Design and fabrication of soft X-ray multilayer for broadband reflection

A random method used for improving light throughput of a soft X-ray multilayer has been developed in the 18–20 nm spectral region, based on the traditional theory of periodic multilayer, and an 8% gain in integrated reflectance is obtained. The ensemble calculation is presented at the same time, and the multilayer is fabricated by magnetron sputtering. Finally low-angle X-ray diffraction and reflectance comparative measurement are used for testing the multilayer. The results demonstrate that layer thickness disorder yields band broadening and increased integrated reflectance in the spectral range with respect to periodic multilayer, but is accompanied by a reduction in reflectance peak. Layer thickness disorder makes it more difficult to fabricate broadband multilayer, and improving the techniques of layer thickness control is the keystone of experiments.