Determination of oscillator strength of C–F vibrations in fluorinated amorphous-carbon films by infrared spectroscopy

Wang, X.; Harris, H. R.; Temkin, H.; Gangopadhyay, Shubhra; Strathman, M. D.; West, M.

doi:10.1063/1.1371970

Cited by 12 publications

(9 citation statements)

References 6 publications

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“…This analysis also assumes that a single monolayer exists on the surface with no physisorption. The surface hydrocarbon coverage can be determined from the reacted −SiOH groups using the expression ,− where υ̃ (cm –1 ) is the vibrational frequency of the isolated −SiOH groups, | A ′( ṽ )| (cm –1 ) is the change in the integrated absorbance of the isolated −SiOH feature because of reaction with C 2 H 5 COCl, σ SiOH is the corresponding infrared absorption cross section (cm 2 ), and N R (=25) is the number of internal reflections on the top face of the ZnSe IRC.…”

Section: Resultsmentioning

confidence: 99%

Gas Phase Organic Functionalization of SiO₂ with Propanoyl Chloride

et al. 2018

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The reaction mechanism of propanoyl chloride (C 2 H 5 COCl) with −SiOH-terminated SiO 2 films was studied using in situ surface infrared spectroscopy. We show that this surface functionalization reaction is temperature dependent. At 230 °C, C 2 H 5 COCl reacts with isolated surface −SiOH groups to form the expected ester linkage. Surprisingly, as the temperature is lowered to 70 °C, the ketone groups are transformed into the enol tautomer, but if the temperature is increased back to the starting exposure temperature of 230 °C, the ketone tautomer is not recovered, indicating that the enol form is thermally stable over a wide range of temperatures. Further, the enol form is directly formed after exposure of a SiO 2 surface to C 2 H 5 COCl at 70 °C. We speculate that the enol form, which is energetically unfavorable, is stabilized because of hydrogen bonding with adjacent enol groups or through hydrogen bonding with unreacted surface −SiOH groups. The surface coverage of hydrocarbon molecules is calculated as ∼6 × 10 12 cm −2 , assuming each reacted −SiOH group contributes to one hydrocarbon linkage on the surface. At a substrate temperature of 70 °C, the enol form is unreactive with H 2 O, and H 2 O molecules simply physisorb on the surface. At higher temperatures, H 2 O converts the ketone to the enol tautomer and reacts with Si−O−Si bridges, forming more −SiOH reactive sites. The overall hydrocarbon coverage on the surface can then be further increased through cycling H 2 O and C 2 H 5 COCl doses.

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Section: Resultsmentioning

confidence: 99%

Gas Phase Organic Functionalization of SiO₂ with Propanoyl Chloride

et al. 2018

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“…This index mismatch at the film/substrate interface leads to broad, shallow interference fringes in the FTIR transmission spectra [23]. The broad peak at 2000 cm À1 in Fig.…”

Section: Resultsmentioning

confidence: 98%

Ferrihydrite gels derived in the Fe(NO3)3·9H2O–C2H5OH–CH3CHCH2O ternary system

Talantsev

Pantoya

Camagong

et al. 2005

Journal of Non-Crystalline Solids

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“…Regardless of the reaction site, we assume that a single monolayer exists on the SiO 2 and SiN x surfaces. The CAZ surface coverage was calculated using the following expression: ,− where | A ′ (ν̃)| is the change in the integrated absorbance of either the isolated or vicinal −SiOH feature because of the reaction with CAZ (see Figure S1), N R (= 25) is the number of internal reflections on the top face of the ZnSe IRC, and σ is the corresponding infrared absorbance cross section (cm 2 /mol). For this analysis, we assume that the infrared absorbance cross-section is constant over the wavenumber range of the spectral feature.…”

