Publications by Petr Mikulík
There is a list of selected publications by Petr Mikulík here:

Difrakce na kvaziperiodických supermřížkách
(diploma thesis, 1993)

La caracterisation du systeme epitaxial tungstene/saphir
par la diffusion des rayons X
(diploma thesis, 1993)

Xray diffraction on Fibonacci superlattices
(article, Acta Cryst. 1995)

Scattering on aperiodic superlattices
(article, in proceedings "Beyond Quasicrystals" 1995)

Epitaxial growth and characterization of Y_{2}Co_{17}(0001)
thin films deposited on W(110)
(article, J. Appl. Phys. 1995)

Multiple diffraction of particles on a system of point scatterers
as an exactly soluble problem using the Ewald concept
(article, J. Phys. (UK) 1996)

Theoretical description of multiple crystal arrangements
(article, in proceedings book 1996)

Dynamical theory of diffraction of particles: Ewald's approach
(article, Scripta fac. sci. nat. univ. masaryk. brun. 1996)

XRay Reflectivity from Planar and Structured Multilayers
(PhD thesis, 1997)

Xray reflection by multilayer surface gratings,
(article, Physica B 1998)

Highly regular selforganization of step bunches during growth of SiGe on
Si(113) (article, Appl. Phys. Lett. 1998)

Xray reflection by rough multilayer gratings.
Dynamical and kinematical scattering
(article, Phys. Rev. B 1999)

Structural characterization of a lamellar W/Si multilayer grating,
(article, J. Appl. Phys. 1999)

Structural characterization of lamellar multilayer gratings
by Xray reflectivity and scanning electron microscopy
(article, J. Phys. D 1999)

Strain relaxation in periodic arrays of Si/SiGe quantum wires
determined by coplanar high resolution xray diffraction and grazing
incidence diffraction
(article, J. Phys. D 1999)

Highresolution xray diffraction on selforganized step bunches of
Si_{1x}Ge_{x} grown on (113)oriented Si
(article, J. Phys. D 1999)

Xray reflectivity by rough multilayers
(review article, proceedings book XRay and Neutron Reflectivity:
Principles and Applications, Springer 1999)

Xray diffraction from quantum wires and quantum dots
(article, J. Mater. Sci.: Mat. in Electr. 1999)

The crystal truncation rod scattering of neutrons and the multiwave
dynamical theory of diffraction
(article, J.Phys.: Condens. Matter 1999)

Selfassembled carboninduced germanium quantum dots studied by
grazingincidence smallangle xray scattering
(article, Appl. Phys. Lett. 1999)

Multilayer gratings for XUV optics
(article, acta physica slovaca 2000)

Nearly perfect 3D ordering in IVVI quantum dot superlattices with
ABCABC... vertical stacking sequence
(article, Physica E 2000)

Coplanar and noncoplanar xray reflectivity characterization of
lateral W/Si multilayer gratings,
(article, J. Phys. D 2001)

Xray diffraction and reflectivity analysis of GaAs/InGaAs
freestanding trapezoidal quantum wires,
(article, J. Phys. D 2001)

Coplanar and noncoplanar xray reflectivity characterization
of lateral W/Si multilayer gratings
(article, Sup. y Vac. 2001)

Strain in buried quantum wires: Analytical calculations and xray
diffraction study
(article, Phys. Rev. B 2002)

Advanced Xray diffraction imaging techniques for semiconductor wafer
characterisation
(article, Materials Structure 2002)

Synchrotron area diffractometry as a tool for spatial highresolution
threedimensional lattice misorientation mapping
(article, J. Phys. D: Appl. Phys. 2003)

Twodimensional xray magnification based on a monolithic beam conditioner
(article, J. Phys. D: Appl. Phys. 2003)

Determination of lattice plane curvature and dislocation Burgers vector density
in crystals by rocking curve imaging technique
(article, Proceedings SPIE Volume 5195 2003)

Micro and nanoNDE in the laboratory for acoustic diagnosis and quality assurance
(article, Proceedings SPIE Volume 5392 2004)

Synchrotronradiation Xray tomography: a method for 3D imaging of cement
microstructure and its evolution during hydration
(article, Proceedings SANACE 2004)

Distribution and Burgers vectors of dislocations in semiconductor wafers investigated by rockingcurve imaging
(article, J. Appl. Cryst. 2005)

Local wing tilt analysis of laterally overgrown GaN by xray rocking curve imaging
(article, J. Phys. D 2005)

Monolithic twodimensional beam compressor for hard xray beams
(article, J. Phys. D 2005)

Highresolution threedimensional imaging of flat objects by synchrotronradiation
computed laminography
(article, Appl. Phys. Lett. 2005)

Threedimensional imaging of cement microstructure evolution during hydration
(article, Advances in Cement Research 2005)

Spontaneous lateral modulation in shortperiod superlattices investigated
by grazingincidence xray diffraction
(article, Physical Review B 2005)

Aberrations of diffractive–refractive optics: Braggcase sagittal focusing
of multiple parabolic elements
(article, J. Phys. D 2005)

Xray microdiffraction imaging investigations of wing tilt in epitaxially
overgrown GaN
(article, physica status solidi (a) 2006)

Investigation of hybrid pixel detector arrays by synchrotronradiation
imaging
(article, Nuclear instruments & methods in physics research A 2006).

Crystallite misorientation analysis in semiconductor wafers and ELO samples
by rocking curve imaging
(article, Applied Surface Science 2006)

Synchrotronradiation computed laminography for highresolution threedimensional
imaging of flat devices
(article, physica status solidi (a) 2007).

Development of oxide precipitates in silicon: calculation of the distribution
function of the classical theory of nucleation by a nodalpoints approximation
(article, J. Phys.: Condens. Matter 2007)

On the design of a monolithic 4bounce high resolution Xray monochromator
(article, Nuclear Instruments and Methods in Physics Research B 2007).

Diffuse xray scattering from statistically inhomogeneous distributions
of threading dislocations beyond the ergodic hypothesis
(article, Physics Review B 2008)

High Resolution 1D and 2D Crystal Optics Based on Asymmetric Diffractors
(chapter, book
Modern Developments in XRay and Neutron Optics, Springer 2008)

Thermal effects under synchrotron radiation power absorption
(chapter, book
Modern Developments in XRay and Neutron Optics, Springer 2008)

Microdiffraction imaging of dislocation densities in microstructured samples
(article, Europhysics Letters 2008)

ÚFKL PřF MU: polovodiče, nanostruktury, čisté prostory
(article, Československý časopis pro fyziku 2008)

Design and Fabrication of HighTemperature SOI StrainGauges
(article, in proceedings 2008)

Projekt Středoevropské synchrotronové laboratoře – CESLAB
(article, Československý časopis pro fyziku 2008)

Correctness of a particular solution of inverse problem in rocking curve imaging
(article, Physica Status Solidi A 2009)

Xray reflectivity by rough multilayers
(chapter in book XRay and Neutron Reflectivity:
Principles and Applications, Springer 2009)

Optical Characterization of UltraThin Iron and Iron Oxide Films
(article, eJournal of Surface Science and Nanotechnology 2009)

Diffractiverefractive optics: lowaberration Braggcase focusing by precise parabolic surfaces
(article, Journal of Synchrotron Radiation 2010)

Linearly graded GeSi beamexpanding/compressing Xray monochromator
(article, Journal of Applied Crystallography 2010)

Profiling NType Dopants in Silicon
(article, Materials Transactions 2010)

Plasma polymer films of tetravinylsilane modified by UV irradiation,
(article, Surface and Coatings Technology 2010)

Highly asymmetric Laue focusing monochromator
(article, AIP Conference Proceedings 2010)

1D Xray Beam Compressing Monochromators
(article, AIP Conference Proceedings 2010)

Diffractiverefractive optics: (+,,,+) Xray crystal monochromator
with harmonics separation
(article, Journal of Synchrotron Radiation 2011)

Xray diffracted intensity for doublereflection channelcut Ge
monochromators at extremely asymmetric diffraction conditions
(article, Journal of Applied Crystallography 2011)

Xray collimation by crystals with precise parabolic holes based on
diffractiverefractive optics
(article, Journal of Synchrotron Radiation 2011)

On the implementation of computed laminography using synchrotron radiation
(article, Review of Scientific Instruments 2011)

Inline Bragg magnifier based on Vshaped germanium crystals
(article, Journal of Synchrotron Radiation 2011)

A proofofprinciple experiment of a novel harmonics separation optics
for synchrotron facilities
(article, Journal of Synchrotron Radiation 2012)

Processing of projections containing phase contrast in laboratory microcomputerized tomography imaging
(article, Journal of Applied Crystallography 2013)

Potential use of V‐channel Ge(220) monochromators in X‐ray metrology and imaging
(article, Journal of Applied Crystallography 2013)

Processinduced inhomogeneities in higher asymmetry angle Xray monochromators
(article, Proceedings SPIE Volume 8848 2013)

