot with no thermal effects would reduce the electron current I e , making the ln I e versus φ P graph downwards-concave, but cooling further reduces I e substantially, and may tilt the slope upwards past the temperature minimum. The domain of strict validity of our analysis is narrow in case of low ion mass (deuterium), breaking down with the ion Boltzmann law.

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Langmuir probe in low temperature, magnetized plasmas: Theory and experimental verification

Cited by 37 publications

References 8 publications

In situ measurements of plasma properties during gas-condensation of Cu nanoparticles

In situ measurements of plasma properties during gas-condensation of Cu nanoparticles

Langmuir probe data analysis for a magnetized inductive radio-frequency discharge

New books on physics and related sciences

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