Investigation of absolute atomic fluorine density in a capacitively coupled SF6/O2/Ar and SF6/Ar discharge

Kechkar, S; Babu, Sharath; Swift, P.; Gaman, Cezar; Daniels, Stephen; Turner, M. M.

doi:10.1088/0963-0252/23/6/065029

Cited by 10 publications

(12 citation statements)

References 56 publications

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“…Ar N e С ( ) varies considerably with T e only when T e < 4 eV. In the case of fluorine atoms the energy difference of emitting F and Ar states is only ~1 eV and coefficient T Ar F e actinometry for these atoms has been studied, as a rule, by comparing its results with those of other, more direct diagnostics, such as VUV absorption spectroscopy (VUVAS) [4,5,11,12,[43][44][45][46], TALIF [9,[47][48][49][50][51][52], appearance potential mass-spectrometry (APMS) [55][56][57][58][59][60][61][62][63][64], titration [10,24,33,37,47,49,53,54] and others. Systematically such investigations have mainly been carried out for oxygen atoms and, to a much lesser extent, for nitrogen and fluorine atoms.…”

Section: Introductionmentioning

confidence: 99%

Actinometry of O, N and F atoms

Lopaev

Volynets

Zyryanov

et al. 2017

J. Phys. D: Appl. Phys.

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The applicability of actinometry for measuring the absolute concentration of O, N and F atoms in discharge plasma was studied. For this purpose, concentrations of these atoms were measured downstream of an ICP plasma by means of the actinometry method and of appearance potential mass-spectrometry (APMS). Comparison of the results showed good agreement between the two methods. Since the excitation cross sections of electron states O(3p 3P) and O(3p 5P) applied in actinometry are well tested, this allows using the APMS method for absolute calibration of the theoretical excitation cross sections for N and F atoms. As a result, total excitation cross sections of the atomic levels N(3p 4Po), F(3p 2Po) and F(3p 4Do) have been obtained for the first time. Since different types of electron energy distribution function (EEDF) were observed (Maxwellian, bi-Maxwellian and Druyvesteyn) the influence of these possible EEDF types on actinometric coefficients (X = O, N, F), that link the ratio of the atom and actinometer intensities with that of their concentrations [X]/[Ar], was also analyzed. It was shown that at the same ionization rate (effective electron temperature) the excitation rate constants are highly sensitive to the shape of EEDF, whereas actinometric coefficients depend on it only slightly. Dependence of actinometric coefficients on electron temperature is positive if the emitting level of the X-atom is lower than that of the actinometer, and negative if vice versa. The energy difference between the emitting states of O and Ar atoms is maximal (~3 eV), so that is not constant for a whole range of electron temperatures typical for discharge plasmas (~2–8 eV). For nitrogen atoms varies considerably with Te only when Te < 4 eV. In the case of fluorine atoms the energy difference of emitting F and Ar states is only ~1 eV and coefficient is nearly constant in a wide region of Te > 1.5 eV.

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Section: Introductionmentioning

confidence: 99%

Actinometry of O, N and F atoms

Lopaev

Volynets

Zyryanov

et al. 2017

J. Phys. D: Appl. Phys.

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“…To explain our optical observations of the plasma, we also carried out numerical 1D simulations. The most widely known Ar line intensity, which is at 750 nm and which mostly represents a 4p-to-4s transition, 31) was selected for comparison between the observed and numerical study. The simulation was performed by an electron energy transition chemical reaction that emits a line intensity of 750 nm.…”

Section: Resultsmentioning

confidence: 99%

In situ monitoring of plasma ignition step in capacitively coupled plasma systems

Lee

Song

Hong

2020

Jpn. J. Appl. Phys.

