Introduction of Zr in nanometric periodic Mg/Co multilayers

TL;DR

This paper investigates the integration of zirconium into Mg/Co multilayers to enhance their optical performance in the EUV range, demonstrating improved reflectance and analyzing structural and optical properties.

Contribution

It introduces Zr into Mg/Co multilayers, providing experimental data and theoretical analysis on their optical performance for EUV applications.

Findings

Reflectance of 50% at 25.1 nm and 45° grazing incidence

Reflectance increases to 51.3% after annealing at 200°C

Material order within multilayers influences EUV reflectivity

Abstract

We study the introduction of a third material, namely Zr, within a nanometric periodic Mg/Co structure designed to work as optical component in the extreme UV (EUV) spectral range. Mg/Co, Mg/Zr/Co, Mg/Co/Zr and Mg/Zr/Co/Zr multilayers are designed, then characterized in terms of structural quality and optical performances through X-ray and EUV reflectometry measurements respectively. For the Mg/Co/Zr structure, the reflectance value is equal to 50% at 25.1 nm and 45deg of grazing incidence and reaches 51.3% upon annealing at 200deg C. Measured EUV reflectivity values of tri-layered systems are discussed in terms of material order within a period and compared to the predictions of the theoretical model of Larruquert. Possible applications are pointed out.