Resumo

VAZQUEZ-VALERDI, D. E. et al. Propiedades ópticas, de composición y morfológicas de películas delgadas de SiO_x depositadas por HFCVD. Superf. vacío [online]. 2011, vol.24, n.2, pp.54-60. ISSN 1665-3521.

In this work, the morphological, compositional and optical properties of SiO_x films are studied using Atomic Force Microscopy (AFM), Fourier Transformed Infrared spectroscopy (FTIR), Photoluminescence (PL), UV-Vis Transmittance and null Ellipsometry. These films were obtained by the Hot Filament Chemical Vapor Deposition (HFCVD) technique in a range of temperatures from 750 to 1005 °C. The PL spectra of the SiO_x films deposited on quartz to 813, 873 and 950 °C show a shift within 650 nm and 712 nm as the substrate temperature (T_s) is increased. From these results it is proposed that the PL is originated from quantum confinement effects in silicon nanocrystals (Si-nc) embedded in the silicon oxide matrix, since the Si-nc decreased in size as T_s is reduced and produce a blueshift in the PL spectra. Transmittance spectra were obtained; with the analyses of these spectra, the energy gap (E_g) was obtained. Quantum confinement effective mass model was used to obtain the average size of the Si-nc, which is found between 3.51 and 2.22 nm. Also, different defects of the films deposited on quartz and silicon substrate have relation with the behaviour of the observed PL spectra.

Palavras-chave : SiO_x; AFM; FTIR; PL; Si-nc.

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