Optical investigations of the microstructure of hydrogenated amorphous carbon films

Paret, V.; Sadki, A.; Bounouh, Y.; Alameh, R.; Naud, C.; Zarrabian, M.; Seignac, A.; Turban, G.; Thèye, M. L.

doi:10.1016/s0022-3093(98)00146-x

Cited by 22 publications

(7 citation statements)

References 10 publications

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“…͑35͒. 67,68 Although n(0)ϳ2.7 holds reasonably well for hydrogenfree carbon, n(0) falls to much lower values in polymeric a-C:H. 3,71 Typical values for a a-C:H with HϾ30% are (0)ϳ3 -4 and n(0)ϳ1.8-2.2. This means that m* for these a-C:H films is less than 0.87.…”

Section: ͑28͒mentioning

confidence: 98%

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Density,sp3fraction, and cross-sectional structure of amorphous carbon films determined by x-ray reflectivity and electron energy-loss spectroscopy

et al. 2000

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Grazing-angle x-ray reflectivity ͑XRR͒ is described as an efficient, nondestructive, parameter-free means to measure the mass density of various types of amorphous carbon films down to the nanometer thickness range. It is shown how XRR can also detect layering if it is present in the films, in which case the reflectivity profile must be modeled to derive the density. The mass density can also be derived from the valence electron density via the plasmon energy, which is measured by electron energy-loss spectroscopy ͑EELS͒. We formally define an interband effective electron mass m*, which accounts for the finite band gap. Comparison of XRR and EELS densities allows us to fit an average m*ϭ0.87m for carbon systems, m being the free-electron mass. We show that, within the Drude-Lorentz model of the optical spectrum, m*ϭ͓1Ϫn(0) Ϫ2 ͔m, where n(0) is the refractive index at zero optical frequency. The fraction of sp 2 bonding is derived from the carbon K-edge EELS spectrum, and it is shown how a choice of ''magic'' incidence and collection angles in the scanning transmission electron microscope can give sp 2 fraction values that are independent of sample orientation or anisotropy. We thus give a general relationship between mass density and sp 3 content for carbon films.

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Section: ͑28͒mentioning

confidence: 98%

“…III E, once we know n(0) and the plasmon energy, we can directly get E G and m*. However can be directly obtained by other optical measurements, 71 and thus integral relations such as Eqs. ͑A4͒-͑A6͒ become more useful.…”

Section: ͑A6͒mentioning

confidence: 99%

Density,sp3fraction, and cross-sectional structure of amorphous carbon films determined by x-ray reflectivity and electron energy-loss spectroscopy

et al. 2000

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Section: Introductionmentioning

confidence: 99%

“…15,17,[23][24][25] In contrast with contact profilometry on graphite, for instance (spectroscopic) ellipsometry (SE) can be applied in situ on an a-C:H thin film. 15,17,24 Single wavelength ellipsometry is widely used in literature to investigate plasma etching. 15,17,24 Although this method has a high time resolution, the data analysis does not provide a unique solution for the thickness evolution without additional information about the initial thickness.…”

Section: Introductionmentioning

confidence: 99%

“…15,17,24 Single wavelength ellipsometry is widely used in literature to investigate plasma etching. 15,17,24 Although this method has a high time resolution, the data analysis does not provide a unique solution for the thickness evolution without additional information about the initial thickness. This issue can be circumvented through the use of spectroscopic ellipsometry.…”

Section: Introductionmentioning

confidence: 99%

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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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Amorphous Hydrogenated Carbon Nanofilm

Lin

Handbook of Performability Engineering

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Optical investigations of the microstructure of hydrogenated amorphous carbon films

Cited by 22 publications

References 10 publications

Density,sp3fraction, and cross-sectional structure of amorphous carbon films determined by x-ray reflectivity and electron energy-loss spectroscopy

Density,sp3fraction, and cross-sectional structure of amorphous carbon films determined by x-ray reflectivity and electron energy-loss spectroscopy

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

Amorphous Hydrogenated Carbon Nanofilm

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