Performance of multilayer coatings in relationship to microstructure of metal layers. Characterization and optical properties of Mo/Si multilayers in extreme ultra-violet and x-ray ranges

Abstract

Here we present a development of multilayer-based optics for the extreme ultra-violet (EUV) and x-ray range. The authors discuss results of the study of optical performance of Mo/Si coatings with regard to the microstructure of metal layers, which was analysed by x-ray diffraction (XRD) and by transmission electron microscopy (TEM). We have demonstrated an ability to control the microstructure of the multilayers via optimization of the deposition process, which is important for various EUV and x-ray applications of multilayer optics.

Impact of B_4C co-sputtering on structure and optical performance of Cr/Sc multilayer X-ray mirrors

“…When grown with multilayer periodicities larger than Λ > 1.8 nm, both Cr and Sc spontaneously transforms into nanocrystalline layers. In general, crystallization is a serious issue since crystallites increase high spatial frequency interfacial roughness resulting in a poor reflectivity performance [14,15]. The impact is severe on optics requiring larger periodicities such as polarizers and broadband mirrors, essential to polarimetry and to shape attosecond pulses [16][17][18].…”

Development of Al-based multilayer optics for EUV

“…On the other hand, the optical properties of the materials in thin film or multilayer form depend on their microstructure. For instance, the state of a metal layer may change from amorphous to crystalline with the layer thickness [35]. It is known that the density of thin amorphous Mo films (<2 nm) can be as low as just 80 ÷ 90% with respect to the bulk Mo density [36].…”

Development and realization of non-periodic W/Si multilayer mirrors for 5–14keV X-ray plasma diagnostic

“…The other lines correspond to the calculated reflectivity of the (1-5), (6)(7)(8)(9)(10)(11)(12)(13)(14) and bi-layers, respectively.…”

“…For example, the flat shape between 10.5 and 12 keV is largely due to destructive and constructive mixing between first 5 bi-layers (which are responsible for peak no. 2) and the deep [6][7][8][9][10][11][12][13][14] bi-layers. In the same way, the reflectivity peak no.…”

“…This grazing angle is high enough to totally reflect X-rays lower than 5 keV, but not for higher photon energy. The use of non-periodic multilayer coated mirrors [5][6][7][8][9][10] is then necessary to enhance the bandwidth of the microscope's reflectivity.…”