Charge carrier dynamics in a pulsed inductive RF discharge in oxygen

Katsch, H. M.; Manthey, C.; Döbele, H. F.

doi:10.1088/0963-0252/12/3/324

Cited by 21 publications

(36 citation statements)

References 49 publications

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“…Nevertheless, a similar increase of n O − was not measured in the afterglow of oxygen discharges with inductive rf coupling [5] and modeling of high density low pressure oxygen discharges [8] has also not confirmed an increase of the negative ion density in the afterglow.…”

Section: Introductionmentioning

confidence: 87%

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Negative Ions in Helicon Oxygen Discharges

Sydorenko

Grulke

Matyash

et al. 2009

Contrib. Plasma Phys.

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The negative oxygen ion density is studied experimentally in the high-density helicon device VINETA by laserinduced photodetachment. The measurements indicate a negative ion density being higher than the electron density in contrast to previous experiments in helicon oxygen discharges. The dependency of the relative negative ion density on the oxygen gas pressure and rf-power is in good qualitative agreement with observations in low temperature RF inductive and capacitive discharges, but differ quantitatively by one order of magnitude. To understand the basic physics in the helicon discharges, the measurements are compared to a zero dimensional reaction rate model of the electronegative oxygen discharge. The particle densities are calculated via rate equations estimated from collisional cross sections assuming Maxwellian electron energy distribution functions. The model shows that the electron temperature is the most sensitive parameter governing the formation of negative oxygen ions. Additionally, the differences to previous experimental measurements in rf discharges can be explained by different electron temperature and plasma losses to the walls.

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Section: Introductionmentioning

confidence: 87%

“…Recently, a lot of measurements and theoretical modeling have been done for capacitive [1][2][3][4] and inductive oxygen discharges [5], which have shown that the density of atomic oxygen and metastable oxygen molecules O 2 (a 1 Δ g ) have a strong influence on the negative ion density. Both of these discharge modes are well investigated.…”

Section: Introductionmentioning

confidence: 99%

Negative Ions in Helicon Oxygen Discharges

Sydorenko

Grulke

Matyash

et al. 2009

Contrib. Plasma Phys.

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“…This confinement can last even to the late after-glow. [38] By means of photo-detachment technology and a Langmuir probe, Wagner et al found that the density of the negative ions forms a peak at about 150 µs after the power is turned off. This is because O − mainly generated from the reaction…”

Section: After-glow Periodmentioning

confidence: 99%

“…, and the cross section of this reaction increases with decreasing electron temperatures. [38] Besides, the formation of O − via the electron dissociative attachments with the ground state of O 2 (with a threshold of 4.7 eV) and the O 2 (a 1 ∆ g ) (with a threshold of 3.72 eV) can be excluded in the after-glow. [22] As a consequence, the electrons at the chamber center will be consumed via the dissociative attachment e + O M 2 → O − + O, producing O − at the same time.…”

Section: After-glow Periodmentioning

confidence: 99%

Time-resolved radial uniformity of pulse-modulated inductively coupled O₂/Ar plasmas*

Liu¹,

Xue²,

Gao³

et al. 2021

Chinese Phys. B

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Time-resolved radial uniformity of pulse-modulated inductively coupled O2/Ar plasma has been investigated by means of a Langmuir probe as well as an optical probe in this paper. The radial uniformity of plasma has been discussed through analyzing the nonuniformity factor β (calculated by the measured n e, lower β means higher plasma radial uniformity). The results show that during the active-glow period, the radial distribution of n e exhibits an almost flat profile at the beginning phase, but it converts into a parabola-like profile during the steady state. The consequent evolution for β is that when the power is turned on, it declines to a minimum at first, and then it increases to a maximum, after that, it decays until it keeps constant. This phenomenon can be explained by the fact that the ionization gradually becomes stronger at the plasma center and meanwhile the rebuilt electric field (plasma potential and ambipolar potential) will confine the electrons at the plasma center as well. Besides, the mean electron energy (〈 ε 〉on) at the pulse beginning decreases with the increasing duty cycle. This will postpone the plasma ignition after the power is turned on. This phenomenon has been verified by the emission intensity of Ar (; = 750.4 nm). During the after-glow period, it is interesting to find that the electrons have a large depletion rate at the plasma center. Consequently, n e forms a hollow distribution in the radial direction at the late stage of after-glow. Therefore, β exhibits a maximum at the same time. This can be attributed to the formation of negative oxygen ion (O−) at the plasma center when the power has been turned off.

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“…The existence of two distinctive operational modes makes the ICPs very attractive field of study because of the fascinating features of the discharge and the underlying complicated physics. There are many theoretical and experimental studies wherein different plasma parameters are investigated in H-mode of the oxygen ICPs for various operational discharge parameters [16][17][18][19]. However, very little work has been done in E-mode or both modes simultaneously in the oxygen ICPs [20,21].…”

Section: Introductionmentioning

confidence: 99%

Mode Transition in Magnetic-Pole-Enhanced Inductively Coupled Oxygen Plasma

Khan¹,

Khattaka²

2019

IJASTR

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Electronegative oxygen gas is used in many technological and industrial applications. In this paper, the vital parameters are investigated in two distinctive operational modes (E-& H-modes) of the "magnetic-pole-enhanced inductively coupled plasma" (MaPE-ICP) driven in oxygen with a small amount of actinometer (4% argon) for various applied powers (40-300 W) and gas pressures (15-60 mTorr). The key plasma parameters including electron density and electron temperature are determined by a Langmuir probe, whereas the dissociation fraction is estimated by actinometry which is a renowned optical emission spectroscopy technique. The determination of plasma parameters as a function of gas pressure and applied power is required to understand the discharge kinetics and upgrade the processing applications. The results obtained in the MaPE-ICP are compared with the traditional ICPs, and some interesting similarities and differences between the two schemes are reported.

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Charge carrier dynamics in a pulsed inductive RF discharge in oxygen

Cited by 21 publications

References 49 publications

Negative Ions in Helicon Oxygen Discharges

Negative Ions in Helicon Oxygen Discharges

Time-resolved radial uniformity of pulse-modulated inductively coupled O₂/Ar plasmas*

Mode Transition in Magnetic-Pole-Enhanced Inductively Coupled Oxygen Plasma

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Charge carrier dynamics in a pulsed inductive RF discharge in oxygen

Cited by 21 publications

References 49 publications

Negative Ions in Helicon Oxygen Discharges

Negative Ions in Helicon Oxygen Discharges

Time-resolved radial uniformity of pulse-modulated inductively coupled O2/Ar plasmas*

Mode Transition in Magnetic-Pole-Enhanced Inductively Coupled Oxygen Plasma

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Product

Resources

About

Time-resolved radial uniformity of pulse-modulated inductively coupled O₂/Ar plasmas*