A series of Mo/Si multilayers with the same periodic length and different periodic number were prepared by magnetron sputtering, whose top layers were respectively Mo layer and Si layer. Periodic length and interface roughness of Mo/Si multilayers were determined by small angle X-ray diffraction (SAXRD). Surface roughness change curve of Mo/Si multilayer with increasing layer number was studied by atomic force microscope (AFM). Soft X-ray reflectivity of Mo/Si multilayers was measured in National Synchrotron Radiation Laboratory (NSRL). Theoretical and experimental results show that the soft X-ray reflectivity of Mo/Si multilayer is mainly determined by periodic number and interface roughness, surface roughness has little effect on reflectivity.

由于界面互扩散的存在，实际的超薄多层膜很难具有清晰的界面结构．假设超薄多层膜为具有周期性梯度折射率的多层膜结构，用直线模型和余弦模型模拟了周期性梯度折射率多层膜的软X射线反射率．结果证明，折射率余弦渐变的多层膜虽然不具有清晰的界面，但它同样具有很高的反射率．

建立了一台使用气体靶激光等离子体光源的软X射线反射率计,并给出了使用该反射率计测量软X射线多层膜反射率的方法.与金属靶等离子体光源相比,由于使用了气体靶等离子体光源,该反射率计具有低碎屑、可长期连续运行等优点.针对单色仪的二级光谱对反射率测量结果产生的影响,提出了修正方法.并用此方法对实测的工作波长为17.1 nm软X射线多层膜的反射率曲线进行了修正.