Zone plates are diffractive optics commonly used in X-ray microscopes. Here, we present a wet-chemical approach for fabricating high aspect ratio Pd/Si zone plate optics aimed at the hard X-ray regime. A Si zone plate mold is fabricated via metal-assisted chemical etching (MACE) and further metalized with Pd via electroless deposition (ELD). MACE results in vertical Si zones with high aspect ratios. The observed MACE rate with our zone plate design is 700 nm/min. The ELD metallization yields a Pd density of 10.7 g/cm ${}^3$ , a value slightly lower than the theoretical density of 12 g/cm ${}^3$ . Fabricated zone plates have a grid design, 1:1 line-to-space-ratio, 30 nm outermost zone width, and an aspect ratio of 30:1. At 9 keV X-ray energy, the zone plate device shows a first order diffraction efficiency of 1.9%, measured at the MAX IV NanoMAX beamline. With this work, the possibility is opened to fabricate X-ray zone plates with low-cost etching and metallization methods.

中文翻译：

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用于制造硬 X 射线 Pd/Si 波带片的金属辅助化学蚀刻和化学沉积

波带片是 X 射线显微镜中常用的衍射光学器件。在这里，我们提出了一种湿化学方法，用于制造针对硬 X 射线区域的高纵横比 Pd/Si 波带片光学器件。Si 波带板模具通过金属辅助化学蚀刻 (MACE) 制造，并通过无电沉积 (ELD) 进一步用 Pd 金属化。MACE 产生具有高深宽比的垂直硅区。使用我们的波带板设计观察到的 MACE 速率为 700 nm/min。ELD 金属化产生的 Pd 密度为 10.7 g/cm3 ${}^3$ ，略低于理论密度12 g/cm3 ${}^3$ 。制作的波带片采用网格设计、1:1 线距比、30 nm 最外层波带宽度和 30:1 的纵横比。在 9 keV X 射线能量下，波带片装置显示出 1.9% 的一级衍射效率（在 MAX IV NanoMAX 光束线处测量）。通过这项工作，使用低成本蚀刻和金属化方法制造 X 射线波带片成为可能。