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In this paper, the effect of nitrogen flow rates on the physical properties of thin TaN films deposited on glass and silicon substrates using reactive DC magnetron sputtering was experimentally studied. The structural and optical properties of the films were evaluated by X-ray diffraction, atomic force microscopy, and optical spectrophotometry. X-ray diffraction patterns revealed that the phase composition evolves from pure metallic α-Ta body centred cubic to tantalum nitride δ-TaN rock-salt structure. However, when the N2 flow rate exceeds 2 sccm, the films will show a poorly defined crystallization composed of mixture of fcc TaN phase and amorphous phases. Scanning electron microscopy and atomic force microscopy images revealed that the films deposited at high nitrogen flow rate possess smooth surface, good quality and lower roughness. The optical characterisation confirms that they are two groups of samples. The first have an metallic character with high reflectance and the second group are more transparent with an dielectric character with an absorption gap around 1.8 eV.

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This article deals with an early growth study of hydrogenated and non-hydrogenated amorphous silicon carbide thin films (a-SiC:H, a-SiC). Sample have been elaborated at room temperature by a new configuration (Up-down) sputtering d.c. magnetron technique, using a 6H-SiC polycrystalline target onto p-Si(100) and glass substrates. The infrared spectra reveal the existence of a band located at 740 cm -1 , which corresponds to Si-C stretching mode of amorphous silicon carbide. The SIMS and AES profiles show a c-face for both a-SiC:H and a-SiC. Films elaborated with this configuration (Up-down) are stoichiometric, with a ratio 28 Si/ 12 C = 0.95, compared to the one elaborated with conventional configuration (Down-up), which is 1.75. The optical gap is 1.84 eV and 1.48 eV for a-SiC: H and aSiC respectively. This behavior of optical gap may be related to the hydrogen concentration present in the films or other impurities inducing such a decrease in optical gap.

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