Metal-assisted chemical etching and electroless deposition for fabrication of hard X-ray Pd/Si zone plates

Rabia Akan, Thomas Frisk, Fabian Lundberg, Hanna Ohlin, Ulf Johansson, Kenan Li, Anne Sakdinawat, Ulrich Vogt

Research output: Contribution to journalArticlepeer-review

3 Citations (SciVal)

Abstract

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/cm3, a value slightly lower than the theoretical density of 12 g/cm3. 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.

Original languageEnglish
Article number301
JournalMicromachines
Volume11
Issue number3
DOIs
Publication statusPublished - 2020

Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics

Keywords

  • Electroless deposition
  • High aspect ratio nanostructures
  • Metal-assisted chemical etching
  • X-ray diffractive optics
  • Zone plate

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