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For pulsed plasma to be used in an atomic layer process, the plasma ignition step should be carefully controlled to avoid lagged plasma ignition. We observed the ignition trend of Ar plasma using an optical plasma monitoring sensor in conjunction with plasma simulations. Under several process conditions, we used optical sensors to observe the dynamic responses of plasma glow discharge to reach a steady state; the elapsed times for the plasma ignition were found to vary depending on the process/equipment settings of pressure and power, and chuck distance. We also observed the stepwise plasma ignition behavior due to the conventional radio-frequency matching system during the short period of the plasma ignition. In the present paper, we report the in situ monitoring of plasma ignition and the reasoning related to the plasma generation environment in a capacitively coupled plasma system to be considered for plasma-assisted cyclic processes, including pulsed plasma systems.

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“…A transmission curve has been obtained for the MS used in this work. Many transmission curves of MS can be found in the literature: for EQP MS from Hiden equipped with SEM [46][47][48] or for other MS [35,49,50]. They use the method described below, always using several gases among H2, He, Ne, N2, O2, Ar, Kr and Xe.…”

Section: Mass Dependence Of the Mass Spectrometer Transmissionmentioning

confidence: 99%

N₂–H₂ capacitively coupled radio-frequency discharges at low pressure. Part I. Experimental results: effect of the H₂ amount on electrons, positive ions and ammonia formation

Chatain

Jiménez-Redondo

Vettier

et al. 2020

Plasma Sources Sci. Technol.

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The mixing of N2 with H2 leads to very different plasmas from pure N2 and H2 plasma discharges. Numerous issues are therefore raised involving the processes leading to ammonia (NH3) formation. The aim of this work is to better characterize capacitively-coupled radiofrequency plasma discharges in N2 with few percents of H2 (up to 5%), at low pressure (0.3 to 1 mbar) and low coupled power (3 to 13 W). Both experimental measurements and numerical simulations are performed. For clarity, we separated the results in two complementary parts. The actual one (first part), presents the details on the experimental measurements, while the second focuses on the simulation, a hybrid model combining a 2D fluid module and a 0D kinetic module. Electron density is measured by a resonant cavity method. It varies from 0.4 to 5.10 9 cm-3 , corresponding to ionization degrees from 2.10-8 to 4.10-7. Ammonia density is quantified by combining IR absorption and mass spectrometry. It increases linearly with the amount of H2 (up to 3.10 13 cm-3 at 5% H2). On the contrary, it is constant with pressure, which suggests the dominance of surface processes on the formation of ammonia. Positive ions are measured by mass spectrometry. Nitrogen-bearing ions are hydrogenated by the injection of H2, N2H + being the major ion as soon as the amount of H2 is > 1%. The increase of pressure leads to an increase of secondary ions formed by ion/radicalneutral collisions (ex: N2H + , NH4 + , H3 +), while an increase of the coupled power favors ions formed by direct ionization (ex: N2 + , NH3 + , H2 +).

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Investigation of absolute atomic fluorine density in a capacitively coupled SF₆/O₂/Ar and SF₆/Ar discharge

Cited by 10 publications

References 56 publications

Actinometry of O, N and F atoms

Actinometry of O, N and F atoms

In situ monitoring of plasma ignition step in capacitively coupled plasma systems

N₂–H₂ capacitively coupled radio-frequency discharges at low pressure. Part I. Experimental results: effect of the H₂ amount on electrons, positive ions and ammonia formation

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Investigation of absolute atomic fluorine density in a capacitively coupled SF6/O2/Ar and SF6/Ar discharge

Cited by 10 publications

References 56 publications

Actinometry of O, N and F atoms

Actinometry of O, N and F atoms

In situ monitoring of plasma ignition step in capacitively coupled plasma systems

N2–H2 capacitively coupled radio-frequency discharges at low pressure. Part I. Experimental results: effect of the H2 amount on electrons, positive ions and ammonia formation

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Investigation of absolute atomic fluorine density in a capacitively coupled SF₆/O₂/Ar and SF₆/Ar discharge

N₂–H₂ capacitively coupled radio-frequency discharges at low pressure. Part I. Experimental results: effect of the H₂ amount on electrons, positive ions and ammonia formation