Fabrication and Characterization of Multilayer Zone Plate for Hard X-Rays

Abstract

A zone plate for 8 keV X-rays with alternative WSi2 and C layers was fabricated using a DC planer magnetron sputtering. The zone plate had 20 pairs of a high aspect ratio for hard X-rays. Its thickness was about 50 µm. An X-ray interference pattern through the zone plate was observed using monochromated synchrotron X-rays, and a focusing property of the zone plate was confirmed. The focal length was about 67 mm and the spot size (FWHM) was smaller than 8 µm.

Development of Multilayer Laue Lenses; (1) Linear Type

“…It would be difficult in principle to fabricate features smaller than ~10 nm and to get a higher aspect ratio than ~20 with conventional electron beam lithography. To overcome these difficulties, a multilayer (or sputtered-sliced) zone plate was proposed by Rudolph et al [1] and has been developed by a few groups [2][3][4]. However, the smaller the zone width becomes, the lower the local diffraction efficiency becomes due to the volume effect.…”

Multilayer Fresnel Zone Plate with High-Diffraction Efficiency: Application of Composite Layer to X-Ray Optics

“…Hart et al (Hart et al, 1966) and Rudolph et al (Rudolph et al, 1981) proposed the concept of the ML-FZP. WSi 2 /C FZP and Cu/Al FZP were subsequently developed and tested by Saitoh et al (Saitoh et al, 1988;Saitoh et al, 1989) and Bionta et al (Bionta et al, 1989;Bionta et al 1990), respectively. However, these experiments did not achieve focusing with submicron spot size.…”

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Upgrading multilayer zone plate technology for hard x-ray focusing

“…However, zone structures with such high aspect ratios cannot currently be fabricated by electron beam lithography (EBL), which is generally used for FZP fabrication. Multilayer zone plate technology (MZP), first proposed by Rudolph et al (1981) [3] and developed by Saito et al (1989) [4] and Kamijo et al (2009) [5], is an alternative approach to overcome this problem. The MZP is fabricated by stacking alternate layers of MoSi2 and Si on a cylindrical substrate (glass fiber) and reducing the crosssection of the layers to an optimal thickness.…”