Simulations and surface quality testing of high asymmetry angle Xray
crystal monochromators for advanced Xay imaging applications
(article, Proceedings SPIE Volume 9207 2014)

The benefit of the European User Community from transnational access to national radiation facilities
(article, Journal of Synchrotron Radiation 2014)

Calculations and surface quality measurements of highasymmetry angle xray crystal monochromators
for advanced xray imaging and metrological applications
(article, Optical Engineering 2015)

Local strain and defects in silicon wafers due to nanoindentation revealed by fullfield Xray microdiffraction imaging
(article, Journal of Synchrotron Radiation 2015)

Towards highflux Xray beam compressing channelcut monochromators
(article, Journal of Applied Crystallography 2016)
P. Mikulík:
Difrakce na kvaziperiodickych supermrizkach
(Diffraction On Quasiperiodic Superlattices),
Diploma Thesis, Masaryk University, Brno, 1993 (in Czech).
P. Mikulík:
La caracterisation du systeme epitaxial tungstene/saphir par la diffusion des rayons X
and Structural Characterization Of The Epitaxial Layered System Tungsten/Sapphire By XRay Scattering,
Diploma Thesis/DEA report, Université Joseph Fourier, Grenoble, 1993
(two equivalent versions: in French and in English).
P. Mikulík, V. Holý, J. Kubena, and K. Ploog,
Xray diffraction on Fibonacci superlattices,
Acta Cryst.
A 51, 825–830 (1995).
Abstract
The exact diffraction curve of the Fibonacci superlattice is calculated
using the semikinematical approximation of dynamical Xray diffraction.
The properties of the discrete Fourier transform of quasiperiodically
arranged layers are employed to get explicit approximate formula for
the diffracted intensity and for the angular positions of peaks.
The exact and approximate curves were compared
by a numerical simulation and a good agreement was found.
The measurement of diffraction curve was performed
on the generalized Fibonacci superlattice
built by stacked Fibonacci generations. This superlattice belongs to the
same class of local isomorphism as the Fibonacci superlattice if both are
infinitely thick.
The explicit approximate formulae enabled to fit the structural
parameters of the superlattice even in the low resolution experimental setup
when the fit of the whole measured diffraction curve
was not possible.
P. Mikulík, Scattering on aperiodic superlattices,
in
Beyond Quasicrystals
(lecture 9, p. 229), ed. by F. Axel and D. Gratias,
Les Editions de Physique, 1995.
Abstract
[well, this is not an abstract, but one paragraph from the Introduction]
The paper is organized as follows. In the second part
the Xray diffraction theories for studying SLs will be presented.
In the third part both the kinematical theory
and the semikinematical approximation of dynamical theory
will be used to calculate both the positions and the intensities of
the diffraction peaks
of the Fibonacci SL by the Fourier transform treatment and by an exact
treatment. The diffraction curve of Fibonacci SL will be compared with
that of a periodic SL. Diffraction patterns
of other types of aperiodic superlattices will be reviewed briefly.
The fourth part concerning Xray reflectivity will demonstrate
the equivalence between the reflectivity and diffraction.
In the last section the idea of a Fibonacci grating
will be proposed and the reciprocal space intensity distribution
will be kinematically calculated.
Note: either buy the whole book, or mail me and I give you the cameraready
postscript file of my article.
F. Robaut, P. Mikulík, N. Cherief, O.F.K. Mc Grath, D. Givord,
T. Baumbach, and J.Y. Veuillen,
Epitaxial growth and characterization of Y_{2}Co_{17}(0001)
thin films deposited on W(110),
J. Appl. Phys. 78, 997–1003 (1995).
V. Holý and P. Mikulík,
Theoretical description of multiple crystal arrangements.
Pages 259–268.
In Proceedings of the 23rd course of the International School of
Crystallography: "Xray and neutron dynamical diffraction: theory and
applications".
Plenum Press, 1996.
O. Litzman, P. Mikulík, and P. Dub,
Multiple diffraction of particles on a system of
point scatterers as an exactly soluble problem using the Ewald concept,
J. Phys. (UK) 8, 4709–4725 (1996).
Abstract
Reflection of a de Broglie plane wave incident on a system if point scatterers
(nuclei) forming an ideal semiinfinite crystal is studied using the Tmatrix
formalism of Ewald's dynamical theory of diffraction. Using from the beginning
the twodimensional translational symmetry of the crystal bordered by a surface,
simple exact manybeam analytical formulae for the intensities of the reflected
waves are deduced, whereby the Ewald sphere is replaced by "the gammadiagrams"
and the usual threedimensional dispersion surface by twodimensional "dispersion
plot". The results obtained are valid for arbitrary angles of incidence
(including the grazing incidence, Bragg angle near pi/2, near or far from the
Bragg reflection position) and for any directions of the reflected waves
(including both the coplanar and noncoplanar reflections). The transparent
algebraic form of the final formulae allows us to discuss analytically the
solutions of the dispersion relation and the intensities of the reflections in
two and manybeam approximations.
P. Dub, O. Litzman, and P. Mikulík,
Dynamical theory of diffraction of particles: Ewald's approach,
Scripta fac. sci. nat. univ. masaryk. brun. 26, 5–38 (1996).
Abstract
Using Ewald's selfconsistent theory of multiple scattering the
reflection of the scalar plane wave on an ideal semiinfinite
crystal formed by pointlike diffraction centres is studied.
Exact manybeam dispersion relation and analytical formulae for
the reflectivity deduced in our previous papers are analyzed and
brought into new forms apt for application in the shortwavelength
region. The obtained expression for the reflectivity is effective
for the socalled crystal truncation rod scattering as well as
the usual Bragg reflection, including the special cases such as total
reflection at grazing incidence, Bragg reflection at the Bragg
angle Pi/2, and for both coplanar and noncoplanar reflections.
P. Mikulík:
Xray Reflectivity From Planar And Structured Multilayers,
PhD. thesis.
Université Joseph Fourier (Grenoble)
and Masaryk University (Brno), 1997.
Abstract
The Xray reflection from planar and structured multilayers is presented using
different theoretical approaches. The scattering phenomena studied are the
specular reflection from planar multilayers with various stacking sequences
(single layer, periodic, quasiperiodic), the diffuse scattering from rough
multilayers, and the scattering from surface gratings and from multilayer
gratings. The theories employed for the calculation are: the kinematical theory,
the distortedwave Born approximation, the dynamical theory and various
approximations of the dynamical theory (the singlereflection approximation, the
twobeam approximation and the multiplebeam approximation), developed in one
unified formalism. This unified formalism enables all these theories to be
discussed and compared in a consistent and methodological way. Numerical
calculations are applied to fit the experimental curves in order to reveal the
structural parameters of miscellaneous types of layered samples.
You may visit the Web page devoted entirely
to my PhD thesis.
P. Mikulík and T. Baumbach
Xray reflection by multilayer surface gratings,
Physica B 248, 381–386 (1998).
Abstract
Xray reflection by multilayer gratings has been investigated theoretically and
experimentally. A theoretical treatment based on the DWBA method has been
developed and compared with the full dynamical and the kinematical approaches.
All three theories are treated in one uniform formalism, taking away the usual
restrictions of the Fraunhofer approximation in order to simplify the direct
numerical comparison. Contrary to the wide spread opinion the DWBA shows good
agreement especially for the intense grating truncation rods. The regions of
validity of the DWBA are proved by exact dynamical calculations. The dynamical
diffraction by the multilayered grating has been formulated by a matrix formalism
generalizing the Fresnel transmission and reflection coefficients for diffraction,
which describe the interaction of the scattering by different grating truncation
rods. The concept of Ewald's sphere allows a transparent interpretation of the
different scattering phenomena and the influence of Umweganregung on the
scattering pattern. The theories are applied on first experimental results of
epitaxial multilayer gratings.
Note: poster presented at the International Conference on
Fifth International Conference on Xray and Neutron Surface Scattering,
Oxford, July 1997.
A.A. Darhuber, J. Zhu, V. Holý, J. Stangl,
P. Mikulík, K. Brunner, G. Abstreiter, and G. Bauer,
Highly regular selforganization of step bunches during growth of SiGe on Si(113),
Appl. Phys. Lett. 73, 1535–1537 (1998).
P. Mikulík and T. Baumbach,
Xray reflection by rough multilayer gratings.
Dynamical and kinematical scattering.
Phys. Rev. B 59, 7632–7643 (1999).
Abstract
Xray reflectivity by rough multilayer gratings is treated in the framework of the
kinematical and dynamical theories. The kinematical scattering integral is
calculated without the restrictions of the Fraunhofer approximation. The
dynamical theory is presented by the matrix modal eigenvalue approach. In both
theories we generalize the Fresnel reflection and transmission coefficients for
the case of grating diffraction. We obtained one unique formalism which permits
us to compare directly the results of both theories. Furthermore, interface and
