A structural characterization of W/Si multilayers using X-ray reflectivity (XRR), scanning transmission electron microscopy (STEM) and grazing-incidence small-angle X-ray scattering (GISAXS) is presented. STEM images revealed lateral, periodic density fluctuations in the Si layers, which were further analysed using GISAXS. Characteristic parameters of the fluctuations such as average distance between neighbouring fluctuations, average size and lateral distribution of their position were obtained by fitting numerical simulations to the measured scattering images, and these parameters are in good agreement with the STEM observations. For the numerical simulations the density fluctuations were approximated as a set of spheroids distributed inside the Si layers as a 3D paracrystal (a lattice of spheroids with short-range ordering but lacking any long-range order). From GISAXS, the density of the material inside the density fluctuations is calculated to be 2.07 g cm−3 which is 89% of the bulk value of the deposited layer (2.33 g cm−3).

中文翻译：

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W/Si多层膜中相关横向密度涨落的掠入射小角X射线散射研究

提出了使用 X 射线反射率 (XRR)、扫描透射电子显微镜 (STEM) 和掠入射小角 X 射线散射 (GISAXS) 来表征 W/Si 多层膜的结构。STEM 图像揭示了硅层中的横向周期性密度波动，并使用 GISAXS 对其进行了进一步分析。通过对测量的散射图像进行数值模拟，得到了波动的特征参数，例如相邻波动之间的平均距离、平均尺寸和位置的横向分布，这些参数与STEM观测结果吻合良好。对于数值模拟，密度波动被近似为一组分布在 Si 层内的 3D 准晶体球体（具有短程有序但缺乏任何长程有序的球体晶格）。根据 GISAXS，计算出密度波动范围内材料的密度为 2.07 g cm−3这是沉积层体积值的 89% (2.33 g cm−3）。