Investigation of the thermal stability of Mg/Co periodic multilayers for EUV applications

• Published in: Applied physics. A, Materials science & processing Vol. 106; no. 3; pp. 737 - 745
• Main Authors: Hu, M.-H., Le Guen, K., André, J.-M., Zhou, S. K., Li, H. C., Zhu, J. T., Wang, Z. S., Meny, C., Mahne, N., Giglia, A., Nannarone, S., Estève, I., Walls, M., Jonnard, P.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.03.2012; Springer; Springer Verlag
• Subjects: Characterization and Evaluation of Materials; Condensed Matter; Condensed Matter Physics; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Machines; Manufacturing; Metals and metallic alloys; Nanotechnology; Optical and Electronic Materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Optics; Other; Physics; Physics and Astronomy; Processes; Surfaces and Interfaces; Thin Films; Nuclear Magnetic Resonance Spectrum; Nuclear Magnetic Resonance; Electron Energy Loss Spectroscopy; Reflectivity Curve; Scan Transmission Electron Microscopy; Scanning electron microscopy; Annealing; Cobalt; Thermal stability; Multilayers; Electron energy loss spectra; Reflection spectrum; Temperature effects; Magnesium; Nuclear magnetic resonance; X-ray emission spectra; Scanning transmission electron microscopy; Microstructure; Extreme ultraviolet spectra; scanning electron microscopy; multilayer; nuclear magnetism resonance spectroscopy; electron energy loss spectroscopy; EUV reflectivity; Mg; scanning transmission electron microscopy; annealing; interface; Co; x-ray emission spectroscopy
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-011-6681-9

We present the results of the characterization of Mg/Co periodic multilayers and their thermal stability for the EUV range. The annealing study is performed up to a temperature of 400 ∘ C. Images obtained by scanning transmission electron microscopy and electron energy loss spectroscopy clearly show a good quality of the multilayer structure. The measurements of the EUV reflectivity around 25 nm (∼49 eV) indicate that the reflectivity decreases when the annealing temperature increases above 300 ∘ C. X-ray emission spectroscopy is performed to determine the chemical state of the Mg atoms within the Mg/Co multilayer. Nuclear magnetic resonance used to determine the chemical state of the Co atoms and scanning electron microscopy images of cross sections of the Mg/Co multilayers reveal changes in the morphology of the stack from an annealing temperature of 305 ∘ C. This explains the observed reflectivity loss.