side wall roughnesses are taken into account. The dynamical approach allowed to
explain the experimental results obtained from a partially etched GaAs/InP
periodic multilayer grating.
M. Jergel, P. Mikulík, E. Majková, Š. Luby, R. Senderák, E. Pinčík, M. Brunel,
P. Hudek, I. Kostič, and A. Konečníková,
Structural characterization of a lamellar W/Si multilayer grating,
J. Appl. Phys. 85, 1225–1227 (1999).
Abstract
A lamellar multilayer grating of the nominal normal and lateral periods
8 nm and 800 nm, respectively, was obtained by etching a planar
amorphous W/Si multilayer up to the substrate. The specular reflectivity,
grating truncation rods of nonzero orders, and a reciprocal space map of the
scattered intensity close to the total external reflection were measured using
the CuKa radiation. For the first time, we demonstrate an extraction of real
structural parameters of a fully etched periodic multilayer grating from fitting
the measured truncation rods based on the matrix modal eigenvalue approach to
the dynamical theory of reflectivity by gratings.
M. Jergel, P. Mikulík, E. Majková, Š. Luby, R. Senderák, E. Pinčík, M. Brunel,
P. Hudek, I. Kostič, and A. Konečníková,
Structural characterization of lamellar multilayer gratings
by Xray reflectivity and scanning electron microscopy,
J. Phys. D 32, A220–A223 (1999).
Abstract
Structural characterisation of a fully etched amorphous W/Si multilayer grating
with lateral periodicity 800 nm is performed by Xray reflectivity.
Grating truncation rod profiles have been calculated using a matrix modal
eigenvalue approach of the dynamical theory of reflectivity by gratings which
generalizes the Fresnel transmission and reflection coefficients for lateral
diffraction. The interface roughness in rough gratings has been taken into
account by a coherent amplitude approach which damps the generalized Fresnel
coefficients. Scanning electron microscopy pictures complete the study.
Y. Zhuang, V. Holý, J. Stangl, A.A. Darhuber, P. Mikulík, S. Zerlauth,
F. Schäffler, G. Bauer, N. Darowski, and D. Lübbert,
Strain relaxation in periodic arrays of Si/SiGe quantum wires
determined by coplanar high resolution xray diffraction and grazing
incidence diffraction,
J. Phys. D 32, A224–A229 (1999).
Abstract
Elastic relaxation in dryetched periodic wires fabricated from molecular beam
epitaxy grown Si/SiGe multilayers was studied by coplanar and grazing incidence
(GID) highresolution xray diffraction. The inhomogeneous strain distribution
in the wires was calculated by the finite element method, which provided the
input data for simulations of the scattered intensities using kinematical
diffraction theory used for comparison with measured reciprocal space maps. A
fabricationinduced layer covering the wire surfaces, modifies the strain
distribution. Using GID, the geometrical shape of the wires and their inplane
strain can be determined independently of each other.
J. Stangl, V. Holý, A.A. Darhuber, P. Mikulík, G. Bauer, J. Zhu, K. Brunner, G. Abstreiter,
Highresolution xray diffraction on selforganized step bunches of
Si_{1x}Ge_{x} grown on (113)oriented Si,
J. Phys. D 32, A71–A74 (1999).
Abstract
We present investigations of a highly regular terraced surface and interface
structure of Si/SiGe multilayers on Si(113) by xray diffraction, xray
reflectivity and atomic force microscopy. A regular array of step bunches with
lateral periods of several hundred nanometres is formed during the growth of the
Si/Si_{1x}Ge_{x} multilayers. Xray diffraction patterns are
simulated using the elastic Green function approach for the evaluation of the
strain fields associated with the step edges, taking into account the relaxation
towards the free surface. In addition to the terrace structure, a surface
waviness on the micrometer length scale is present, leading to a modulation of
the terrace widths.
T. Baumbach and P. Mikulík,
Xray reflectivity by rough multilayers
(review article, pages 155–161 and 232–280).
Proceedings of the Ecole Française de Reflectivité
(Luminy, France, 1997): XRay and Neutron Reflectivity: Principles
and Applications, edited by J. Daillant and A. Gibaud,
Berlin: Springer, Lecture Notes in Physics: 58 (1999).
Online here:
chapter 4.
and
chapter 8.
Excerpt from the table of contents:
4.A Appendix contributed by T. Baumbach and P. Mikulík.
Incoherent approach for scattering by randomly disturbed
multilayers ................................................. 3
4.A.1 Formal theory ......................................... 3
4.A.2 Formal kinematical treatment by first order Born ap
proximation ............................................ 5
4.A.3 Formal treatment by a distorted wave Born approximation 6
imation ...........................................
8 Xray reflectivity by rough multilayers
by Tilo Baumbach and Petr Mikulík 11
8.1 Introduction ................................................. 12
8.2 Description of rough multilayers ............................. 13
8.2.1 Ideal planar multilayers ............................... 14
8.2.2 Multilayers with rough interfaces ...................... 15
8.2.3 Correlation properties of different interfaces ......... 15
8.3 Setup of Xray reflectivity experiments ...................... 17
8.3.1 Experimental setup ..................................... 17
8.3.2 Experimental scans ..................................... 19
8.4 Specular Xray reflection .................................... 21
8.4.1 Roughness with a Gaussian interface distribution
function .............................................. 21
8.4.2 Stepped surfaces ....................................... 28
8.4.3 Reflection by "virtual interfaces" between porous layers 30
8.5 Nonspecular Xray reflection ................................ 31
8.5.1 Interfaces with a Gaussian roughness profile ........... 31
8.5.2 The main scattering features of nonspecular reflection
by rough multilayers ................................... 35
8.5.3 Stepped surface and interfaces ......................... 40
8.5.4 Noncoplanar NSXR ...................................... 43
8.6 Interface roughness in surface sensitive diffraction methods . 44
8.7 Xray reflection from multilayer gratings .................... 47
8.7.1 Theoretical treatments ................................. 48
8.7.2 Discussion ............................................. 53
8.7.3 Reflectivity from rough multilayer gratings ............ 54
8.A Appendix. Reciprocal space constructions for reflectivity .... 57
8.A.1 Reflection from planar surface and interfaces .......... 57
8.A.2 Periodic multilayer .................................... 59
8.A.3 Reciprocal space representation of DWBA ................ 60
Bibliography ..................................................... 62
Y. Zhuang, J. Stangl, A.A. Darhuber, G. Bauer, P. Mikulík, V. Holý, N. Darowski,
and U. Pietsch,
Xray diffraction from quantum wires and quantum dots,
Journal of Materials Science: Materials in Electronics 10, 215–221
(1999).
Abstract
From the distribution of the scattered intensity in reciprocal space,
information on the shape as well as on the strain distribution in
nanostructured samples can be obtained. This is exemplified by applying this
method to laterally patterned periodic Si/SiGe superlattices as well as to
periodic SiGe dot arrays embedded in Si.
O. Litzman and P. Mikulík,
The crystal truncation rod scattering of neutrons and the multiwave
dynamical theory of diffraction,
J.Phys.: Condens. Matter 11, 5767 (1999).
Abstract
The influence of the Bragg diffractions on the coplanar and noncoplanar
crystal truncation rod scattering is studied using the Ewald multiwave
dynamical theory of diffraction. The resulting formulae are compared with the
approximate ones of the kinematical theory and geometrical optics
approximations.
J. Stangl, V. Holý, P. Mikulík, G. Bauer, I. Kegel, T.H. Metzger, O.G. Schmidt,
C. Lange, and K. Eberl,
Selfassembled carboninduced germanium quantum dots studied by
grazingincidence smallangle xray scattering,
Applied Physics Letters 74, 3785–3787 (1999).
Abstract
We present a structural investigation of buried Cinduced Ge quantum dot
multilayers grown on (001) Si by molecularbeam epitaxy. Using grazingincidence
smallangle xray scattering, we determine the shape, the mean radius, height,
and dot distance. The dot distribution is isotropic within the (001) interfaces,
and no correlation of the dot positions along growth direction was found.
M. Jergel, P. Mikulík, E. Majková, E. Pinčík, Š. Luby, M. Brunel, P. Hudek,
I. Kostič,
Multilayer gratings for XUV optics,
acta physica slovaca 50, 427–438 (2000).
Abstract
Multilayer gratings are thin film structures possessing periodicities both in
the normal and lateral directions. They combine the properties of surface
gratings and planar multilayers thus providing a high throughput and high
spectral resolution on higher diffraction orders. The unique diffraction
properties are utilized in the Xray and ultraviolet optics where no lenses or
mirrors comparable with those for visible light are available. Multilayer
gratings act as constant resolution dispersion elements in a broad spectral
range. A fan of grating diffractions in real space is represented by a set of
points on equidistant truncation rods in the reciprocal space. The kinematical
theory of Xray scattering explains well the positions of the grating truncation
rods while the dynamical theory is inevitable to calculate the intensities along
the truncation rods (grating efficiency). The properties of multilayer gratings
are exemplified on two differently prepared lamellar gratings with the nominal
