Stages in the interaction of deuterium atoms with amorphous hydrogenated carbon films: Isotope exchange, soft-layer formation, and steady-state erosion

Oehrlein, G. S.; Schwarz-Selinger, T.; Schmid, K.; Schlüter, Michael; Jacob, W.

doi:10.1063/1.3474988

Cited by 9 publications

(12 citation statements)

References 43 publications

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“…Therefore we attribute the first 90 min (D fluence 4.6×10 18 at.cm -2 ) to layer transformation into a soft layer which is accompanied by a small amount of erosion and, when the soft layer is formed, the steady state erosion starts. The D areal density of (5.5±1)×10 15 at.cm -2 during the steady state erosion phase has the same value as observed by Oehrlein et al 28 , which is attributed to the initial uptake by isotope exchange. Since the D areal density is more or less constant during the erosion, the D atoms act only on the top of the surface constantly transforming the a-C:H layer and maintaining the top, highly deuterated soft layer.…”

Section: Chemical Erosion Of the A-c:h Layersupporting

confidence: 72%

“…A similar study of the erosion of hard a-C:H layers by a D atom beam has been performed recently by Oehrlein et al 28 at similar atom fluxes but lower substrate temperature (330 K). Analysis was done in their case by in situ ellipsometry and ex situ by NRA and, comparing their results to ours, a similar value was obtained for the uptake of D. They have attributed the initial increase of the D areal density to isotopic exchange (up to 5×10 15 at.cm -2 ) with further D uptake of 2.5×10 15 at.cm -2 attributed to the conversion of the hard a-C:H film into a soft layer.…”

Section: Chemical Erosion Of the A-c:h Layermentioning

confidence: 84%

“…Oehrlein et al 28 could not separate unambiguously the transformation of the top layer and the onset of erosion. However, we can directly see the erosion by following the C signal and the transformation by looking at the H and D signal separately.…”

Section: Chemical Erosion Of the A-c:h Layermentioning

confidence: 99%

“…From the previous erosion experiments and available data 8,26,28 one would expect very little or no erosion of the sample. Contrary to this expectation we observed, ex situ by ellipsometry, an increase of the layer thickness for exposure at room temperature (RT) and, in some previous experiments, at a few 10 K above RT.…”

Section: Carbon Layer Depositionmentioning

confidence: 99%

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In situ study of erosion and deposition of amorphous hydrogenated carbon films by exposure to a hydrogen atom beam

Markelj

Pelicon

Čadeź

et al. 2012

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

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Here we report on the first dual-beam experiment employing a hydrogen atom beam for sample exposure and an ion beam for analysis, enabling in situ and real time studies of hydrogen atom interaction with materials. The erosion of an amorphous hydrogenated carbon (a-C:H) layer by deuterium atoms at 580 K sample temperature was studied and the uptake of deuterium during the erosion process was measured in real time. The deuterium areal density increased at the beginning to 7.3×10 15 at.cm -2 , but then stabilized at a constant value of 5.5×10 15 at.cm -2 . Formation of a polymerlike deposit on an a-C:H layer held at room temperature and subjected to the deuterium atom beam was observed and also studied in-situ. For both erosion and deposition studies an a-13 C:H layer on top of a Si substrate was used as a sample, making the experiments isotopically fully specified and thereby differentiating the deposited from the original layer and the interacting D atoms from H atoms present in the layer and in the residual vacuum. From the deposition study it was shown that carbon in the deposited layer originates from carbon-carrying species in the background vacuum that interact with hydrogen atoms. The areal density of the carbon at the surface was determined from the energy shift of the Si edge in the RBS spectrum.

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Section: Chemical Erosion Of the A-c:h Layersupporting

confidence: 72%

Section: Chemical Erosion Of the A-c:h Layermentioning

confidence: 84%

Section: Chemical Erosion Of the A-c:h Layermentioning

confidence: 99%

Section: Carbon Layer Depositionmentioning

confidence: 99%

See 2 more Smart Citations

In situ study of erosion and deposition of amorphous hydrogenated carbon films by exposure to a hydrogen atom beam

Markelj

Pelicon

Čadeź

et al. 2012

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

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“…27,30 However, these changes were reported for very high ion energies (90 À 800 eV), [27][28][29] whereas the ion energy in an expanding thermal plasma at floating potential is less than a few eV's (see also Sec. IV A).…”

Section: Hydrogenated Amorphous Carbonmentioning

confidence: 98%

Synergistic etch rates during low-energetic plasma etching of hydrogenated amorphous carbon

Hansen

Weber

Colsters

et al. 2012

Journal of Applied Physics

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The etch mechanisms of hydrogenated amorphous carbon thin films in low-energetic (<2 eV) high flux plasmas are investigated with spectroscopic ellipsometry. The results indicate a synergistic effect for the etch rate between argon ions and atomic hydrogen, even at these extremely low kinetic energies. Ion-assisted chemical sputtering is the primary etch mechanism in both Ar/H2 and pure H2 plasmas, although a contribution of swift chemical sputtering to the total etch rate is not excluded. Furthermore, ions determine to a large extent the surface morphology during plasma etching. A high influx of ions enhances the etch rate and limits the surface roughness, whereas a low ion flux promotes graphitization and leads to a large surface roughness (up to 60 nm).

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Plasma Deactivation of Endotoxic Biomolecules: Vacuum Ultraviolet Photon and Radical Beam Effects on Lipid A

Chung

Ning

Chu

et al. 2012

Plasma Processes & Polymers

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It is widely accepted that plasma‐generated energetic and reactive species are responsible for plasma‐induced sterilization; however, how these species act alone or synergistically to deactivate endotoxic biomolecules is not completely understood. Using a vacuum beam system, we study the effects of vacuum ultraviolet (VUV) radiation, oxygen and deuterium radicals on lipid A, the immune‐stimulating region of lipopolysaccharide. VUV‐induced photolysis causes bulk modification of exposed lipid A film up to the penetration depth of VUV photons, ≈200 nm. Although radical‐induced etch yield of lipid A is lower than VUV‐induced photolysis, secondary ion mass spectrometry and human whole blood‐based assay suggest that radicals render a higher degree of modification at the film surface. This study contributes to the fundamental understanding of plasma effects on biomolecules for a better deactivation scheme and applications. magnified image

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Stages in the interaction of deuterium atoms with amorphous hydrogenated carbon films: Isotope exchange, soft-layer formation, and steady-state erosion

Abstract: We report studies of the interactions of quantified deuterium (hydrogen) atom beams with hard amorphous hydrogenated carbon films at a substrate temperature of ~330 K in an ultrahighvacuum (

Cited by 9 publications

References 43 publications

In situ study of erosion and deposition of amorphous hydrogenated carbon films by exposure to a hydrogen atom beam

In situ study of erosion and deposition of amorphous hydrogenated carbon films by exposure to a hydrogen atom beam

Synergistic etch rates during low-energetic plasma etching of hydrogenated amorphous carbon

Plasma Deactivation of Endotoxic Biomolecules: Vacuum Ultraviolet Photon and Radical Beam Effects on Lipid A

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