Absolute density distribution of H atoms in a large-scale microwave plasma reactor

Duan, Xingyue; Lange, H.; Meyer‐Plath, Asmus

doi:10.1088/0963-0252/12/4/307

Cited by 10 publications

(10 citation statements)

References 21 publications

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“…Another two‐photon LIF technique following excitation at 205.1 nm can be used to detect high‐density H atoms at more than 10 13 cm −3 21, 30, 50, 52, 54, 63–66, 70, 76, 82, 94, 103–119. In this case, H(1s 2 S) is excited to H(3s 2 S) and H(3d 2 D J ) states and Balmer‐α emission at 656.3 nm is monitored.…”

Section: Experimental Techniques For Detecting H Atoms In the Gas mentioning

confidence: 99%

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Production and Detection of H Atoms and Vibrationally Excited H₂ Molecules in CVD Processes

Umemoto¹

2010

Chemical Vapor Deposition

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Radical species, including atomic hydrogen, play an important role in the CVD process to prepare high-quality thin solid films. Detailed information on the absolute densities of these radicals under various conditions is needed in order to understand the chemical kinetics involved and to control the deposition processes. This article reviews the production mechanisms and the gasphase diagnostic techniques for H atoms in catalytic CVD (also called hot-wire CVD) and plasma-enhanced (PE)CVD processes. Experimentally determined absolute H-atom densities in typical CVD processes are compiled in a table. Under suitable conditions, the steady-state H-atom density can be increased up to 10 17 cm À3. Procedures for producing and detecting vibrationally excited H 2 molecules, which can be another active species in CVD processes, are also discussed.

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Section: Experimental Techniques For Detecting H Atoms In the Gas mentioning

confidence: 99%

“…Calibration techniques have been developed, therefore, in order to scale the relative values to absolute ones. Besides VUV absorption, titration is one of the most widely used techniques 66, 74, 77, 98, 103, 105, 106, 113, 117, 118. A discharge flow system is usually used in this technique.…”

Section: Experimental Techniques For Detecting H Atoms In the Gas mentioning

confidence: 99%

Production and Detection of H Atoms and Vibrationally Excited H₂ Molecules in CVD Processes

Umemoto¹

2010

Chemical Vapor Deposition

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“…[3][4][5][6] In the literature, it is often speculated that the hydrogen to Si growth precursor flux ratio should exceed a critical value for the nucleation of crystalline phase material to occur. Although the atomic hydrogen flux during deposition can in principle be determined by advanced techniques such as two-photon laser induced fluorescence or mass spectrometry, 7,8 the technologically relevant data available concerning the abundance of atomic hydrogen during c-Si: H deposition remain largely based on correlations with indirect optical emission spectroscopy measurements and modeling work. 6,[9][10][11][12][13] Preferential insertion of atomic hydrogen in strained Si-Si bonds and subsequent silicon etching lead to a higher etch rate of amorphous silicon ͑a-Si: H͒ relative to crystalline Si.…”

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confidence: 99%

The atomic hydrogen flux to silicon growth flux ratio during microcrystalline silicon solar cell deposition

Dingemans

Donker

Hrunski

et al. 2008

Applied Physics Letters

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The H flux to Si growth flux ratio is experimentally determined under state-of-the-art silicon thin-film deposition conditions by employing the recently introduced etch product detection technique. Under the technologically relevant high-pressure depletion conditions and for different process parameter settings such as pressure, SiH4 concentration, rf power, and excitation frequency, it was demonstrated that the microcrystalline to amorphous silicon phase transition is uniquely and reactor independently determined by the flux ratio of H and Si growth species.

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“…Since then, a plethora of experimental and numerical studies has emerged. These studies validated the excellent capability of TALIF to determine atomic densities in flames and plasmas [28,36,[39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54]. The concept of this method is depicted in Figure 2.…”

Section: Talif Principles Involved Theory and Experimental Requirementsmentioning

confidence: 56%

Progresses on the Use of Two-Photon Absorption Laser Induced Fluorescence (TALIF) Diagnostics for Measuring Absolute Atomic Densities in Plasmas and Flames

Lombardi

Aubert

Duluard

et al. 2021

Plasma

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Recent developments in plasma science and technology have opened new areas of research both for fundamental purposes (e.g., description of key physical phenomena involved in laboratory plasmas) and novel applications (material synthesis, microelectronics, thin film deposition, biomedicine, environment, flow control, to name a few). With the increasing availability of advanced optical diagnostics (fast framing imaging, gas flow visualization, emission/absorption spectroscopy, etc.), a better understanding of the physicochemical processes taking place in different electrical discharges has been achieved. In this direction, the implementation of fast (ns) and ultrafast (ps and fs) lasers has been essential for the precise determination of the electron density and temperature, the axial and radial gradients of electric fields, the gas temperature, and the absolute density of ground-state reactive atoms and molecules in non-equilibrium plasmas. For those species, the use of laser-based spectroscopy has led to their in situ quantification with high temporal and spatial resolution, with excellent sensitivity. The present review is dedicated to the advances of twophoton absorption laser induced fluorescence (TALIF) techniques for the measurement of reactive species densities (particularly atoms such as N, H and O) in a wide range of pressures in plasmas and flames. The requirements for the appropriate implementation of TALIF techniques as well as their fundamental principles are presented based on representative published works. The limitations on the density determination imposed by different factors are also discussed. These may refer to the increasing pressure of the probed medium (leading to a significant collisional quenching of excited states), and other issues originating in the high instantaneous power density of the lasers used (such as photodissociation, amplified stimulated emission, and photoionization, resulting to the saturation of the optical transition of interest).

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Absolute density distribution of H atoms in a large-scale microwave plasma reactor

Cited by 10 publications

References 21 publications

Production and Detection of H Atoms and Vibrationally Excited H₂ Molecules in CVD Processes

Production and Detection of H Atoms and Vibrationally Excited H₂ Molecules in CVD Processes

The atomic hydrogen flux to silicon growth flux ratio during microcrystalline silicon solar cell deposition

Progresses on the Use of Two-Photon Absorption Laser Induced Fluorescence (TALIF) Diagnostics for Measuring Absolute Atomic Densities in Plasmas and Flames

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Absolute density distribution of H atoms in a large-scale microwave plasma reactor

Cited by 10 publications

References 21 publications

Production and Detection of H Atoms and Vibrationally Excited H2 Molecules in CVD Processes

Production and Detection of H Atoms and Vibrationally Excited H2 Molecules in CVD Processes

The atomic hydrogen flux to silicon growth flux ratio during microcrystalline silicon solar cell deposition

Progresses on the Use of Two-Photon Absorption Laser Induced Fluorescence (TALIF) Diagnostics for Measuring Absolute Atomic Densities in Plasmas and Flames

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Product

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Production and Detection of H Atoms and Vibrationally Excited H₂ Molecules in CVD Processes

Production and Detection of H Atoms and Vibrationally Excited H₂ Molecules in CVD Processes