Design of Capping Layers on Mo/Si Multilayer
Mo/Si多层膜表面保护层设计

In order to improve the stability and lifetime of Mo/Si multilayers,the design of capping layers on Mo/Si multilayer was investigated.By analyzing the electrical field distribution of multilayer standing wave,both the thicknesses of capping layer and uppermost material layer can be optimized to enable the highest reflectivity.Theoretical calculation shows that a certain thickness of the capping layer always corresponds to an optimized uppermost material thickness.A theoretical reflectivity of 74.47% can be achieved at 13.36 nm for a typical Mo/Si multilayer consisting of 50 bi-layers at incident angle of 10°.When a 2.3nm Ru layer is added as capping layer onto the multilayer surface,meanwhile with the thickness of uppermost Si layer optimized to 3.93nm,the theoretical reflectivity will be improved to 75.20%.The research results indicate that the stability and performance of the multilayer can be improved by the optimized design of capping layers.