Regensburg 2025 – scientific programme
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DS: Fachverband Dünne Schichten
DS 9: Optical Analysis of Thin Films II
DS 9.6: Talk
Thursday, March 20, 2025, 11:30–11:45, H3
VUV ellipsometry for the determination of thin film optical constants — •Mattia Mulazzi1, Julian Plaickner2, Jörg Rappich3, Alexander Gottwald1, and Norbert Esser2 — 1Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587, Berlin, Germany — 2Technische Universität Berlin, Hardenbergstr. 36, 10623, Berlin, Germany — 3Helmholtz-Zentrum-Berlin für Materialien und Energie, Hahn-Meitner Platz 1, 14109 Berlin, Germany
Motivated by the purpose of determining the optical constants of thin films materials, we present our investigation method based on spectroscopic ellipsometry in the vacuum-ultraviolet spectral range using monochromatised synchrotron radiation. The measurements are characterised by low noise and high accuracy, both quantified according to state-of-the-art metrological procedures, and are well-suited to be fit by numerical methods to obtain the refractive index and the absorption coefficient in a non-parametric way, i.e., independent of the underlying physics of the material under investigation. We show exemplary measurements on surfaces of hydrogen-passivated Si, native SiO2 on Si, graphene on Si and the evaluation steps necessary to determine the optical constants from the measured data.
Keywords: UV ellipsometry; optical constants; synchrotron radiation