Nitridation and contrast of B4C/La interfaces and X-ray multilayer optics

Tsarfati, T.; Kruijs, R. W. E. van de; Zoethout, E.; Louis, Eric; Bijkerk, F.

doi:10.1016/j.tsf.2010.04.088

Cited by 31 publications

(38 citation statements)

References 37 publications

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“…Both La and B were deposited using DC magnetron sputtering. The LaN layer was created using nitrogen assisted growth similar to the approach described in [21]. The layer thicknesses were controlled by pre-calibrated deposition rates.…”

Section: Experiments Layout and Data Processingmentioning

confidence: 99%

Combined EUV reflectance and X-ray reflectivity data analysis of periodic multilayer structures

Yakunin¹,

Makhotkin²,

Nikolaev³

et al. 2014

Opt. Express

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We present a way to analyze the chemical composition of periodical multilayer structures using the simultaneous analysis of grazing incidence hard X-Ray reflectivity (GIXR) and normal incidence extreme ultraviolet reflectance (EUVR). This allows to combine the high sensitivity of GIXR data to layer and interface thicknesses with the sensitivity of EUVR to the layer densities and atomic compositions. This method was applied to the reconstruction of the layered structure of a LaN/B multilayer mirror with 3.5 nm periodicity. We have compared profiles obtained by simultaneous EUVR and GIXR and GIXR-only data analysis, both reconstructed profiles result in a similar description of the layered structure. However, the simultaneous analysis of both EUVR and GIXR by a single algorithm lead to a ∼ 2x increased accuracy of the reconstructed layered model, or a more narrow range of solutions, as compared to the GIXR analysis only. It also explains the inherent difficulty of accurately predicting EUV reflectivity from a GIXR-only analysis.

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Section: Experiments Layout and Data Processingmentioning

confidence: 99%

Combined EUV reflectance and X-ray reflectivity data analysis of periodic multilayer structures

Yakunin¹,

Makhotkin²,

Nikolaev³

et al. 2014

Opt. Express

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“…La and B are chemically reactive, 10,11 and studies have shown that La and B atoms tend to interdiffuse and form lanthanum borides at the interfaces even during deposition of La/B multilayers. 5,10,11 Recent studies by Makhotkin et al 5,16 suggest that the effective thickness of intermixed regions (i.e., boride interlayers) of as-deposited La/B multilayers (Λ ¼ 3.45 nm;…”

Section: Changes In La/b Multilayered Structuresmentioning

confidence: 99%

“…5,10,11 One of the methods to mitigate lanthanum boride formation is to replace the La layers with LaN, which is thermodynamically more stable. 5,10,11 One of the methods to mitigate lanthanum boride formation is to replace the La layers with LaN, which is thermodynamically more stable.…”

Section: Introductionmentioning

confidence: 99%

Diffusion-induced structural changes in La/B-based multilayers for 6.7-nm radiation

Nyabero

Kruijs

Yakshin

et al. 2014

J. Micro/Nanolith. MEMS MOEMS

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The thermal stability of La/B and LaN/B multilayers was investigated. The two multilayer systems were found to have comparable subångström period expansion upon annealing in the temperature range of 250°C to 400°C. For La/B multilayers, wide angle x-ray diffraction analysis revealed that the size of LaB 6 crystallites present did not change significantly upon thermal treatment. Using grazing incidence x-ray reflectometry, strong change in the internal structure due to interdiffusion at the interfaces of La/B multilayers was observed after annealing. This, coupled to the unchanged crystallinity, suggested the growth of amorphous lanthanum boride interlayers. At wavelength reflectance, measurements showed that as-deposited LaN/B multilayers had an enhanced optical contrast compared with La/B. During thermal loading, the rate of diffusion-induced reflectance decrease in LaN/B multilayers was slower than in La/B. The enhanced thermal stability of LaN/B was attributed to the slower growth of LaN-B interfaces compared with La-B.

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“…Similar interface widths were obtained in the case of a Mo/B 4 C multilayer, which was reported to show a 43% reduction in peak reflectance at normal incidence relative to the ideal theoretical case [9]. For La/B 4 C multilayers, interface imperfections have been reported to cause a reduction in peak reflectance over than 40% [12] being in fact the peak theoretical value around 0.65 and the experimental one around 0.40 at 6.7 nm in normal incidence reflectance and un-polarized light; in order to reduce the interface imperfections to some extent, the use of a nitridation process at the interfaces during film deposition has been suggested [17]. In both these previously realized structures, the study and control of the status of the interface was addressed, and specifically in [9] the Mo/B 4 C multilayer interface quality has been deeply studied.…”

Section: Resultsmentioning

confidence: 99%

Extreme ultraviolet multilayer for the FERMI@Elettra free electron laser beam transport system

Corso¹,

Zuppella²,

Windt³

et al. 2012

Opt. Express

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In this work we present the design of a Pd/B₄C multilayer structure optimized for high reflectance at 6.67 nm. The structure has been deposited and also characterized along one year in order to investigate its temporal stability. This coating has been developed for the beam transport system of FERMI@Elettra Free Electron Laser: the use of an additional aperiodic capping layer on top of the structure combines the high reflectance with filter properties useful in rejecting the fundamental harmonic when the goal is to select the third FEL harmonic.

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Nitridation and contrast of B4C/La interfaces and X-ray multilayer optics

Cited by 31 publications

References 37 publications

Combined EUV reflectance and X-ray reflectivity data analysis of periodic multilayer structures

Combined EUV reflectance and X-ray reflectivity data analysis of periodic multilayer structures

Diffusion-induced structural changes in La/B-based multilayers for 6.7-nm radiation

Extreme ultraviolet multilayer for the FERMI@Elettra free electron laser beam transport system

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