DIFFUSE-X-RAY SCATTERING OF AMORPHOUS MULTILAYERS

We present a new method to measure the diffuse scattering of amorphous multilayers. In contrast to conventional scans, that all take place i n the plane of reflection, in this out-of-plane scattering geometry th e accessible range in parallel momentum transfer Q(parallel-to) is not limited by the sample surface. We can therefore record data continuou sly from very small Q(parallel-to) up to Q(parallel-to) congruent-to 2 pi/lambda, holding Q(perpendicular-to) constant at the same time. We t hereby obtain a scattering factor S(Q) of our sample, that can easily be attributed to diffuse scattering at rough interfaces or amorphous b ulk, respectively. In the case of the W/C amorphous multilayer studied here, the data show that the contribution of amorphous scattering is less than 2% up to about Q(parallel-to) = 0.1 angstrom-1, and becomes dominant only in the wide angle region. This allows to draw the conclu sion, that the Bragg sheets observed in the vicinity of the specular c ondition are mainly due to conformal roughness of the multilayer inter faces.