Use of optical emission spectroscopy for determining the number concentration of chlorine atoms in a chlorine-oxygen plasma

Skorodumov, A. E.; Sitanov, D. V.; Svettsov, V. I.

doi:10.1007/bf02762688

Cited by 5 publications

(4 citation statements)

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“…Figure 4 a shows that signal peaks of OH, CH, C 2 , and series H can be found in both spectrums, but the signal peak of chlorine element at 452.6 nm can merely be detected in the chloroform assisted system, which is different from the non‐chloroform assisted system and is the main reason for improvement for growth rate. [ 38 , 39 ] In addition, in the chloroform system, the ratio of relative concentration of hydroxyl to hydrogen radical is 0.32, and the ratio of carbon species to hydrogen radical is 0.69, which is much higher than 0.12 and 0.53 in the non‐chloroform system, respectively. The more hydroxyl in the chloroform assisted system contributes to rapid growth of VG (Figure 4b ).…”

Section: Resultsmentioning

confidence: 99%

Chloroform‐Assisted Rapid Growth of Vertical Graphene Array and Its Application in Thermal Interface Materials

Cheng

Shen

et al. 2022

Advanced Science

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With the continuous progress in electronic devices, thermal interface materials (TIMs) are urgently needed for the fabrication of integrated circuits with high reliability and performance. Graphene as a wonderful additive is often added into polymer to build composite TIMs. However, owing to the lack of a specific design of the graphene skeleton, thermal conductivity of graphene-based composite TIMs is not significantly improved. Here a chloroform-assisted method for rapid growth of vertical graphene (VG) arrays in electric field-assisted plasma enhanced chemical vapor deposition (PECVD) system is reported. Under the optimum intensity and direction of electric field and by introducing the highly electronegative chlorine into the reactor, the record growth rate of 11.5 μm h −1 is achieved and VG with a height of 100 μm is successfully synthesized. The theoretical study for the first time reveals that the introduction of chlorine accelerates the decomposition of methanol and thus promotes the VG growth in PECVD. Finally, as an excellent filler framework in polymer matrix, VG arrays are used to construct a free-standing composite TIM, which yields a high vertical thermal conductivity of 34.2 W m −1 K −1 at the graphene loading of 8.6 wt% and shows excellent cooling effect in interfacial thermal dissipation of light emitting diode.

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Section: Resultsmentioning

confidence: 99%

Chloroform‐Assisted Rapid Growth of Vertical Graphene Array and Its Application in Thermal Interface Materials

Cheng

Shen

et al. 2022

Advanced Science

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“…We are aware of only a handful of experimental characterizations of Cl 2 /O 2 plasmas that demonstrate the behavior of the various plasma parameters with oxygen dilution [14,15,[17][18][19]. Guha and Donnelly [14] measured the electron temperature, the electron, positive ion and atomic chlorine densities as a function of oxygen dilution for their study of the wall recombination coefficient γ rec in a Cl 2 /O 2 discharge.…”

Section: Comparison With Measurementsmentioning

confidence: 99%

“…Efremov et al [15][16][17] investigated the influence of the Cl 2 /O 2 mixing ratio on the various plasma parameters both theoretically and experimentally in an inductively coupled discharge. Skorodumov et al [18] measured the atomic chlorine density by optical emission spectroscopy in a Cl 2 /O 2 dc discharge and Hsu et al [19] compared results of a fluid model with measurements in mixtures of O 2 , Cl 2 and Ar in an inductively coupled discharge.…”

Section: Introductionmentioning

confidence: 99%

The low pressure Cl₂/O₂discharge and the role of ClO

Thorsteinsson¹,

Guðmundsson²

2010

Plasma Sources Sci. Technol.

