Study of Nb-based material combination multilayer for X-ray applications

摘要

Nb-based Multilayer Laue Lens (MLL) shows high efficiency and great focusing ability at energy around 18keVtheoretically. In this paper, to study the potential of Nb-based material combinations in nano-focusing, a series of Nbbasedmultilayers: Nb/Si, Nb/Al and Nb/Al(1%wtSi) are fabricated by using direct-current magnetron sputteringtechnology. Real-time stress measurement is utilized for stress analysis while the quality of multilayers is characterizedby XRR and XRD. As a result, Nb presents a crystal state in the Nb/Si multilayer, and shows an asymmetric distributionat the interfaces. Both Nb films and Si films are in a strong compressive stress state, leading to a large total stress.Studies on the Nb/Al and Nb/Al(1%wtSi) multilayers show that both Al and Nb were crystalline under pure Arsputtering conditions, resulting in large film interface width and poor film quality. The addition of 10% concentration ofnitrogen in reactive sputtering can effectively suppress the crystallization of Al and change the crystalline state of Nb.However, the introduction of nitrogen greatly increased the compressive stress of Nb film, resulting in larger stress.