TF7:
EUV and Soft X-Ray Multilayers
Posters
TF7.1.P
The structure of layers and interfaces in Co/C X-ray multilayers
Ye. Bugayev, V. Kondratenko, I. Kopylets, Ye. Zubaryev
National Technical University “Kharkov Polytechnic Institute”, Kharkov, Ukraine
The structural quality of layers and interfaces in Co/C X-ray multilayers with period
~2.3 nm deposited by magnetron sputtering onto different substrates (glass, silicon, fused
quartz) has been studied by means of transmission electron microscopy, electron diffraction
and small angle X-ray scattering (=0.154 and 0.166 nm). The structure of cobalt and
carbon layers in as-deposited state is amorphous. The smooth and continuous cobalt layers
are formed at thickness over 1 nm. The interlayer roughness development in dependence of
number of layers has been revealed by means of comparison of calculated and experimental
reflectivity curves.
The reflectivity of Co/C multilayers with different thickness ratio of cobalt and
carbon has been measured near the normal incidence (~80°) at CK line (=4.47 nm).
It has been shown that the interlayer roughness can be decreased by applying postannealing at 250-270 °C. The reflectivity increases by 15-20% at =4.47 nm.
TF7.2.P
GRAZING INCIDENCE SMALL ANGLE X-RAY SCATTERING
FROM W/Si MULTILAYER GRATINGS
M. Jergel1, P. Mikulík2, L. Ortega3, A. Mazuelas4, E. Majkova1, E. Pinčík1, Š. Luby1,
I. Kostič5, P. Hudek5
1
Institute of Physics, SAS, 842 28 Bratislava, Slovakia
2
Fraunhofer Institut für Zerstörungsfreie Prüfverfahren, EADQ, Krügerstr. 22,
D-01326 Dresden, Germany
3
Laboratoire de Cristallographie du CNRS, BP 166, F-38042 Grenoble, France
4
European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France
5
Institute of Informatics, SAS, 842 37 Bratislava, Slovakia
Multilayer gratings are thin film structures with periodicities in lateral and vertical
directions giving the sample some unique properties. The structural characterization is of
primary importance to control the dominant properties of interest. X-ray scattering methods
provide a non-destructive tool giving access to both the surface morphology and internal
structure of the grating at the same time. We have studied an optical lamellar amorphous
tungsten-silicon multilayer grating with nominal lateral and normal periods of 800 nm and
8 nm, respectively, prepared by electron beam evaporation and electron beam lithography.
Grazing-incidence small-angle X-ray scattering (GISAX), i.e. coplanar and non-coplanar
X-ray reflectivity (XRR), have been measured with laboratory rotating anode and
synchrotron (ESRF, Grenoble) sources, respectively.
The vertical layer set-up (layer thicknesses and their stacking) and the interface
roughnesses (including the damage of the topmost period) of the multilayer grating are
determined from the fit of coplanar measurements utilizing a point scintillation detector.
This coplanar measurement corresponds to conventional XRR measurement from
multilayers with the scattering plane perpendicular to wires. The calculations are performed
within the framework of dynamical theory of XRR from rough gratings.
The non-coplanar scattering images were recorded by a scan of a linear positionsensitive detector and by a two-dimensional area detector. The recorded GISAX features
under various sample azimuths with respect to the wire array are explained qualitatively
using constructions in the reciprocal space. Slight imperfections of the real grating structure
with respect to perfectly straight wires due to the preparation procedure (electron beam
stamping and etching) have been revealed and are subject of the analysis. The highest
sensitivity to wire side wall imperfections is supposed to happen with the incident beam
parallel to wires. However, the evanescent wave propagation in the lateral direction (the
lateral angle of incidence on side walls is below the critical angle) makes the theoretical
analysis difficult and thus it has to be further improved to become a quantitative method for
side wall quality testing.

Corresponding author : Petr Mikulík, Fraunhofer Institut für Zerstörungsfreie Prüfverfahren, EADQ,
Krügerstr. 22, D-01326 Dresden, Germany, e-mail: mikulik@physics.muni.cz, tel +49+351-26482,
fax +49+351-28217;
TF7.3.P
The structure of interfaces in as-deposited, annealed and irradiated Mo/Si
multilayers
E.N. Zubarev, V.V. Kondratenko, V.A. Sevryukova, A.V Pen’kov
National Technical University, Kharkov, Ukraine
The structure of interfaces in as-deposited, annealed and irradiated Mo/Si multilayers
prepared by dc-magnetron sputtering onto single-crystalline Si(111) wafers has been
studied by high resolution cross-section electron microcopy, large- and small-angle X-ray
scattering with computer simulation of small-angle X-ray spectra. The formation
mechanism of intermixed transition zones (ITZ) at the different interfaces in Mo/Si
multilayers has been suggested. According to this mechanism the ITZ formation on Mo-onSi interface is defined by surface diffusion of Si atoms into growing Mo-layer. At the same
time the ITZ formation on Si-on-Mo interface is provided by bulk diffusion of Si atoms
into formed Mo-layer. The symmetrical ITZs with thickness tMo-on-Si  tSi-on-Mo1.2 nm and
phase composition of MoSi2 are formed at the both interfaces when the structure of Molayer is amorphous ( 0.9 nm tMo2.3 nm). Mo-layer is fully consumed on silicide
formation when the nominal Mo-layer thickness is less than 0.9 nm. As a result, MoSi2/Si
multilayer is formed. When the nominal thickness of Mo-layer is more than tMo2.3 nm,
polycrystalline structure of Mo-layer with clear texture is observed. In this case, the Mo
atoms arriving onto molybdenum surface can penetrate into the perfect Mo grains only due
to the bulk diffusion mechanism. As a result, the thin ITZ with thickness
tSi-on-Mo0.6 nm is formed. An unexpected result is came out, when the thickness of Molayer exceeds more than 12 nm. The ITZ is not revealed on Si-on-Mo interface. The
multilayer is described by 3-layer model. An absence of the ITZ connected with generation
of compressive stress in the Mo-layer when its thickness is increasing. Compressive
stresses reduce equilibrium and nonequilibrium vacancy concentration in the growing Mo
film. When vacancy concentration in Mo-layer is very low , the ITZ on the Mo-on-Si is
not formed.
Annealing of Mo/Si multilayers at temperatures range above 350400 oC leads to grow
of MoSi2 silicide on the Mo-on-Si interface without visible changes of the Si-on-Mo one.
The MoSi 2 is amorphous when its summary thickness ( t MoSi 2 ) less than 3.0 nm and
crystalline when t MoSi 2  3.0 nm. The silicide growth is occurred on Mo-on-MoSi 2
interface by means of diffusion of Si-atoms from the Si-layer through the silicide.
Activation energies of this process are 2.03 eV and 2.36 eV for amorphous and crystalline
disilicide, respectively.
The period of Mo/Si multilayers is reduced and the thickness of the both ITZ is
increased during irradiation them by high energy He+ ions. The density of the ITZ in
irradiated multilayers is less than in as-deposited ones.