Structure of Sc/Si multilayer mirrors in as-deposited state and after annealing

Article type: Research Article

Authors: Fedorenko, A.I. | Pershin, Yu.P. | Poltseva, O.V. | Ponomarenko, A.G. | Sevryukova, V.S. | Voronov, D.L. | Zubarev, E.N.

Affiliations: Department of Physics of Metals and Semiconductors, Kharkiv State Polytechnic University, Frunze Street 21, Kharkiv 310002, Ukraine. E-mail: fedor@kpi.kharkov.ua

Note: [] 15 Carlson Street, Coventry, RI 02816, USA. Tel.: +1 401 823 0244; E-mail: aifedorenko@ yahoo.com

Abstract: The structure, phase and chemical compositions of Sc/Si multilayer XUV mirrors (MLMs) were studied by cross-sectional electron microscopy, hard X-ray (\lambda =0.154 nm) diffraction and X-ray microanalysis. In as-deposited state Sc/Si MLMs with periods D>18 nm consist of polycrystalline Sc- and amorphous Si-layers divided by intermixed amorphous zones (IAZs) with thickness around \sim 3 nm on each interface. A few percent of oxygen in Sc layers is responsible for its FCC structure instead of stable HCP one. According to simulations, composition and density of IAZs are close to silicide ScSi. Integral diffusivity of Sc-Si alloys during formation of IAZs in the process of multilayer growth was 10^{-14}--10^{-15} cm^2/s. Deposited by e-beam evaporation Sc/Si MLMs have interface roughness as high as 2.5 nm exceeding by a factor of two those produced by magnetron technology. Heating up to 500^{\circ}C is accompanied by planar broadening of IAZs with substantial period decrease, reaching up to 12% with D=24.5 nm. After annealing at 500^{\circ}C MLM of crystalline Sc_3Si_5/amorphous Si was formed instead of the original one. The periodic structure of MLMs deteriorated after annealing at 530^{\circ}C for one hour.

Journal: Journal of X-Ray Science and Technology, vol. 9, no. 1, pp. 35-42, 2001