Thermal Stability of Normal Incidence Multilayer Mirrors for the X-Ray Wavelength near Carbon K-Edge

Annealing effects in the short-period multilayers Cr₃C₂/C, TiC/C, Cr₃C₂/(B + C), and CrB₂/C were studied in a wide temperature range ~200–1200°C by x-ray scattering and cross-sectional electron microscopy. It was shown that the thermodynamic equilibrium of the layer materials at their interfaces and stabilization of layer structure by impurities and heat treatment are effective approaches to short-period multilayers with enhanced thermal stability of their structure and optical properties.