Application of Tungsten as a Barrier Layer in Sc/Si Multilayer X-ray Mirrors

Authors Yu.P. Pershyn1 , V.S. Chumak1, E.N. Zubarev1 , A.Yu. Devizenko1 , V.V. Kondratenko1 , J.F. Seely2

1National Technical University “Kharkiv Polytechnic Institute”, 2, Kyrpychov Str., 61002 Kharkiv, Ukraine

2Naval Research Laboratory, Space Science Division, Code 7674, Washington D.C. 20375, USA

Issue Volume 10, Year 2018, Number 2
Dates Received 15 January 2018; revised manuscript received 25 April 2018; published online 29 April 2018
Citation Yu.P. Pershyn, V.S. Chumak, E.N. Zubarev, et al., J. Nano- Electron. Phys. 10 No 2, 02032 (2018)
PACS Number(s), 61.43.Dq, 68.65.Ac, 41.50. + h, 07.85.Fv
Keywords Multilayer X-ray mirror, Interface zone mixing, Barrier layer, Zone contraction, Reflectivity growth.

By methods of hard X-ray diffraction (λ = 0.154 nm), cross-sectional transmission electron microscopy and soft X-ray (λ = 25-50 nm) reflectometry the barrier characteristics of tungsten layers of tW = 0.1-2.1 nm thick in Sc/W/Si multilayer X-ray mirrors (MXMs) fabricated with DC magnetron sputtering are studied. Tungsten layers of 0.6-0.8 nm thick are shown to separate Sc and Si layers and prevent formation of ScSi intermixed zones. Tungsten interacts with silicon forming thinner silicide layers in comparison with original ScSi interlayers in Sc/Si MXMs without barriers. Barrier layers are not continuous at tW < 0.5 nm when deposited on Sc layers. Introduction of W-layers 0.3-0.8 nm thick increases reflectivity (λ ≈ 38 nm) of Sc/W/Si MXMs at least by factor of 2.5 maximizing at R ≈ 25 % at normal incidence (α = 5°). Further improvements in technology and reflectivity are discussed.

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