Abstract

Roughness limits x-ray multilayer specular reflectance and contributes to scattering. Roughness is generally more important for multilayer mirrors than for total reflection mirrors, because multilayers operate at higher momentum transfer than total reflection mirrors, where the effects of roughness are more severe. As the multilayer period decreases, the effects of roughness increase, so that roughness is generally expected to play a significant role in limiting reflectance in the small d-spacing limit. Roughness in multilayers can originate from microstructural defects within the multilayer, or from propagation of roughness from the substrate into the multilayer. In any case, complete understanding of the roughness in multilayers cannot be obtained without first understanding the roughness spectrum ofthe substrates on which the multilayers are grown.

© 1994 Optical Society of America