Molybdenum-strontium multilayer mirrors for the 8-12-nm extreme-ultraviolet wavelength region

Mo-Sr multilayer mirrors were successfully deposited by dc-magnetron sputtering and characterized in situ with synchrotron radiation. Normal-incidence (3.6 degrees) reflectance of 23.0% at 8.8 nm, 40.8% at 9.4 nm, and 48.3% at 10.5 nm were measured before the samples were exposed to air. After exposure, as a result of the reactivity of Sr with oxygen and water vapor, the reflectance of these multilayers decreased rapidly. Attempts to use thin layers of C to passivate the surface of these Mo-Sr multilayers were unsuccessful. (C) 2001 Optical Society of America.