normal and lateral periods of 8 nm and 800 nm, respectively. The fabrication
steps are described in detail. The specular and nonspecular Xray
reflectivities at wavelength 0.15418 nm were measured on one of the samples.
The dynamical theory of Xray scattering with a matrix modal eigenvalue
approach was applied to extract the real structural parameters such as the
surface and interface roughnesses, individual layer thicknesses, and the lamella
width to the grating period ratio. The Xray reflectometry is completed by
microscopy observations which provide complementary and direct information on
the local surface profile.
G. Springholz, J. Stangl, M. Pinczolits, V. Holý, P. Mikulík, P. Mayer,
K. Wiesauer, G. Bauer, D. Smilgies, H.H. Kang, and L. SalamancaRiba,
Nearly perfect 3D ordering in IVVI quantum dot superlattices with
ABCABC... vertical stacking sequence,
Physica E 7, 870–875 (2000).
Abstract
Selforganization of PbSe islands in epitaxial PbSe/Pb1xEuxTe superlattices is shown to result in
a spontaneous threedimensional ordering of the PbSe dots in a trigonal lattice with a feelike
ABCABC vertical stacking sequence. From Xray diffraction reciprocal space maps, the
interlayer correlation direction of the PbSe dots is found to be inclined by 40 degrees with
respect to the [111] surface normal. Peak profile measurements in the reciprocal space maps
yield a coherence length of the ordered regions of 300 +/ 100 nm in the lateral, and of 530 +/
50 nm in the vertical direction. This corresponds to ordered regions that contain as many as 250
PbSe dots.
P. Mikulík, M. Jergel, T. Baumbach, E. Majková, E. Pinčík, Š. Luby,
L. Ortega, R. Tucoulou, P. Hudek, and I. Kostič,
Coplanar and noncoplanar xray reflectivity characterization of
lateral W/Si multilayer gratings,
J. Phys. D: Appl. Phys. 34, A188–A192 (2001).
Abstract
Structural characterization of a fully etched amorphous W/Si multilayer grating
with a lateral periodicity of 800 nm is performed by xray reflectivity in the
coplanar and noncoplanar modes using a scintillation detector and a
twodimensional gasfilled detector, respectively. Threedimensional reciprocal
space constructions were used to explain the scattering features recorded in
both geometries. Coplanar coherent grating truncation rods were fitted by a
dynamical theory for rough gratings. Comparison of the reflectivity from the
reference planar multilayer completes the study.
A. Ulyanenkov, K. Inaba, P. Mikulík, N. Darowski, K. Omote, U. Pietsch,
J. Grenzer, and A. Forchel,
Xray diffraction and reflectivity analysis of GaAs/InGaAs
freestanding trapezoidal quantum wires,
J. Phys. D: Appl. Phys. 34, A179–A182 (2001).
Abstract
Combined xray diffraction and reflectivity experiments have been performed on
freestanding trapezoidal GaAs/InGaAs quantum wires using a conventional xray
tube. Interpreting the intensity distribution around (004) by curve simulation
of the extracted coherent grating truncation rods on the basis of a
semikinematical diffraction theory (DWBA) the shape and geometric parameters as
well as the strain within the wires could be determined taking the results of a
finite element calculation of the atomic displacements into account. The map of
the coplanar xray reflectivity around (000), as well as the intensity profiles
of the coherent grating truncation rods, located equidistantly around the
specularly reflected beam, have been recorded in order to estimate the
roughness properties of the sample interfaces as well as the wire shape and
layer setup without the influence of strain. All smallangle as well as
wideangle scattering experimental results went in to the mutually consistent
estimate of the sample properties. The experiments performed for a conventional
xray tube supply a parameter set comparable in completeness and precision to
that obtained from similar samples by interpreting synchrotron experiments.
M. Jergel, C. Falcony, P. Mikulík, L. Ortega, E. Majková, E. Pinčík, Š. Luby,
I. Kostič, and P. Hudek,
Coplanar and noncoplanar xray reflectivity characterization
of lateral W/Si multilayer gratings,
Sup. y Vac. 13, 10 (2001).
Abstract
Multilayer gratings a re artificially patterned multilyer thin films with the
periodicities both in the lateral and normal directions which renders them
attracting for microelectronic and optical applications. A proper structural
characterization is of primary importance. To test the capability of the Xray
reflectometry technique to fulfil this task, a tungsten/silicon multilayer
grating prepared by electron beam evaporation and electron beam lithography was
studied both in the coplanar and noncoplanar geometries., the nominal lateral
and normal periods being 800 nm and 8 nm, respectively. The coplanar
measurements were evaluated within the dynamical theory of Xray scattering on
rough gratings and provided the structural parameters of a real structure with
a reasonable precision which are close to the nominal ones. The results
revealed also some imperfections of the deposition and masking procedures which
are discussed. The noncoplanar measurements were evaluated qualitatively using
threedimensional constructions in the reciprocal space. The advantage of the
technique used is its nondestructive character and a simultaneous access both
to the surface shape of the grating as well as to its internal structure.
V.M. Kaganer, B. Jenichen, G. Paris, K.H. Ploog, O. Konovalov, P. Mikulík,
and S. Arai,
Strain in buried quantum wires: Analytical calculations and xray
diffraction study,
Phys. Rev. B 66, 0353101–0353107 (2002).
Abstract
The displacement field in and around periodically arranged quantum wires
embedded in a crystalline matrix is calculated analytically for an arbitrary
finite thickness of the cover layer. A good agreement is obtained between
measured xraydiffraction peaks of a wire structure and kinematical
calculations with the displacement field derived in the paper. The strain and
quantum size effects on the photoluminescence line shift are found to be
comparable, due to small width (35 nm) of the wires.
P. Mikulík, T. Baumbach, D. Korytár, P. Pernot, D. Lübbert, L. Helfen,
Ch. Landesberger,
Advanced Xray diffraction imaging techniques for semiconductor wafer
characterisation,
Materials Structure 9, 87–88 (2002).
Abstract
Wafer quality inspection and defect analysis are crucial for improvements of
the wafer fabrication technology as well as for the correlation of device
properties with the processes of wafer treating. This work demonstrates trends
of highresolution Xray diffraction imaging techniques with synchrotron
radiation sources and their capability for detailed quality inspection of
wafers concerning their structural perfection. We apply these methods to
visualise and to characterise the defects and deformations induced by growing,
cutting, grinding, etching and gluing in the production of semiconductor wafers
(in particular Si and GaAs wafers) and in ultrathin wafers. We present
synchrotron topography and synchrotron area diffractometry methods to analyse
qualitatively and quantitatively: dislocations and lineages, microdefects and
microcracks, wafer tilts and warpages, tensors of local lattice rotations.
P. Mikulík, D. Lübbert, D. Korytár, P. Pernot, and T. Baumbach,
Synchrotron area diffractometry as a tool for spatial highresolution
threedimensional lattice misorientation mapping,
J. Phys. D: Appl. Phys. 36, A74–A78 (2003).
Abstract
We have developed a highresolution diffraction imaging method for
determination of the complete threedimensional rotational local lattice
misorientation of crystalline samples. The method, called synchrotron area
diffractometry, is based on recording doublecrystal diffraction rocking scans
in three mutually noncoplanar scattering planes with a twodimensional area
detector. The subsequent multiplepeak analysis of the rocking curve image
series for all pixels and their backprojection to the wafer surface provides
local misorientation angles (Euler angles) with spatial resolution up to
micrometre range over the wafer surface. We applied this technique to determine
the distribution of tilt and twist angles of the lattice misorientation of a
macroscopic defect localized in a 6 inch semiinsulating GaAs(001) wafer.
D. Korytár, P. Mikulík, C. Ferrari, J. Hrdý, T. Baumbach, A. Freund, and
A. Kuběna,
Twodimensional xray magnification based on a monolithic beam conditioner,
J. Phys. D: Appl. Phys. 36, A65–A68 (2003).
Abstract
In xray imaging and beam conditioning it is useful to magnify or demagnify the
xray beam, or an image, approaching (sub)micrometre resolution or the
(sub)micrometre illuminated region. Using an asymmetric diffractor it is
possible to expand or compress the xray beam in one direction. Combining two
such diffractors with mutually perpendicular planes of diffraction even
twodimensional beam expansion or compression can be obtained and, for suitable
wavelengths, it is even possible to design and cut a single crystal in such a
way that it works as a monolithic device expanding or compressing the xray
beam in two directions. In this paper, a new magnifying monolithic optical
device for a twodimensional magnification of 25 at 10 keV, based on two
noncoplanar asymmetrically inclined {311} diffractors, was designed and made
from a single silicon crystal. A raytracing image has been simulated to check
the functionality of the device. The experimental testing of this device was
performed at Optics beamline BM5 at ESRF Grenoble. An undistorted image
magnification of about 15 was achieved at a photon beam energy of 9.6 keV. When
