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DS: Dünne Schichten
DS 9: Functional thin films II
DS 9.3: Talk
Tuesday, March 28, 2006, 11:45–12:00, GER 37
Growth and stress evolution of reactively sputtered ZrN films — •Patrick Karimi and Matthias Wuttig — I. Institute of Physics (1A), Aachen University, 52056 Aachen, Germany
In this study we present the growth, in-situ stress evolution as well as optical properties of DC sputtered ZrN thin films grown on Si substrates. The variation of N2 flow during the Zr deposition processes results in ZrN with different properties. Film characterization has been done by Rutherford backscattering spectroscopy (RBS), x-ray diffraction (XRD), x-ray reflectometry (XRR), in-situ stress measurements and spectroscopic ellipsometry. From the deposition characteristics it has been shown that ZrN exhibits a weak hysteresis. The deposition rate initially increases and then characteristically drops with increasing N2 flow. RBS and GXRD studies show structure evolution from hexagonal Zr, to cubic understoichiometric ZrN and stoichiometric ZrN films. We have shown that the drop in the sputter rate by 41.5 % after the transition point is accompanied by significant drop of the (111) texture coefficient while (200) texture coefficient starts to rise sharply. Film thickness, density, surface and interface roughness were deduced from XRR experiments. The stress evolution has been explained in-terms of the bombardment and subplantation mechanism, which induces the observed increase in cell volume. Optical constants of ZrN films have been investigated by spectroscopic ellipsometry and the results are correlated with RBS and XRR experiments.