In-Situ Surface Recombination Measurements of Oxygen Atoms on Anodized Aluminum in an Oxygen Plasma

Guha, Joydeep; Kurunczi, P.; Stafford, L.; Donnelly, Vincent M.; Pu, Yi‐Kang

doi:10.1021/jp800788a

Cited by 26 publications

(18 citation statements)

References 28 publications

(77 reference statements)

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“…In the case of AA, recombination coefficients varied from γ O = 0.06 ± 0.02 in the limit of low O flux (Γ O ≤ 1 × 10 16 cm -2 s -1 ) to γ O = 0.04 ± 0.02 0.01 at Γ O = 7.5 × 10 16 cm -2 s -1 . These values are comparable to the γ O = 0.04 ± 0.01 value found on a sputtered silica surface [33].…”

Section: Determination Of Recombination Coefficients Using the Spinnisupporting

confidence: 87%

“…These results were reported in previous publications [32,33], only the highlights are recalled here. For SS, Fig.…”

Section: Determination Of Recombination Coefficients Using the Spinnisupporting

confidence: 86%

“…A "spinning-wall" technique was recently developed for studying surface reactions on plasma reactor walls [28][29][30][31][32][33][34][35][36][37]. This method couples the established ultra-high-vacuum techniques of desorption MS and AES to the high-pressure, high-charge-density plasma environment.…”

Section: Introductionmentioning

confidence: 99%

“…A small, cylindrical substrate is rapidly rotated through skimmers such that a point of the surface is periodically exposed to the plasma and is analyzed in near real-time by surface diagnostics in separate, differentially pumped chambers. This paper reviews and compares previously published spinning-wall studies of the recombination dynamics of O and Cl atoms on plasma-conditioned AA and SS surfaces [28][29][30][31][32][33][34][35]. Cl atom recombination rate was also obtained by fitting an isothermal fluid model to measured degrees of dissociation of Cl 2 obtained in low-pressure, high-density Cl 2 plasmas sustained by traveling electromagnetic surface waves.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and modeling study of O and Cl atoms surface recombination reactions in O2 and Cl2 plasmas

Stafford

Guha

Khare

et al. 2010

Pure and Applied Chemistry

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Abstract:In low-pressure plasmas commonly used in materials processing, plasma-wall inter actions play a crucial role in the evolution of the plasma properties both over time and across large-area wafers. We have recently studied the heterogeneous recombination of O and Cl atoms on reactor walls in O 2 and Cl 2 plasmas through both experiments and modeling. The Langmuir-Hinshelwood (i.e., delayed) recombination was investigated using a "spinning-wall" technique in which a portion of the substrate surface is periodically exposed to an inductively coupled plasma and to a differentially pumped chamber where either Auger electron spectroscopy (AES) or line-of-sight mass spectrometry (MS) is used to detect surface and desorbing species. In this paper, a review of the various effects driving the O and Cl atoms recombination dynamics on anodized aluminum (AA) and stainless steel (SS) surfaces is presented. It is shown that recombination probabilities, γ, can vary following plasma exposure due to surface conditioning. In Cl 2 plasmas, γ was also found to depend on the Cl-toCl 2 number density ratio, a mechanism ascribed to a competition for adsorption sites between Cl and Cl 2 . We have also determined the recombination rates of Cl atoms in Cl 2 high-density plasmas sustained by electromagnetic surface waves by comparing the measured degrees of dissociation of Cl 2 to those predicted by an isothermal fluid model. For a reactor with large SS and quartz surfaces exposed to the plasma, γ values and their dependence on the Cl-toCl 2 number density ratio were consistent with those obtained from the rotating substrate technique. Similar values were obtained for plasmas sustained in a quartz discharge tube. It is expected that for plasmas sustained in or adjacent to a silica tube or plate, the Cl atoms recombination coefficient becomes independent of chamber wall material due to reactor seasoning, producing a silicon-oxychloride layer.

