X-ray standing wave induced Compton and elastic scattering from thin periodic multilayer structures

Abstract

We report determination of structural parameters on angstrom length scale of nanostructured periodic multilayers using x-ray standing wave (XSW) enhanced elastic and Compton scattering. We show that the elastic scattered x-ray intensities emitted from the thin periodic multilayer structures, under strong XSW condition, are largely sensitive to the structural parameters of high-$z$ layers, whereas the Compton scattered intensities are sensitive to the parameters of low-$z$ layers. The utility of the methodology is demonstrated by analyzing two repetitive W/B${}_{4}$C multilayer structures with different surface-interface properties. The results are compared with those obtained using x-ray reflectivity and conventional x-ray standing wave fluorescence techniques. It is further shown that the Bragg angle can be derived with high accuracy (\ensuremath{\sim}0.002${}^{\ensuremath{\circ}}$) from the ratio of the scattering intensities, which in turn improves the accuracy of the derived multilayer periodicity. The method presents an opportunity to probe structures on angstrom length scale of any periodic multilayer structure comprising of low atomic number layers. Unlike the conventional XSW fluorescence measurements, the present method has an advantage that it permits the determination of structural parameters of both the high- and the low-$z$ layers independently.