Open AccessImproving the soft X‐ray reflectivity of Cr/Ti multilayers by co‐deposition of B 4 C
Author(s) -
Zhu Jingtao,
Zhang Jiayi,
Li Haochuan,
Tu Yuchun,
Chen Jinwen,
Wang Hongchang,
Dhesi Sarnjeet S.,
Cui Mingqi,
Zhu Jie,
Jonnard Philippe
Publication year - 2020
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577520011741
Subject(s) - materials science , water window , x ray photoelectron spectroscopy , x ray reflectivity , reflectometry , deposition (geology) , reflectivity , analytical chemistry (journal) , x ray , thin film , crystallization , wavelength , crystallography , optics , optoelectronics , chemistry , nanotechnology , nuclear magnetic resonance , time domain , paleontology , physics , organic chemistry , chromatography , sediment , computer science , computer vision , biology
The `water window', covering 2.4–4.4 nm, is an important wavelength range particularly essential to biology research. Cr/Ti multilayers are one of the promising reflecting elements in this region because the near‐normal‐incidence reflectivity is theoretically as high as 64% at 2.73 nm. However, due to multilayer imperfections, the reported reflectivity is lower than 3% for near‐normal incidence. Here, B and C were intentionally incorporated into ultra‐thin Cr/Ti soft X‐ray multilayers by co‐deposition of B 4 C at the interfaces. The effect on the multilayer structure and composition has been investigated using X‐ray reflectometry, X‐ray photoelectron spectroscopy, and cross‐section electron microscopy. It is shown that B and C are mainly bonded to Ti sites, forming a nonstoichiometric TiB x C y composition, which hinders the interface diffusion, supresses the crystallization of the Cr/Ti multilayer and dramatically improves the interface quality of Cr/TiB x C y multilayers. As a result, the near‐normal‐incidence reflectivity of soft X‐rays increases from 4.48% to 15.75% at a wavelength of 2.73 nm.