| DC reactive magnetron sputtering was used for the deposition of Zr-Si-N thin films. Four series of samples have been deposited at various substrate temperatures TS: room temperature (RT), 240 °C, 440 °C and 640 °C. The total pressure was 0.6 Pa. Depending on TS, different N2 partial pressures are required for obtaining nearly stoiciometric ZrN films. The nitrogen partial pressure was kept constant for each series at 5%, 12.5%, 37.5%, and 65%, respectively. Si content (CSi) was varied in each series by changing the power applied on the Si target, whereas that on Zr target was kept constant. Besides the standard characterization techniques, electrical resistivity measurements have been performed between 20 and 300K. The results of theoretical fitting using the grain boundary scattering model show that the transport properties change with Si addition from a moderated damping regime to a strong damping regime. The optical properties of the Zr-Si-N films with CSi ≤ 10 at.% can be well explained by straight forward modeling of their dielectric functions by a set of Drude-Lorentz oscillators. In this model, the Drude damping factor Γp (or time relaxation of the free carriers) is mainly related to the film morphology, i.e. the crystallite size and the nature of the grain boundary barrier. The electron transmission probability G (obtained from fitting of resistivity measurements), the Si coverage on the ZrN grain surfaces (obtained from structural model calculation) and the Drude damping factor Γp (obtained from fitting the dielectric function) are well correlated. |
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