Growth and optical performance of short-period W/Al and polished W/Si/Al/Si multilayers

Dennis IJpes*, Andrey Yakshin, J.M. Sturm, Marcelo Ackermann

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
15 Downloads (Pure)

Abstract

Short-period multilayer mirrors are used in wavelength-dispersive x-ray fluorescence to reflect and disperse elements in the O-Kα– Al-Kα range. In this work, we investigated sputter-deposited 2.5 nm W/Al with 20 periods. Our results show that W/Al is a poor reflector due to a combination of high interfacial roughness and strong W–Al intermixing. To address this, we introduced 0.5 nm Si seed layers at the W-on-Al and Al-on-W interfaces each consecutive period, while reducing the Al thickness from ∼2.0 to ∼1.0 nm. The Si seed layers significantly reduced interfacial roughness and W–Al intermixing, which led to an increase in the reflectance of the first Bragg peak at λ = 0.154 nm. To further reduce interfacial roughness, ion beam polishing of the top Si layer was applied at each period. The resulting structure of W/Si/Al/Si with ion beam polishing showed that the reflection coefficient of the first Bragg peak at λ = 0.154 nm was comparable to that of standard W/Si. These findings demonstrate the effectiveness of seed layers combined with polishing techniques in synthesizing smooth, high-reflectance multilayers containing two materials that are otherwise challenging to synthesize.
Original languageEnglish
Article number155301
Number of pages12
JournalJournal of Applied Physics
Volume134
Issue number15
Early online date17 Oct 2023
DOIs
Publication statusPublished - 21 Oct 2023

Keywords

  • UT-Hybrid-D

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