Metastables as a probe for low-temperature plasma characteristics in argon

Makabe, Toshiaki

doi:10.1088/1361-6463/ab0531

Cited by 11 publications

(11 citation statements)

References 152 publications

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“…During the experiment, the collision frequency increases gradually with the slow increase in the temperature of the gas discharge tube, usually from 1 GHz to 3 GHz [15]. Figure 1(b) shows the simulated and measured transmission curve of the sample in figure 1(a).…”

Section: Plasma Diagnosismentioning

confidence: 99%

Transmission and backscattering characteristics of electromagnetic waves in single layer combined plasma array

Deng¹,

Li²,

Shi³

et al. 2022

J. Phys. D: Appl. Phys.

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Manipulation of electromagnetic (EM) waves is essential for various microwave applications. This research studies the modulation of EM waves by using single-layer plasma arrays consisting of discharge tubes. We experimentally investigate the transmission spectra and backscattering attenuation characteristics of the plasma arrays, and numerical simulations further reveal the modulation mechanism and influences of the plasma arrays. The experimental and numerical results show that broadband tunable photonic bandgaps can be achieved in frequency ranges of 4–7.5 GHz and 7–9.5 GHz for the transmission spectrum and the backscattering spectrum, respectively. In addition, the proposed plasma array can achieve different modulation effects to satisfy the corresponding scenario requirements by adjusting the configuration and parameters such as the plasma frequency, spacing of the plasma tubes, and the discharge tube’s excitation or extinction of the plasma array. The wave manipulation of the combined plasma array creates opportunities for developing numerous applications, including large-area spatial filtering, radar stealth, and reconfigurable antennas.

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Section: Plasma Diagnosismentioning

confidence: 99%

Transmission and backscattering characteristics of electromagnetic waves in single layer combined plasma array

Deng¹,

Li²,

Shi³

et al. 2022

J. Phys. D: Appl. Phys.

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“…[8][9][10][11][12][13]22,23) This is one of a series of reviews of nonequilibrium, collisional low-temperature RF plasma research published in the past 30 (or 70) years. 27,28)…”

Section: Positioning Of Electronegative Plasmas and The Present Purposementioning

confidence: 99%

Current status and nature of high-frequency electronegative plasmas: basis for material processing in device manufacturing

Makabe

2019

Jpn. J. Appl. Phys.

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A non-equilibrium electronegative plasma serves as the reactive source for semiconductor dry processing as an advanced technology. This paper reviews the current knowledge about the fundamental processes, structures, dynamics, and functions of high-frequency electronegative plasmas investigated over the past 30 years, and discusses the hidden characteristics originating from a majority of positive and negative ions and a minority of electrons. A unique structure with a negative ion layer is emphasized in terms of the sustaining mechanism underlying capacitively coupled plasma. In a strong electronegativity, the main sustaining mechanism is caused by a cluster of ionizations placed in front of the instantaneous anode by a minority of electrons accelerated from the bulk plasma into the active double layer. A new insight is obtained for how to hold a bulk plasma. The bulk plasma is maintained by a time-averaged net ionization rate equal to the electron attachment by minority electrons under the assistance of a relatively high reduced field E(t)/Ng in order to compensate for the large loss by ion–ion recombination. The structure is quite different from that of an electropositive plasma having a low reduced field under ambipolar diffusion. It is proposed that it will be possible to estimate the high value of E(t)/Ng in bulk plasma in a strongly electronegative plasma on the basis of the static DC breakdown theory in electronegative gas.

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“…Lee et al [36] established a coupling model for the discharge power of a planar coil under a weak magnetic field, and believe that the excitation of the plasma wave is one of the reasons causing additional electronic damping. Furthermore, when the axial magnetic field is high (above 100 G), the helicon wave mode appears under high power, and the role of highenergy electrons is more prominent [11,[37][38][39]. Therefore, the strength of the external magnetic field significantly affects the electron heating mechanism, which in turn affects the ionization process.…”

Section: Introductionmentioning

confidence: 99%

E-H mode transitions and high-energy electron characteristics of helical antenna coupled plasma

Wang¹,

Lin²,

Li³

et al. 2021

J. Phys. D: Appl. Phys.

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Metastable and high-energy electron characteristics obtained from optical emission spectroscopy are used to analyze the dependence of the H mode on the magnetic field strength and discharge pressure. The results show that the H-mode characteristics gradually appears as the magnetic field strength is increased, the reason being that electrons undergo multiple acceleration-collision cycles at high magnetic field strength, thereby the metastable ionization will be increased. This improves energy utilization and making the H mode appearing. The variation in the density of metastable states and the Langmuir probe data shows that the electron energy distribution function evolves from non-Maxwellian to Maxwellian. The radial constraint of the magnetic field to the electrons and thus reduces the electron heating efficiency. Moreover, the increase in electric field strength with magnetic field leads to an increase in energy obtained by the electrons per unit distance. The competition between the two makes the number of high-energy electrons decrease rapidly first, and then increase slowly with magnetic field strength increasing. The turning point increases with the increase of discharge pressure and radio-frequency (RF) power. And the higher the pressure the lower the high-energy electron. For fields between 105.5 G and 212.7 G. In the H-mode regime, and with increasing RF power, the number of high-energy electrons will be sudden rise after experiencing a steady increase. The sudden rise RF power increase with magnetic field and decrease with discharge pressure increase. However, at high magnetic fields (>265 G) and high power (>450 W), the high-energy electron density decreases with power increasing.

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Metastables as a probe for low-temperature plasma characteristics in argon

Cited by 11 publications

References 152 publications

Transmission and backscattering characteristics of electromagnetic waves in single layer combined plasma array

Transmission and backscattering characteristics of electromagnetic waves in single layer combined plasma array

Current status and nature of high-frequency electronegative plasmas: basis for material processing in device manufacturing

E-H mode transitions and high-energy electron characteristics of helical antenna coupled plasma

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