INFRARED SPECTROSCOPY OF a-SiC:H FILMS

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Thin films of tetravinylsilane or its mixture with oxygen gas were prepared by plasma-enhanced chemical vapour deposition (PECVD) operating in pulsed mode. The oxygen-to-total-flow rate ratio (0 – 0.92) and effective power (2 – 150 W) were the only variable deposition parameters. The films deposited on silicon wafer were analyzed by infrared spectroscopy to evaluate the chemical structure of the deposited material. Infrared transmission measurements were made using a VERTEX 80 vacuum Fourier transform infrared (FTIR) spectrometer (Bruker Optics, USA) in the wavenumber range of 400 – 4000 cm-1. For background noise reduction 256 scans was selected in the experimental set up and the spectral resolution was 4 cm-1. The background correction was carried out before each measurement to avoid any contribution from the residual atmosphere. To remove the spectral features of the silicon wafer and interference effects, an absorption subtraction technique was used. The assignment of IR absorption bands was carried. According to this assignment, the intensity and the area of the absorption band corresponding to CO2 vibrations increased with enhancement in oxygen flow rate and effective power up to 3 sccm and 30 W, respectively and then decreases with further increase in oxygen flow rate and effective power. Infrared spectra indicated the incorporation of CO2 gas into the thin films, which could be due to porous strucrure of as-preapared thin films. To confirm this assumption, GISAXS analysis (grazing-incidence small-angle scattering) was performed.

thin films; infrared spectroscopy

ABOUALI GALEDARI, N.; BRÁNECKÝ, M.; ČECH, V.

3. 10. 2019

III. Setkání uživatelů FTIR a Ramanových spektrometrů BRUKER, Brno

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