SURVEY OF TI-BASED, B-BASED, AND Y-BASED SOFT X-RAY-EXTREME ULTRAVIOLET MULTILAYER MIRRORS FOR THE 2 TO 12-NM WAVELENGTH REGION

We have performed an experimental investigation of Ti-, B4C-, B-, and Y-based multilayer mirrors for the soft x-ray-extreme ultraviolet (XUV ) wavelength region between 2.0 and 12.0 nm. Eleven different material pairs were studied: Ti/Ni, Ti/Co, Ti/Cu, Ti/W, B4C/Pd, B/Mo, Y/Pd, Y/ Ag, Y/Mo, Y/Nb, and Y/C. The multilayers were sputter deposited and we re characterized with a number of techniques, including low-angle x-ra y diffraction and normal incidence XUV reflectometry. Among the Ti-bas ed multilayers the best results were obtained with Ti/W, with peak ref lectances up to 5.2% at 2.79 nm at 61 degrees from normal incidence. T he B4C/Pd and B/Mo multilayer mirrors had near-normal incidence (5 deg rees) peak reflectances of 11.5% at 8.46 nm and 9.4% at 6.67 nm, respe ctively, whereas a Y/Mo multilayer mirror had a maximum peak reflectan ce of 25.6% at 11.30 nm at the same angle. The factors limiting the pe ak reflectance of these different multilayer mirrors are discussed. (C ) 1996 Optical Society of America