the photon energy was increased, a higher magnification and increased
distortion were observed (horizontal magnification of 39, vertical
magnification of 20) at an energy of 10.045 keV. The advantages and
disadvantages of the device, as well as further steps to improve it are briefly
discussed.
C. Ferrari, N. Verdi, D. Lübbert, D. Korytár, P. Mikulík, T. Baumbach,
L. Helfen, and P. Pernot,
Determination of lattice plane curvature and dislocation Burgers vector density
in crystals by rocking curve imaging technique,
Proceedings SPIE Volume 5195: Crystals, Multilayers, and Other Synchrotron Optics,
edited by T. Ishikawa, A.T. Macrander, and J.L. Wood,
84–93 (2003).
Abstract
In the present work the lattice plane curvature of a nearly dislocation free
S:doped InP and a semiinsulating GaAs wafer crystals has been investigated
using the method of Xray rocking curve imaging based on the FReLoN CCD area
detector with a pixel resolution from 10 to 40 μm at the ID19 ESRF
beamline. The geometry of the experiment is based on a vertical Si (111)
monochromator and a horizontal sample scattering planes in the Bragg geometry
(σπ geometry). To determine the local lattice inclination, the effect
of such dispersive setup on the measured local diffraction peak position has
been accurately determined and the equations to determine the lattice plane
curvature of the crystals under the condition of isotropic distribution of
dislocation Burgers vectors are obtained. The analysis of the data showed that
the shift of the Bragg condition is almost completely due to the lattice tilt
rather than to the lattice parameter variation. Lattice displacements from the
ideal lattice as large as 200 μm are found at the edges of the InP
crystal. Non random distributions of dislocation Burgers vectors are observed
in both samples.
B. Köhler, J. Schreiber, B. Bendjus, M. Herms, V. Melov, L. Helfen, P. Mikulík,
and T. Baumbach,
Micro and nanoNDE in the laboratory for acoustic diagnosis and quality assurance,
Proceedings SPIE Volume 5392: Testing, Reliability, and Application of Micro and
NanoMaterial Systems II, edited by N. Meyendorf, G.Y. Baaklini, and B. Michel,
63–77 (2004).
Abstract
NDE activities at the Laboratory for Acoustic Diagnosis and Quality Assurance
(EADQ) Dresden are outlined. The applied methods comprise acoustic, thermal,
optical and Xray ones. Additionally, scanning probe methods (SPM) and scanning
electron microscopy (SEM) are used. Combinations of different methods are
especially effective. This is demonstrated for the coupling of an acoustic
approach with SEM. For NDE on a micro and nanometer scale, preparation of
appropriate test flaws and the verification of the NDE results turn out to be a
challenge. To meet this challenge, we propose an approach based on focused ion
beam technique.
T. Baumbach, L. Helfen, P. Mikulík, and F. Dehn
and T. Baumbach,
Synchrotronradiation Xray tomography: a method for 3D imaging of cement
microstructure and its evolution during hydration
,
Proceedings of XIV. International Symposium SANACE 2004, 71–80 (2004).
Abstract
New possibilities opened up by synchrotron radiation present xray tomography
as an experimental imaging method to study the microstructural evolution during
cement hydration. The present work demonstrates the potential of
synchrotronradiation microtomography for the investigation of cement structure
after solidification. Quantitative determination of the spatial absorption
coefficient distribution due to the use of monochromatic radiation and the
achieved high spatial resolution allows us to characterise the hydration
process of cement volume on a micrometre scale in three dimensions. In
particular, effects as the formation of microcracks and pores related to
autogeneous shrinkage involved with the hydration process could be observed for
the first time with down to one micrometre resolution.
D. Lübbert, C. Ferrari, P. Mikulík, P. Pernot, L. Helfen, N. Verdi, D. Korytár,
and T. Baumbach,
Distribution and Burgers vectors of dislocations in semiconductor wafers investigated
by rockingcurve imaging,
Journal of Applied Crystallography 38, 91–96 (2005).
Abstract
The method called rockingcurve imaging (RCI) has recently been developed to
visualize lattice imperfections in large crystals such as semiconductor wafers
with high spatial resolution. The method is based on a combination of Xray
rockingcurve analysis and digital Xray diffraction topography. In this
article, an extension of the method is proposed by which dislocation densities
in largescale samples (semiconductor wafer crystals) can be quantified and
their variation across the sample surface determined in an instrumentally
simple way. Results from a nearly dislocationfree Sdoped InP crystal and a
semiinsulating GaAs are presented; both display a clearly nonrandom
distribution of dislocations.
D. Lübbert, T. Baumbach, P. Mikulík, P. Pernot, L. Helfen, R. Köhler,
T.M. Katona, S. Keller, and S.P. DenBaars,
Local wing tilt analysis of laterally overgrown GaN by xray rocking curve
imaging,
Journal of Physics D 38, A50–A54 (2005).
Abstract
We report on recent advances in spatially resolved xray diffraction, extending
the technique known as rocking curve imaging down to 1–2 um
spatial resolution. Application to a set of gallium nitride samples grown by
epitaxial lateral overgrowth (ELO) shows the potential of the technique.
Quantitative information on crystallographic misorientations and lattice quality
can be obtained by direct imaging with high lateral resolution. Results from two
samples of ELOGaN grown on different substrates are compared. Tilt in individual
lateral periods of the ELO structure can be quantified. Local tilt fluctuations
are distinguished from macroscopic variations (curvature). The local lattice
quality can be investigated via the peak width of diffraction profiles recorded
in individual camera pixels. The peak broadening previously observed in laboratory
xray diffraction measurements is found to have (at least) two different reasons.
In both cases, peak broadening does not indicate a degradation in local crystalline
quality.
D. Korytár, T. Baumbach, C. Ferrari, L. Helfen, N. Verdi, P. Mikulík,
A. Kuběna, and P. Vagovič,
Monolithic twodimensional beam compressor for hard xray beams,
Journal of Physics D 38, A208–A212 (2005).
Abstract
Using asymmetric diffraction in grazing incidence or in grazing emergence it is
possible to expand or compress an xray beam in one dimension. Combining two
asymmetric diffractions with noncoplanar planes of diffraction it is possible
to obtain twodimensional beam expansion or compression. This paper reports on
a monolithic twodimensional xray beam compressor consisting of two
noncoplanar asymmetrically inclined {311} diffractors prepared in one silicon
crystal block and tested at Optics beamline BM05 at ESRF, Grenoble. The design
of the xray beam compressor, the results of beam tracing image simulation, the
experimental arrangement used for testing and the properties of the xray
microbeams formed are presented. For the beam energy of 9.5 keV 10 and
13times beam compression in two directions was observed. Using a metal grid in
the incident beam more than 400 microbeams smaller than 10 um and separated by
less than 5 um were obtained in the outgoing beam. A gain of up to 100 times
in intensity per unit area was obtained in comparison with the xray beam
magnifier geometry, demonstrating a real twodimensional beam compression.
L. Helfen, T. Baumbach, P. Mikulík, D. Kiel, P. Pernot, P. Cloetens,
and J. Baruchel,
Highresolution threedimensional imaging of flat objects by synchrotronradiation
computed laminography,
Applied Physics Letters 86, 071915 (2005).
Abstract
Computed laminography with synchrotron radiation is developed and carried out
for threedimensional imaging of flat, laterally extended objects with high
spatial resolution. Particular experimental conditions of a stationary
synchrotron source have been taken into account by a scanning geometry
different from that employed with movable conventional laboratory xray
sources. Depending on the mechanical precision of the sample manipulation
system, high spatial resolution down to the scale of 1 um can be attained
nondestructively, even for objects of large lateral size. Furthermore, high
beam intensity and the parallelbeam geometry enables easy use of monochromatic
radiation for optimizing contrast and reducing imaging artifacts. Simulations
and experiments on a test object demonstrate the feasibility of the method.
Application to the inspection of solder joints in a flipchip bonded device
shows the potential for quality assurance of microsystem devices.
L. Helfen, F. Dehn, L. Helfen, P. Mikulík, and T. Baumbach
Threedimensional imaging of cement microstructure evolution during hydration
,
Advances in Cement Research 17, 103–111 (2005).
Abstract
Synchrotron radiation is used for Xray computed tomography to characterise the
hydration process of Portland cement. Quantitative determination of the
threedimensional absorption coefficient distribution due to the use of
monochromatic radiation and the achieved high spatial resolution allows the
study of the spatial microstructure of cement volume during hydration. The
present study has demonstrated the potential of the method for realtime
imaging of the evolution of cement structure after solidification. The method
yields threedimensional (3D) images of the sample volume in a nondestructive
manner. Thus, by reiterated imaging of the same sample region at different
times, processes in the sample volume can be tracked. During cement hydration,
