X-ray scattering study of interfacial roughness correlation in Mo/Si multilayers fabricated by ion beam sputtering

Specular and diffuse x-ray scattering are used to probe the mesoscopic stru cture of interfaces within two 30-period Mo/Si superlattices, grown on sili con and glass substrates by ion beam sputtering. The data are evaluated qua litatively and quantitatively on the basis of a distorted-wave Born approxi mation, which includes a correlating behavior of interface roughness in bot h the lateral and vertical directions. Different initial conditions of the substrate's surface result in distinguishable characters of roughness repli cations in the direction of growth. The average value, lateral correlation and fractal dimension of roughness are found to be different in the two sam ples, which leads to differences in the reflective properties of multilayer mirrors. (C) 2000 American Institute of Physics. [S0021-8979(00)05810-2].