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Si-rich a-SiC:H thin films: Structural and optical transformations during thermal annealing

: Künle, M.; Kaltenbach, T.; Löper, P.; Hartel, A.; Janz, S.; Eibl, O.; Nickel, K.G.


Thin solid films 519 (2010), Nr.1, S.151-157
ISSN: 0040-6090
Fraunhofer ISE ()

Amorphous hydrogenated silicon-rich silicon carbide (a-Si0.8C0.2:H) thin films were prepared by plasma enhanced chemical vapour deposition and were thermally annealed in a conventional resistance heated furnace at annealing temperatures up to 1100 °C. The annealing temperatures were varied and the samples were characterised with Auger electron spectroscopy, glancing incidence X-ray diffraction, Raman spectroscopy, Fourier transformed infrared spectroscopy, transmission electron microscopy and photoluminescence (PL) spectroscopy. As-deposited a-Si0.8C0.2:H thin films contain a large amount of hydrogen and are amorphous. When annealing the films, the onset of Si crystallisation appears at 700 °C. For higher annealing temperatures, we observed SiC crystallites in addition to the Si nanocrystals (NCs). The crystallisation of SiC correlates with the occurrence of a strong PL band, which is strongly reduced after hydrogen passivation. Thus PL signal originates from the SiC matrix. Si NCs exhibit no PL yield due to their inhomogeneous size distribution.