High-frequency multilayer diffraction Si-gratings with a low blaze angle – fabrication

High-frequency X-ray diffraction gratings with a groove density of 2500 mm$^{-1}$ and a low blaze angle were fabricated on Si(111)1.8$^\circ$ wafers using electron beam lithography and wet anisotropic etching. A multilayer Mo/Be coating consisting of 40 bilayers for a wavelength of 11.3 nm was deposited by magnetron sputtering. The groove profile during the fabrication of the gratings was monitored using atomic force microscopy and scanning electron microscopy. The averaged and random groove profiles and high- and mid-frequency roughness values of the best diffraction gratings obtained with atomic force microscopy will be used for subsequent simulation of the diffraction efficiency using the PCGrate$^{\mathrm{TM}}$ code.