effects such as the formation and further evolution of microcracks and pores –
mainly related to autogeneous shrinkage – could be observed for the first time
in the cement volume with up to 1 μm resolution. Image analysis of the acquired
3D data sets allows the determination of the temporal evolution of
microporosity and of the fraction of contiguous pore volume for different water
: cement ratios of the initial cement paste.
O. Caha, P. Mikulík, J. Novák, V. Holý, S.C. Moss, A. Norman, A. Mascarenhas,
J.L. Reno, and B. Krause,
Spontaneous lateral modulation in shortperiod superlattices investigated
by grazingincidence xray diffraction,
Physical Review B 72, 035313 (2005).
Abstract
The process of spontaneous lateral composition modulation in shortperiod InAs
AlAs superlattices has been investigated by grazingincidence xray
diffraction. We have developed a theoretical description of xray scattering
from laterally modulated structures that makes it possible to determine the
lateral composition modulation directly without assuming any structure model.
From experimental intensity distributions in reciprocal space we have
determined the amplitudes of the modulation and its degree of periodicity and
their dependence on the number of superlattice periods. From the data it
follows that the modulation process cannot be explained by bunching of
monolayer steps and most likely, it is caused by stressdriven morphological
instabilities of the growing surface.
J. Hrdý, A. Kuběna, and P. Mikulík,
Aberrations of diffractive–refractive optics: Braggcase sagittal focusing
of multiple parabolic elements,
Journal of Physics D 38, 4325–4328 (2005).
Abstract
The diffractive–refractive optical device consisting of four crystals in
(+,–,–,+) setting with longitudinal parabolic grooves has a
geometrical aberration which influences the achievable focus size. This
aberration is discussed analytically by using a new, more precise formula for
the calculation of focusing distance, which respects the finite distance
between optical elements. The calculation of the intensity distribution
surrounding the focus is illustrated by a raytracing method based on the
dynamical theory of diffraction. It demonstrates an achievable focus size.
Finally we discuss that this aberration may be suppressed by the slight
narrowing of the groove profile. In particular, the parameter a in the equation
of parabola has to slightly grow with x. A practical application may
require an ultraprecise fabrication of the grooves.
D. Lübbert, P. Mikulík, P. Pernot, L. Helfen, M.D. Craven, S. Keller,
S. DenBaars, and T. Baumbach,
Xray microdiffraction imaging investigations of wing tilt in epitaxially
overgrown GaN,
physica status solidi (a) 203, 1733–1738 (2006).
Abstract
The crystalline quality in epitaxially laterally overgrown (ELO) GaN and the
amount of wing tilt is characterized on a local basis, with high spatial and
angular resolution. A method of fullfield Xray microdiffraction imaging,
termed rocking curve imaging, is used to record simultaneously a large set of
local Xray diffraction profiles originating from sample surface areas of
micrometer size. xomega maps of diffracted intensity allow to quantify the
amount of wing tilt in individual lateral ELO periods as well as to monitor the
fluctuations of tilt between adjacent periods. Automated shape analysis of the
full set of local rocking curves provides a means to quantitatively
characterize the local crystalline perfection of GaN. The ELO window and wing
regions can be clearly separated; comparison indicates an average improvement
of crystal quality by a factor 3–4 due to the lateral overgrowth process.
L. Helfen, A. Myagotin, P. Pernot, M. DiMichiel, P. Mikulík, A. Berthold,
and T. Baumbach,
Investigation of hybrid pixel detector arrays by synchrotronradiation imaging,
Nuclear instruments & methods in physics research A 563, 163–166 (2006).
Abstract
Synchrotronradiation imaging was applied to the nondestructive testing of
detector devices during their development cycle. Transmission imaging known as
computed laminography was used to examine the microstructure of the
interconnections in order to investigate the perfection of technological steps
necessary for hybrid detector production. A characterisation of the solder bump
microstructure can reveal production flaws such as missing or misaligned bumps,
voids in bumps or bridges and thus give valuable information about the bonding
process.
P. Mikulík, D. Lübbert, P. Pernot, L. Helfen, and T. Baumbach,
Crystallite misorientation analysis in semiconductor wafers and ELO samples by rocking curve imaging,
Applied Surface Science 253, 188–193 (2006).
Online fulltext.
Abstract
Rocking curve imaging is based on measuring a series of Braggreflection
digital topographs by monochromatic parallelbeam synchrotron radiation in
order to quantify local crystal lattice rotations within a large surface area
with high angular and high spatial resolution. In this paper we apply the
method to map local lattice tilts in two distinct semiconductor sample types
with lattice misorientations up to 0.5° and with spatial resolution from 30 um
down to 1 um. We analyse the measured surfacetilt data volumes for samples
with almost smoothly varying specific misoriented defect formation in GaAs
wafers and for an inherent subsurface grain structure of epitaxial lateral
overgrowth wings in GaN. Backprojected tilt maps and histograms provide both
local and global characteristics of the microcrystallinity.
L. Helfen, A. Myagotin, A. Rack, P. Pernot, P. Mikulík, M. Di Michiel, T. Baumbach,
Synchrotronradiation computed laminography for highresolution threedimensional
imaging of flat devices,
physica status solidi (a) 204, 2760–2765 (2007).
Online here.
Abstract
Synchrotronradiation computed laminography (SRCL) is developed as a method for
highresolution threedimensional (3D) imaging of regions of interest (ROIs) in
all kinds of laterally extended devices. One of the application targets is the
3D Xray inspection of microsystems. In comparison to computed tomography (CT),
the method is based on the inclination of the tomographic axis with respect to
the incident Xray beam by a defined angle. With the microsystem aligned
roughly perpendicular to the rotation axis, the integral Xray transmission on
the twodimensional (2D) detector does not change exceedingly during the scan.
In consequence, the integrity of laterally extended devices can be preserved,
what distinguishes SRCL from CT where ROIs have to be destructively extracted
(e.g. by cutting out a sample) before being imaged. The potential of the method
for threedimensional imaging of microsystem devices will be demonstrated by
examples of flipchip bonded and wirebonded devices.
J. Kuběna, A. Kuběna, O. Caha, and P. Mikulík,
Development of oxide precipitates in silicon: calculation of the distribution
function of the classical theory of nucleation by a nodalpoints approximation
,
J. Phys.: Condens. Matter 19, 496202–496212 (2007).
Online here.
Abstract
The classical theory of nucleation in solids is mathematically expressed by a
system of differential equations for temporal development of cluster
distribution (sizes and their concentration). Cluster sizes reach hundreds of
nanometers during long annealing times, requiring us to deal with up to
10^{7}–10^{8} differential equations. The full numerical
simulation grows linearly with the number of equations, making the numerical
solution extremely timeconsuming. In this paper we develop a nodalpoints
approximation method with a logarithmic efficiency, which allows us to
calculate the cluster distribution very quickly. The method is based on
modified Becker–Döring equations solved precisely only within a given set of
nodal points and approximated in between them. Availability of the method is
shown by monitoring the kinetics of oxygen precipitation in Czochralski silicon
for the case of a threestage annealing for 8 h at 600 °C+4 h at 800 °C+8 h at
1000 °C, where the number of monomers in the clusters reaches more than
2×10^{7}. Examples are discussed, mainly about the development of a
concentration gap and concentration wavelet of the cluster distribution and
about interstitial oxygen concentration.
P. Vagovič, D. Korytár, P. Mikulík, and C. Ferrari,
On the design of a monolithic 4bounce high resolution Xray monochromator
,
Nuclear Instruments and Methods in Physics Research Section B,
265, 599–604 (2007).
Online here.
Abstract
A monolithic monochromator (+n, −n, −m, +m) made of a single block of Ge
crystal designed for CoKα1 radiation was developed and tested numerically and
experimentally by means of Xray diffraction. The advantage of monolithic
devices is their mechanical stability and the alignment of such optics is much
easier than with polylithic optics, but the development of these devices is
rather demanding. The presented monochromator belongs to a group of coplanar
inline devices, which means that the input beam is parallel with the output
beam. For the estimation of the spectral and angular properties of a diffracted
beam of this monochromator (such as bandpass width, output divergence and input
acceptance) we used a numerical approach which we call spectralangular
function. It takes into account both the vertical and the horizontal divergence
of the input radiation and uses twobeam Xray dynamical theory of diffraction.
Experimentally, the monochromator was tested by means of Xray diffraction
(synchrotron radiation testing) and the results from this characterization are
presented. The influence of the vertical divergence on the spectral
