Magnesium silicide based multilayers for soft X-ray optics

P. Boher, Ph Houdy, L. Hennet, Z. G. Li, A. Modak, D. J. Smith, M. Idir, T. Moreno, R. Barchewitz, M. Kühne, P. Müller, J. P. Delaboudiniere

Research output: Contribution to journalConference articlepeer-review

2 Scopus citations


Using a diode rf-sputtering technique, different magnesium silicide based multilayer systems have been deposited in very thin films for optical applications in the soft X-ray range. A detailed structural analysis of the different multilayers has been made using in-situ kinetic ellipsometry, ex-situ grazing X-ray reflection at the copper K-α line and transmission electron microscopy. The multilayer performances have been measured by synchrotron radiation at the magnesium K-α and L-α lines and related to the structural characteristics. For short wavelength, the W/Mg2Si system shows characteristics very similar to those of the more common W/Si system. Non-negligible interdiffusion and limited interface roughness allow the layer thicknesses to be reduced to very 1ow values. Well defined Bragg peaks are observed even when the double period is as low as 44 A. First Bragg peak reflectivity as high as 31% has been measured at 9.89 A for a multilayer with a double period equal to 84 A and a limited number of periods. This preliminary result is very promising for future applications in the field of X-ray fluorescence analysis. W/Mg2Si and Si3NΔ\Mg2Si multilayer have also been fabricated for use at higher wavelength around the Mg L-α line (286 Å). In the case of the W/Mg2Si system, the tungsten layers are crystallized due to their higher thickness and consequently the interface roughness is slightly higher. In spite of this, more than 20% reflectivity at the first Bragg peak has been measured at normal incidence on different W/Mg2Si samples, with a selectivity two times better than conventional Mo/Si mirrors (λ/δ λ ≃ 20). When we replace tungsten by a thin silicon nitride layer deposited by reactive sputtering, we increase the selectivity up to λ/δ λ ≃ 30, and the thermal stability is drastically improved (> 800°C).

Original languageEnglish (US)
Pages (from-to)502-519
Number of pages18
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jan 1 1992
EventMultilayer and Grazing Incidence X-Ray/EUV Optics 1991 - San Diego, United States
Duration: Jul 21 1991 → …

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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