The influence of a carbon barrier layer to improve the reflectivity of Cr/Ti multilayers, intended to be used in the water window wavelength regime, is investigated. Specular grazing‐incidence X‐ray reflectivity results of Cr/Ti multilayers with 10 bilayers show that interface widths are reduced to ∼0.24 nm upon introduction of a ∼0.3 nm C barrier layer at each Cr‐on‐Ti interface. As the number of bilayers increases to 75, a multilayer with C barrier layers maintains almost the same interface widths with no cumulative increase in interface imperfections. Using such interface‐engineered Cr/C/Ti multilayers, a remarkably high soft X‐ray reflectivity of ∼31.6% is achieved at a wavelength of 2.77 nm and at a grazing angle of incidence of 16.2°, which is the highest reflectivity reported so far in the literature in this wavelength regime. Further investigation of the multilayers by diffused grazing‐incidence X‐ray reflectivity and grazing‐incidence extended X‐ray absorption fine‐structure measurements using synchrotron radiation suggests that the improvement in interface microstructure can be attributed to significant suppression of inter‐diffusion at Cr/Ti interfaces by the introduction of C barrier layers and also due to the smoothing effect of the C layer promoting two‐dimensional growth of the multilayer.

中文翻译：

---

Cr / Ti多层膜与C阻挡层的界面改性，以提高水窗状态下的反射率

研究了旨在用于水窗波长范围的碳阻挡层对改善Cr / Ti多层膜反射率的影响。具有10个双层的Cr / Ti多层膜的镜面掠入射X射线反射率结果表明，在每个Cr-Ti-Ti界面上引入约0.3 nm的C势垒层后，界面宽度减小至约0.24 nm。随着双层数增加到75，带有C势垒层的多层将保持几乎相同的界面宽度，而界面缺陷不会累积增加。使用这种由界面工程设计的Cr / C / Ti多层膜，在2.77 nm的波长和16.2°的掠入射角下可获得高达31.6％的非常高的软X射线反射率，这是据报道的最高反射率在这个波长范围内，在文献中还远远没有。