distribution of the diffracted beam is discussed and compared with previously
published analytical results.
V. Holý, T. Baumbach, D. Lübbert, L. Helfen, M. Ellyan, P. Mikulík, S. Keller, S. P. DenBaars, and J. Speck,
Diffuse xray scattering from statistically inhomogeneous distributions
of threading dislocations beyond the ergodic hypothesis,
Physical Review B
77, 094102–94110 (2008).
Online here.
Abstract
Diffuse xray scattering from threading dislocations in epitaxial structures is
simulated numerically by a Monte Carlo method. The method allows one to
simulate diffraction curves for dislocation types, where macroscopic approaches
fail. That includes dislocation types for which analytical ensemble averaging
is not feasible as well as microdiffraction curves from small sample volumes.
In the latter case, the degree of statistic fluctuation of characteristic
features is determined. The Monte Carlo method makes it possible to correlate
quantitatively the widths of the microdiffraction curves to the densities of
various dislocation types. The potential of the method has been demonstrated by
a quantitative estimation of the density distribution of edge and screw
threading dislocations in laterally overgrown epitaxial GaN structures, which
is investigated by a fullfield microdiffraction imaging technique. Measuring
the asymptotic behavior of the microdiffraction curves allows one to conclude
on the prevailing type of threading dislocations.
D. Korytár, C. Ferrari, P. Mikulík, F. Germini, P. Vagovič, and T. Baumbach,
High Resolution 1D and 2D Crystal Optics Based on Asymmetric Diffractors,
chapter 29, book
Modern Developments in XRay and Neutron Optics, edited by
A. Erko, M. Idir, T. Krist, and A.G. Michette,
Springer (Springer Series in Optical Sciences), Berlin 2008.
Abstract
The development of high resolution Xray measurements and imaging in real and
reciprocal space is related to the improvement of the optical elements
available for use. Crystal diffractive optics still give the highest resolution
in reciprocal space and in energy, and progress has also been made in improving
resolution in real space. In this chapter a short introduction to the dynamical
theory behind crystal diffractors and their coupling is given and modern one
and twodimensional elements based on symmetric, asymmetric and inclined
diffractions are introduced. The design, the modeling of the output parameters
and the experimental results are presented for a special 2bounce Vshaped
monochromator, for a monolithic 4bounce monochromator and for a monolithic 2D
beam de/magnifier.
V. Áč, P. Perichta, D. Korytár, and P. Mikulík,
Thermal effects under synchrotron radiation power absorption,
chapter 30, book
Modern Developments in XRay and Neutron Optics, edited by
A. Erko, M. Idir, T. Krist, and A.G. Michette,
Springer (Springer Series in Optical Sciences), Berlin 2008.
Abstract
Analyses of the effects of silicon crystal beam heating under static and
dynamic synchrotron radiation power loads are presented. This research is
related to monochromator design and crystal optics in general. The aim of work
is to analyse the conditions for insertion of the crystal Xray optics into the
high flux primary beam of the synchrotron. Suggestions for the optimization of
the target geometry and cooling system arrangement are given.
D. Lübbert, T. Baumbach, V. Holý, P. Mikulík, L. Helfen, P. Pernot,
M. Ellyan, S. Keller, S. P. DenBaars, and J. Speck,
Microdiffraction imaging of dislocation densities in microstructured samples,
Europhysics Letters
82, 56002–56006 (2008).
Online here.
Abstract
A full field Xray microdiffraction technique is developed providing
simultaneously both micrometerresolved information of crystalline perfection
as well as statistical information about the macroscopically illuminated
sample. The method allows a detailed characterization of patterned substrates
grown by epitaxial lateral overgrowth. Local wing tilts and their fluctuation
over the sample area as well as the local and average number of grains in the
wings are determined, and the reduction of threading dislocation densities in
the grains of the ELO wings can be quantitatively estimated.
J. Humlíček and P. Mikulík,
ÚFKL PřF MU: polovodiče, nanostruktury, čisté prostory,
Československý časopis pro fyziku
58, 85 (2008).
See here.
Abstract
V tomto článku informujeme stručně o výzkumu v oblasti polovodičových materiálů
a struktur na ÚFKL, podrobněji pak o nově otevřené laboratoři polovodičů –
čistých prostorách pro křemíkovou technologii.
P. Kulha, A. Boura, M. Husák, P. Mikulík, M. Kučera, and S. Valenda,
Design and Fabrication of HighTemperature SOI StrainGauges,
In proceedings of the
7th International Conference on Advanced Semiconductor Devices and Microsystems
ASDAM 2008,
175–178 (2008).
See here.
Abstract
The following paper introduces the coventor ware design environment for SOI
based piezoresistive sensor design. Fabrication process and characterization of
designed sensors is also presented. The software package Coventor Ware has been
used for design of mechanical and electrical characteristics of the structure.
The tools enable design, modelling and successive modification of designed MEMS
structures. The program enables: drawing of 2D layout and its editing,
simulation of production process, generation of 3D model from 2D masks,
generation of network by the method offinite elements, solution of mechanical,
piezoresistive, thermal and further simulations. Simple passive elements
(strain sensitive resistors  piezoresistors) were fabricated on SIMOX SOI
substrates with sputtered AlCuSi metallization. Basic parameter extraction and
their temperature dependence were performed.
P. Mikulík, Z. Pokorná, B. Růžička, and S. Kozubek,
Projekt Středoevropské synchrotronové laboratoře – CESLAB,
Československý časopis pro fyziku
58, 244 (2008).
Abstract
Středoevropská synchrotronová laboratoř (Central European Synchrotron
Laboratory, CESLAB) byla navržena pro realizaci ze Strukturálních fondů
Evropské unie. Jedná se o moderní synchrotron třetí generace s energií
elektronů 3 GeV a průměrem 270 m pro experimenty se zářením v oblasti
od infračervené po rentgenovou se spuštěním v roce 2015. V tomto článku se
zabýváme důležitostí experimentů se synchrotronovým zářením pro vědu, výzkum a
aplikace a dále popisujeme stručně principy fungování urychlovacího komplexu
synchrotronu. Poté se konkrétně věnujeme příslušným parametrům CESLAB a nakonec
se zmiňujeme o vědeckých aplikacích navržených experimentálních stanic.
I. Bauer, P. Mikulík, and T. Baumbach,
Correctness of a particular solution of inverse problem in rocking curve imaging,
Physica Status Solidi A
206, 1860–1864 (2009).
Abstract
Local lattice misorientations on crystalline substrates can be visualized by
rocking curve imaging. Local deviations from Bragg peak positions are extracted
from a series of digital topographs recorded by a CCD detector under different
azimuths. Bragg peaks from surface regions such as crystallites with a larger
local misorientation overlap on the detector, which requires a backprojection
method in order to reconstruct the misorientation components on the sample
surface from the measured angular position on the detector planes. From
mathematical point of view, the reconstruction problem is at inverse problem.
In this paper, we formulate the forward and backprojection problems and we
prove the correctness of a particular solution. The usability of the method is
demonstrated on a phantom data set.
T. Baumbach and P. Mikulík,
Xray reflectivity by rough multilayers
(review article, pages 175–180 and 235–282).
XRay and Neutron Reflectivity: Principles
and Applications, edited by J. Daillant and A. Gibaud,
Berlin: Springer, Lecture Notes in Physics: 770 (2009).
Online at Springer
(chapter 6 and appendix to chapter 4); see also
table of contents.
D. Nečas, L. Zajíčková, D. Franta, P. Sťahel, P. Mikulík,
M. Meduňa, and M. Valtr,
Optical Characterization of UltraThin Iron and Iron Oxide Films,
eJournal of Surface Science and Nanotechnology
7 486–490 (2009).
Online here.
Abstract
Ultrathin films of ^{57}Fe deposited on silicon substrates and
SiO_{x}C_{y}H_{z} support layers and subsequently
oxidized in laboratory atmosphere are studied by two optical methods: the
combination of UV/VIS/NIR spectroscopic ellipsometry and spectrophotometry,
used to find layer thicknesses and optical constants, and Xray specular
reflectometry, used to obtain the electron density depth profile. The results
of both methods are compared and found to be in a relatively good agreement.
P. Oberta, P. Mikulík, M. Kittler, J. Hrdý, and L. Peverini,
Diffractiverefractive optics: lowaberration Braggcase focusing by precise parabolic surfaces,
Journal of Synchrotron Radiation
17, 36 (2010).
Online here.
Abstract
Based on analytical formulae calculations and raytracing simulations a
lowaberration focal spot with a high demagnification ratio was predicted for a
diffractive–refractive crystal optics device with parabolic surfaces. Two
Si(111) crystals with two precise parabolicshaped grooves have been prepared
and arranged in a dispersive position (+,−,−,+) with high asymmetry.
Experimental testing of the device at beamline BM05 at the ESRF provided a
focal spot size of 38.25 µm at a focal distance of 1.4 m for 7.31 keV. This
is the first experiment with a parabolicshaped groove; all previous
experiments were performed with circular grooves which introduced extreme
aberration broadening of the focal spot. The calculated and simulated focal
size was 10.8 µm at a distance of 1.1 m at 7.31 keV. It is assumed that the
