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
_3
Si
_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.
