Research Article

Atomic layer deposition for hafnium oxide-based meta-optics in the ultraviolet spectral range

¹ Friedrich-Schiller-University, Institute of Applied Physics, Albert-Einstein-Strasse 15, 07745 Jena, Germany
² Fraunhofer Institute for Applied Optics and Precision Engineering IOF, Albert-Einstein-Str. 7, 07745 Jena, Germany
³ Ernst-Abbe-Hochschule Jena, University of Applied Sciences, Carl-Zeiss-Promenade 2, 07745 Jena, Germany
⁴ Karlsruhe Institute of Technology (KIT), Kaiserstraße 12, 76131 Karlsruhe, Germany
⁵ Department of Plasma Physics and Technology, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czechia
⁶ TU Braunschweig, Institute of Semiconductor Technology, Hans-Sommer-Str. 66, 38106 Braunschweig, Germany
⁷ TU Braunschweig, LENA Laboratory for Emerging Nanometrology, Langer Kamp 6a/b, 38106 Braunschweig, Germany
⁸ Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 30 January 2026
Accepted: 4 April 2026

Abstract

Hafnium oxide (HfO₂) is a high-index dielectric material of growing importance for optical coatings and meta-optical components operating from the ultraviolet (UV) to the visible spectral range. Its large bandgap, chemical stability, and compatibility with established semiconductor processes make it particularly attractive for applications requiring low absorption and precise thickness control. In this work, we investigate the optical material properties of HfO₂ thin films deposited by plasma-enhanced atomic layer deposition (PEALD). The complex refractive index is experimentally determined over a broad spectral range extending from the vacuum ultraviolet (140 nm) to the visible (600 nm) by combining spectroscopic ellipsometry, spectrophotometry, and infrared ellipsometry. A comprehensive dispersion model is employed to extract consistent optical constants and thickness values. The results highlight the suitability of PEALD-grown HfO₂ films for advanced optical and meta-optical applications.