(1) Laboratoire Charles Fabry de l’Institut d’Optique, CNRS, Univ. Paris Sud, Campus Polytechnique, RD128, 91127 Palaiseau Cedex, France;(2) Institut des NanoSciences de Paris, Campus Boucicaut, 140 rue de Lourmel, 75015 Paris, France
Abstract:
Processes undergoing in Sc/Si multilayer X-ray mirrors (MXMs) with periods of ∼27 nm and barrier layers of CrB20.3- and 0.7-nm thick within the temperature range of 420–780 K were studied by methods of small-angle X-ray reflectivity
(λ=0.154 nm) and cross-sectional transmission electron microscopy. All layers with the exception of Sc ones are amorphous. Barrier
layers are stable at least up to a temperature of 625 K and double the activation energy of diffusional intermixing at moderate
temperatures. Introduction of barriers improves the thermal stability of Sc/Si MXMs at least by 80 degrees. Diffusion of Si
atoms through barrier layers into Sc layers with formation of silicides was shown to be the main degradation mechanism of
MXMs. A comparison of the stability for Sc/Si MXMs with different barriers published in the literature is conducted. The ways
of further improvement of barrier properties are discussed.