Influence of substrate materials on nucleation and properties of iridium thin films grown by ald

Schmitt P, Beladiya V, Felde N, Paul P, Otto F, Fritz T, Tuennermann A, Szeghalmi AV (2021)

Publication Type: Journal article

Publication year: 2021

Journal

Coatings MDPI

Book Volume: 11

Pages Range: 1-23

Article Number: 173

Journal Issue: 2

DOI: 10.3390/coatings11020173

Abstract

Ultra-thin metallic films are widely applied in optics and microelectronics. However, their properties differ significantly from the bulk material and depend on the substrate material. The nucleation, film growth, and layer properties of atomic layer deposited (ALD) iridium thin films are evaluated on silicon wafers, BK7, fused silica, SiO2, TiO2, Ta2 O5, Al2 O3, HfO2, Ru, Cr, Mo, and graphite to understand the influence of various substrate materials. This comprehensive study was carried out using scanning electron and atomic force microscopy, X-ray reflectivity and diffraction, four-point probe resistivity and contact angle measurements, tape tests, and Auger electron spectroscopy. Within few ALD cycles, iridium islands occur on all substrates. Nevertheless, their size, shape, and distribution depend on the substrate. Ultra-thin (almost) closed Ir layers grow on a Ta2 O5 seed layer after 100 cycles corresponding to about 5 nm film thickness. In contrast, the growth on Al2 O3 and HfO2 is strongly inhibited. The iridium growth on silicon wafers is overall linear. On BK7, fused silica, SiO2, TiO2, Ta2 O5, Ru, Cr, and graphite, three different growth regimes are distinguishable. The surface free energy of the substrates correlates with their iridium nucleation delay. Our work, therefore, demonstrates that substrates can significantly tailor the properties of ultra-thin films.

Involved external institutions

Friedrich-Schiller-Universität Jena DE Germany (DE) Fraunhofer-Institut für Angewandte Optik und Feinmechanik (IOF) / Fraunhofer Institute for Applied Optics and Precision Engineering DE Germany (DE)

How to cite

APA:

Schmitt, P., Beladiya, V., Felde, N., Paul, P., Otto, F., Fritz, T.,... Szeghalmi, A.V. (2021). Influence of substrate materials on nucleation and properties of iridium thin films grown by ald. Coatings, 11(2), 1-23. https://doi.org/10.3390/coatings11020173

MLA:

Schmitt, Paul, et al. "Influence of substrate materials on nucleation and properties of iridium thin films grown by ald." Coatings 11.2 (2021): 1-23.

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