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A global (volume averaged) model is applied to a low pressure (1-100 mTorr) high density chlorine discharge that is diluted with oxygen. The influence of oxygen dilution on the particle densities and the electron temperature is explored. The electronegativity is found to increase strongly with increased pressure in a chlorine-rich mixture, whereas it is nearly pressure independent in an oxygen-rich mixture. The chlorine dissociation fraction increases with increased oxygen dilution, although the increase is neither pronounced nor sharp at low oxygen content. We explore the role of the ClO molecule in the discharge and confirm that the ClO molecule is mainly created through recombination of Cl and O atoms at the chamber wall, which in turn significantly increases the loss of Cl atoms in oxygen-rich mixtures. The most important loss process for ClO is electron impact dissociation in the plasma bulk. The molecular ion ClO + is almost entirely created by charge transfer for oxygen dilution below 67%, while electron impact ionization becomes the dominant creation process for ClO + at higher dilution.

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“…The probe operating in Voltage Mode can get exposed by the electromagnetic noise in pulsed DC plasmas causing notable error in the measurements [10]. plasma dynamic thrusters [11,13], discharge plasmas [14], plasma guns [14,15] A triple Langmuir probe consists of three exposed tips; two of them are biased with a DC voltage source and third one acts as an independent floating probe [10,12]. Let's consider three tips namely P 1 , P 2 , and P 3 inserted into the plasma discharge.…”

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confidence: 99%

Time function triple Langmuir probe measurements in low frequency pulsed DC discharge plasma

et al. 2015

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286 1 Different plasma parameters including the electron temperature (T e ), electron number density (n e ), float ing potential, electron energy distribution function (EEDF), etc. can reliably be investigated with Lang muir probes [1,2]. From the time when Langmuir probe was invented, several physicists have derived theories and published the work to solve the difficulties in explaining the probes data for their applications as power full plasma diagnostics [1][2][3][4]. The triple Lang muir probe has several benefits over standard single and double Langmuir probes. It allows immediate measurements of plasma parameters in pulsed DC plasmas without requirement of the sweep voltage [5,6]. The pulsed DC discharges have many advantages over simple DC discharges. In DC discharge, ions in the plasma gain more and more energy with rise in input power. As a result, temperature of the cathode increases by causing transition from abnormal glow discharge to an arc [7]. This transition to an arc region can be suppressed effectively by using pulsed DC dis charge instead of a simple DC discharge [2,8]. In plasma processing, the substrate temperature can be Abstract-This study investigated the temporal profiles of electron temperature and number density in rec tified DC air discharge generated with a 50 Hz step up transformer. An in house built triple Langmuir probe and circuitry were used to diagnose the plasma parameters as a function of input voltage and filling gas pres sure. A tungsten metal wire capable of withstanding the high temperatures was used as probe tip material. The temporal profiles revealed an increase in electron temperature with input voltage in the range of 380 to 450 V, whereas, an inverse relation between number density and input voltage was evident in the given work. The observed trend in the plasma parameters was absolutely reversed in case of the filling gas pressure. The elec tron temperature linearly decreased with an increase in pressure from 1 to 4 mbar, whereas a linear increase in number density with pressure was seen in the temporal profiles. Finally, it was concluded that the results for the tested plasma parameters were consistent and the in house built probe functioned well in DC dis charge for the used range of voltage and filling pressure.

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Use of optical emission spectroscopy for determining the number concentration of chlorine atoms in a chlorine-oxygen plasma

Cited by 5 publications

References 1 publication

Chloroform‐Assisted Rapid Growth of Vertical Graphene Array and Its Application in Thermal Interface Materials

Chloroform‐Assisted Rapid Growth of Vertical Graphene Array and Its Application in Thermal Interface Materials

The low pressure Cl₂/O₂discharge and the role of ClO

Time function triple Langmuir probe measurements in low frequency pulsed DC discharge plasma

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Use of optical emission spectroscopy for determining the number concentration of chlorine atoms in a chlorine-oxygen plasma

Cited by 5 publications

References 1 publication

Chloroform‐Assisted Rapid Growth of Vertical Graphene Array and Its Application in Thermal Interface Materials

Chloroform‐Assisted Rapid Growth of Vertical Graphene Array and Its Application in Thermal Interface Materials

The low pressure Cl2/O2discharge and the role of ClO

Time function triple Langmuir probe measurements in low frequency pulsed DC discharge plasma

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The low pressure Cl₂/O₂discharge and the role of ClO