Development of Al-based multilayer optics for EUV

Evgueni Meltchakov (1) , Christophe Hecquet (1) , Marc Roulliay (2) , Sébastien de Rossi (1) , Yves Ménesguen (1) , Arnaud Jérôme (1) , Françoise Bridou (1) , Françoise Varniere (1) , Marie-Françoise Ravet-Krill (1) , Franck Delmotte (1)

1 Laboratoire Charles Fabry de l'Institut d'Optique / Scop
2 LIXAM - Laboratoire d'interaction du rayonnement X avec la matière

We report on the development of multilayer optics for the extreme ultra-violet (EUV) range. The optical performance of Al-based multilayer mirrors is discussed with regard to promising reflectivity and selectivity characteristics and the problems of the interfacial roughness for this type of multilayers. We demonstrate a possibility to reduce the average roughness by introducing additional metal layer (W or Mo) rather than depositing a buffer layer at each interface. We have prepared and tested Al/SiC, Al/W/SiC and Al/Mo/SiC multilayers of various periods for the spectral range from 15 to 40 nm, which is the range of increasing interest for high-order harmonic generation, synchrotron radiation and astrophysics. The structure of the three-component systems has been optimized in order to obtain the best reflectivity for each wavelength within the spectral range. We have shown that introduction of refractory metal in Al-based periodic stack can improve the optical performance of multilayer reflecting coatings designed for the EUV applications.

Domains: Optics [physics.optics]

Evgueni Meltchakov, Christophe Hecquet, Marc Roulliay, Sébastien de Rossi, Yves Ménesguen, et al.. Development of Al-based multilayer optics for EUV. Applied physics. A, Materials science & processing, 2010, 98, pp.111. ⟨10.1007/s00339-009-5445-2⟩. ⟨hal-00542261⟩