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  Chkhalo, N.I.; Künstner, S.; Polkovnikov, V.N.; Salashchenko, N.N.; Schäfers, F.; Starikov, S.D.: High performance La/B₄C multilayer mirrors with C-barrier layers for the next generation lithography. Applied Physics Letters 102 (2013), p. 011602/1-3

10.1063/1.4774298

Abstract:
Results on optimization and manufacturing of La/B4C multilayers are reported. Such mirrors are promising optical elements for the development of the next generation of nano-lithography at an operation wavelength of 6.7 nm. A near-normal incidence reflectivity of up to 58.6% has been measured at the BESSY-II soft x-ray reflectometer beamline. This is the highest reflectivity measured so far at this wavelength. The potential to further increase the reflectivity of the multilayers is discussed