title: Structural properties of subnanometer thick Y layers in extreme ultraviolet multilayer mirrors.
abstract: We studied the structure and optical properties of B(4)C/Mo/Y/Si multilayer systems. Using extended x-ray absorption fine structure measurements at the Y and Mo K-edge, the structure of the subnanometer thick Y layer and the underlying Mo layer were analyzed. It was found that even a 0.2 nm thick Y layer significantly reduced silicon diffusion toward Mo, thus reducing Mo silicide formation. Hard x-ray reflectometry showed that the difference in average interface roughness of the B(4)C/Mo/Y/Si multilayer structure compared to Mo/Si and B(4)C/Mo/B(4)C/Si multilayer structures was negligible. Soft x-ray reflectometry showed optical improvement of B(4)C/Mo/Y/Si with respect to Mo/Si and B(4)C/Mo/B(4)C/Si multilayer structures.
authors.affiliation: Fundamental Research on Matter Institute, Dutch Institute for Fundamental Energy Research, Nieuwegein, The Netherlands. j.bosgra@differ.nl
authors.forename: Jeroen
authors.initials: J
authors.lastname: Bosgra
authors.forename: Erwin
authors.initials: E
authors.lastname: Zoethout
authors.forename: Ad M J
authors.initials: AM
authors.lastname: van der Eerden
authors.forename: Jan
authors.initials: J
authors.lastname: Verhoeven
authors.forename: Robbert W E
authors.initials: RW
authors.lastname: van de Kruijs
authors.forename: Andrey E
authors.initials: AE
authors.lastname: Yakshin
authors.forename: Fred
authors.initials: F
authors.lastname: Bijkerk