SMOOTHING OF INTERFACES IN ULTRATHIN MO SI MULTILAYERS BY ION-BOMBARDMENT/

Mo/Si multilayers with a bilayer thickness of 2.6 nm are produced by e lectron beam evaporation in ultrahigh vacuum for soft X-ray optical ap plications. High reflectivities resulting from constructive interferen ce in the stack are limited by the optical constants of the materials and by the quality of the interfaces. Smoothing of the boundaries is o btained by bombardment of the deposited layers with Ar+ ions. The smoo thness of the interfaces is controlled during the deposition by in sit u measurement of the reflectivity for the C K radiation of the stack a nd after completion of the stack by means of a grazing X-ray reflectio n set-up with Cu Kalpha radiation. The soft X-ray reflectivity is meas ured with a laser-induced plasma light source.