Interface roughness of Mo/Si soft X-ray multilayers

A series of Mo/Si multilayers were prepared by magnetron sputtering, with top layers being Mo layer and Si layer respectively. Periodic length of Mo/Si multilayers were determined by small angle X-ray diffraction. As fresh surfaces of Mo/Si multilayers with different period number were approximatively equal to the interface of the same multilayer, interface roughness change law of multilayers as layer number increases was studied by atomic force microscope. Soft X-ray reflectivity of Mo/Si multilayers were measured in National Synchrotron Radiation Laboratory. As the number of layers increases, interface roughness and peak reflectivity of multilayers first increase and then reduce．