Section: Resultsmentioning

confidence: 99%

“…The −C(CH 3 ) 3 deformation vibrational mode is observed at ∼1367 cm –1 (see Figure a and Figure S5). Because one −C(CH 3 ) 3 group is added to the SiN x surface per grafted TMH molecule, we can calculate the number density of grafted molecules on the SiN x surface as ,− where | A ′ (ν̃)| t‑butyl is the integrated absorbance (cm –1 ) of the -C(CH 3 ) 3 feature at ∼1367 cm –1 (see Figure S5), and σ t‑butyl is the infrared absorbance cross-section of this −C(CH 3 ) 3 deformation vibrational mode (cm 2 /mol).…”

Section: Resultsmentioning

confidence: 99%

Selective Gas-Phase Functionalization of SiO₂ and SiN_x Surfaces with Hydrocarbons

Gasvoda

Zhang

et al. 2021

Langmuir

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Selective functionalization of dielectric surfaces is required for area-selective atomic layer deposition and etching. We have identified precursors for the selective gas-phase functionalization of plasma-deposited SiO2 and SiN x surfaces with hydrocarbons. The corresponding reaction mechanism of the precursor molecules with the two surfaces was studied using in situ surface infrared spectroscopy. We show that at a substrate temperature of 70 °C, cyclic azasilanes preferentially react with an −OH-terminated SiO2 surface over a −NH x -terminated SiN x surface with an attachment selectivity of ∼5.4, which is limited by the partial oxidation of the SiN x surface. The cyclic azasilane undergoes a ring-opening reaction where the Si–N bond cleaves upon the reaction with surface −OH groups forming a Si–O–Si linkage. After ring opening, the backbone of the grafted hydrocarbon is terminated with a secondary amine, −NHCH3, which can react with water to form an −OH-terminated surface and release CH3NH2 as the product. The surface coverage of the grafted cyclic azasilane is calculated as ∼3.3 × 1014 cm–2, assuming that each reacted −OH group contributes to one hydrocarbon linkage. For selective attachment to SiN x over SiO2 surfaces, we determined the reaction selectivity of aldehydes. We demonstrate that aldehydes selectively attach to SiN x over SiO2 surfaces, and for the specific branched aliphatic aldehyde used in this work, almost no reaction was detected with the SiO2 surface. A fraction of the aldehyde molecules reacts with surface −NH2 groups to form an imine (Si–NC) surface linker with H2O released as the byproduct. The other fraction of the aldehydes also reacts with surface −NH2 groups but do not undergo the water-elimination step and remains attached to the surface as an aminoalcohol (Si–NH–COH−). The surface coverage of the grafted aldehyde is calculated as ∼9.8 × 1014 cm–2 using a known infrared absorbance cross-section for the −C(CH3)3 groups.

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Determination of oscillator strength of C–F vibrations in fluorinated amorphous-carbon films by infrared spectroscopy

Cited by 12 publications

References 6 publications

Gas Phase Organic Functionalization of SiO₂ with Propanoyl Chloride

Gas Phase Organic Functionalization of SiO₂ with Propanoyl Chloride

Ferrihydrite gels derived in the Fe(NO3)3·9H2O–C2H5OH–CH3CHCH2O ternary system

Selective Gas-Phase Functionalization of SiO₂ and SiN_x Surfaces with Hydrocarbons

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Determination of oscillator strength of C–F vibrations in fluorinated amorphous-carbon films by infrared spectroscopy

Cited by 12 publications

References 6 publications

Gas Phase Organic Functionalization of SiO2 with Propanoyl Chloride

Gas Phase Organic Functionalization of SiO2 with Propanoyl Chloride

Ferrihydrite gels derived in the Fe(NO3)3·9H2O–C2H5OH–CH3CHCH2O ternary system

Selective Gas-Phase Functionalization of SiO2 and SiNx Surfaces with Hydrocarbons

Contact Info

Product

Resources

About

Gas Phase Organic Functionalization of SiO₂ with Propanoyl Chloride

Gas Phase Organic Functionalization of SiO₂ with Propanoyl Chloride

Selective Gas-Phase Functionalization of SiO₂ and SiN_x Surfaces with Hydrocarbons