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Section: Determination Of Recombination Coefficients Using the Spinnisupporting

confidence: 87%

“…These results were reported in previous publications [32,33], only the highlights are recalled here. For SS, Fig.…”

Section: Determination Of Recombination Coefficients Using the Spinnisupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Experimental and modeling study of O and Cl atoms surface recombination reactions in O2 and Cl2 plasmas

Stafford

Guha

Khare

et al. 2010

Pure and Applied Chemistry

Self Cite

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“…35 A Langmuir-Hinshelwood (L-H) O recombination coefficient of 0.036 was derived from these values using the procedure described previously, 27,28 where desorption fluxes were extrapolated to 1/f ¼ 0. After O 2 plasma conditioning, O 2 pressure rise measurements were taken for a 1.5 mTorr, 400 W O 2 ICP.…”

Section: Methodsmentioning

confidence: 99%

Interactions of chlorine plasmas with silicon chloride-coated reactor walls during and after silicon etching

Khare

Srivastava

Donnelly

2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Mass and Auger electron spectroscopy studies of the interactions of atomic and molecular chlorine on a plasma reactor wallHigh temperature reaction of nitric oxide with Si surfaces: Formation of Si nanopillars through nitride masking and oxygen etching Modification of a high vacuum, crossed molecular beam scattering system to perform angle-resolved, gassurface scattering studies under ultrahigh vacuum conditions Rev.The interplay between chlorine inductively coupled plasmas (ICP) and reactor walls coated with silicon etching products has been studied in situ by Auger electron spectroscopy and line-of-sight mass spectrometry using the spinning wall method. A bare silicon wafer mounted on a radio frequency powered electrode (À108 V dc self-bias) was etched in a 13.56 MHz, 400 W ICP. Etching products, along with some oxygen due to erosion of the discharge tube, deposit a Si-oxychloride layer on the plasma reactor walls, including the rotating substrate surface. Without Si-substrate bias, the layer that was previously deposited on the walls with Si-substrate bias reacts with Cl-atoms in the chlorine plasma, forming products that desorb, fragment in the plasma, stick on the spinning wall and sometimes react, and then desorb and are detected by the mass spectrometer. In addition to mass-to-charge (m/e) signals at 63, 98, 133, and 168, corresponding to SiCl x (x ¼ 1 -4), many Si-oxychloride fragments with m/e ¼ 107, 177, 196, 212, 231, 247, 275, 291, 294, 307, 329, 345, 361, and 392 were also observed from what appear to be major products desorbing from the spinning wall. It is shown that the evolution of etching products is a complex "recycling" process in which these species deposit and desorb from the walls many times, and repeatedly fragment in the plasma before being detected by the mass spectrometer. SiCl 3 sticks on the walls and appears to desorb for at least milliseconds after exposure to the chlorine plasma. Notably absent are signals at m/e ¼ 70 and 72, indicating little or no Langmuir-Hinshelwood recombination of Cl on this surface, in contrast to previous studies done in the absence of Si etching.

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Deterministic and Monte Carlo methods for simulation of plasma‐surface interactions

Marinov

Teixeira

Guerra

2016

Plasma Processes & Polymers

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Two approaches to the modeling of surface kinetics in reactive plasmas are discussed. Coarse‐grained deterministic models incorporate rate balance equations for coverages of surface active sites. They are computationally effective and can be readily coupled to reactor‐scale plasma simulations. In the kinetic Monte Carlo (KMC) approach, the time evolution of a gas‐lattice system consisting of a large number of particles is described. Although being more demanding computationally, KMC algorithms are exact, allow a straightforward description of distributions of surface reactivity and help bridging the gap between simulations on atomic and macroscopic scales. In this paper, theoretical and practical aspects of deterministic and KMC modeling of plasma‐surface interactions are discussed taking O recombination on silica as a model system.

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In-Situ Surface Recombination Measurements of Oxygen Atoms on Anodized Aluminum in an Oxygen Plasma

Cited by 26 publications

References 28 publications

Experimental and modeling study of O and Cl atoms surface recombination reactions in O2 and Cl2 plasmas

Experimental and modeling study of O and Cl atoms surface recombination reactions in O2 and Cl2 plasmas

Interactions of chlorine plasmas with silicon chloride-coated reactor walls during and after silicon etching

Deterministic and Monte Carlo methods for simulation of plasma‐surface interactions

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