difference between the measured and calculated/simulated focal spot size and
focal distance is due to insufficient surface quality and to alignment
imperfection.
D. Korytár, C. Ferrari, P. Mikulík, P. Vagovič, E. Dobročka, V. Áč, P. Konopka,
A. Erko, and N. Abrosimov,
Linearly graded GeSi beamexpanding/compressing Xray monochromator,
Journal of Applied Crystallography
43 176–178 (2010).
Online here.
Abstract
In standard singlecrystal Vchannel germanium (220) Xray
beamexpanding/compressing monochromators for Cu K[alpha]1 radiation, a total
beam expansion/compression of 5 and 10 corresponding to the asymmetry angles of
9 and 12° is achieved, respectively. Higher onedimensional beam
expansion/compression is achievable using larger angles of asymmetry at the
expense of a decrease in the total intensity. To increase the intensity, a
linearly graded Gerich GexSi1x single crystal was used to prepare a
monochromator with 15° asymmetry angles (total expansion/compression factor of
21) for Cu K[alpha]1 radiation. The Xray diffraction measurements show more
than three times higher peak intensity at the output compared with that of a
pure Ge monochromator.
M. Hovorka, F. Mika, P. Mikulík, and L. Frank,
Profiling NType Dopants in Silicon,
Materials Transactions
51 237–242 (2010).
Online here.
Abstract
Variously doped ntype structures (dopant concentration between
1.5*10^{16} cm^{3} and 1.5*10^{19} cm^{3})
on a lightly doped ptype silicon substrate (doped to 1.9*10^{15}
cm^{3}) have been examined by a photoemission electron microscope
equipped with a highpass energy filter and by an ultrahigh vacuum scanning
low energy electron microscope. High contrast have been observed between the
ntype areas and the ptype substrate and its monotone dependency on the doping
level of structures has been manifested. The relation between the energy
spectra of photoelectrons and the doping level has been studied, too. The
scanning electron microscope images obtained with the landing energy of the
primary beam in the low keV range exhibit contrasts similar to those appearing
in the full threshold photoemission micrographs.
V. Čech, S. Lichovníková, R. Trivedi, V. Peřina, J. Zemek, P. Mikulík, and O. Caha,
Plasma polymer films of tetravinylsilane modified by UV irradiation,
Surface and Coatings Technology
205 S177–S181 (2010).
Online here.
Abstract
Asdeposited plasma polymer films of tetravinylsilane were modified by UV
irradiation at ambient conditions. Surface and bulk spectroscopic techniques
confirmed significant changes in chemical composition and structure that
resulted in increased mechanical constants (Young's modulus, hardness) and
density of the material due to the formation of a stronger polymer network with
higher crosslinking. A decrease of the refractive index and extinction
coefficient of the UVirradiated material was caused by UVinduced chain
scission and subsequent oxidation of the plasma polymer network. The surface
morphology (RMS roughness) and wettability (surface free energy) of films can
be controlled by UV exposition time. The most intensive aging effect was
observed for the asdeposited film; in contrast, the 1000minUVirradiated
film appeared stable over 134 days. UV treatment can be characterized as an
effective tool for additional tailoring of plasma polymer films according to
their applications.
P. Oberta, P. Mikulík, J. Hrdý, and M. Kittler,
Highly asymmetric Laue focusing monochromator,
SRI 2009: The 10th international conference on synchrotron radiation
instrumentation:
AIP Conference Proceedings
1234 724–727 (2010).
Reference here.
Abstract
By using two highly asymmetric Laue crystals in a dispersive arrangement with a
circular profile (Ø 8 mm) we have created a sagittaly focusing Laue system for
the first time. The crystallographic planes (111) of the two Si crystals formed
an angle of 7.95° with the entrance surface. The crystals dimensions were 40
mm×20 mm and the diffracting surface was a 0.5 mm thick neck between the two
circular profiles. The 15.35 keV diffracted beam formed an angle of 0.55° with
the exit surface. The calculated focusing distance of the LaueLaue focusing
system was 14 m.
D. Korytár, C. Ferrari, P. Mikulík, P. Vagovič, E. Dobročka, V. Áč, P. Konopka, A. Erko,
N. Abrosimov, and Z. Zápražný,
1D Xray Beam Compressing Monochromators,
20th International Congress on XRay Optics and Microanalysis:
AIP Conference Proceedings
1221 59–62 (2010).
Reference here.
Abstract
A total beam compression of 5 and 10 corresponding to the asymmetry angles of
9° and 12° is achieved with V5 and V10 monochromators, respectively, in
standard single crystal pure germanium (220) Xray beam compressing (Vshaped)
monochromators for CuK1 radiation. A higher 1D compression of Xray beam is
possible using larger angles of asymmetry, however it is achieved at the
expense of the total intensity, which is decreased due to the refraction
effect. To increase the monochromator intensity, several ways are considered
both theoretically and experimentally. Linearly graded germanium rich
GexSi(1−x) single crystal was used to prepare a V21 single crystal
monochromator with 15° asymmetry angles (compression factor of 21). Its
temperature gradient version is discussed for CuK1 radiation. Xray diffraction
measurements on the graded GeSi monochromator showed more than 3times higher
intensity at the output compared with that of a pure Ge monochromator.
J. Hrdý, P. Mikulík, and P. Oberta,
Diffractiverefractive optics: (+,,,+) Xray crystal monochromator
with harmonics separation,
Journal of Synchrotron Radiation
18 229–301 (2011).
Reference here.
Abstract
A new kind of two channelcut crystals Xray monochromator in dispersive
(+,,,+) position which spatially separates harmonics is proposed. The
diffracting surfaces are oriented so that the diffraction is inclined. Owing to
refraction the diffracted beam is sagittally deviated. The deviation depends on
wavelength and is much higher for the first harmonics than for higher
harmonics. This leads to spatial harmonics separation. The idea is supported by
raytracing simulation.
C. Ferrari, F. Germini, D. Korytár, P. Mikulík, and L. Peverini,
Xray diffracted intensity for doublereflection channelcut Ge
monochromators at extremely asymmetric diffraction conditions,
Journal of Applied Crystallography
44 353–358 (2011).
Reference here.
Abstract
The width and integrated intensity of the 220 Xray doublediffraction profile
and the shift of the Bragg condition due to refraction have been measured in a
channelcut Ge crystal in an angular range near the critical angle of total
external reflection. The Bragg angle and incidence condition were varied by
changing the Xray energy. In agreement with the extended dynamical theory of
Xray diffraction, the integrated intensity of the double diffraction remained
almost constant, even for the grazingincidence condition very close to the
critical angle for total external reflection. A broadening of the diffraction
profile not predicted by the extended theory of Xray diffraction was observed
when the Bragg condition was at angles of incidence lower than 0.6 degrees.
Plane wave topographs revealed a contrast that could be explained by a slight
residual crystal surface undulation of 0.3 degrees due to etching to remove the
cutting damage and the increasing effect of refraction at glancing angles close
to the critical angle. These findings confirm that highly asymmetric
channelcut Ge crystals can also work as efficient monochromators or image
magnifiers at glancing angles close to the critical angle, the main limitation
being the crystal surface preparation.
P. Oberta, P. Mikulík, M. Kittler, and J. Hrdý,
Xray collimation by crystals with precise parabolic holes based on
diffractiverefractive optics,
Journal of Synchrotron Radiation
18 522–526 (2011).
Reference here.
Abstract
Two crystals with precise parabolic holes were used to demonstrate sagittal
beam collimation by means of a diffractiverefractive doublecrystal
monochromator. A new approach is introduced and beam collimation is
demonstrated. Two Si(333) crystals with an asymmetry angle of alpha = 15
degrees were prepared and arranged in a dispersive position (+,,,+). Based on
theoretical calculations, this doublecrystal setup should provide tunable
beam collimation within an energy range of 6.318.8 keV (Theta(B) = 7118.4
degrees). An experiment study was performed on BM05 at ESRF. Using 8.97 keV
energy, the beam profile at various distances was measured. The experimental
results are in good agreement with theoretical predictions. Owing to
insufficient harmonic suppression, the collimated (333) beam was overlapped by
horizontally diverging (444) and (555) beams.
L. Helfen, A. Myagotin, P. Mikulík, P. Pernot, A. Voropaev,
M. Elyyan, M. Di Michiel, J. Baruchel, and T. Baumbach,
On the implementation of computed laminography using synchrotron radiation,
Review of Scientific Instruments
82 063702 (2011).
Reference here.
Abstract
Hard x rays from a synchrotron source are used in this implementation of
computed laminography for threedimensional (3D) imaging of flat, laterally
extended objects. Due to outstanding properties of synchrotron light, high
spatial resolution down to the micrometer scale can be attained, even for
specimens having lateral dimensions of several decimeters. Operating either
with a monochromatic or with a white synchrotron beam, the method can be
optimized to attain high sensitivity or considerable inspection throughput in
synchrotron user and smallbatch industrial experiments. The article describes
the details of experimental setups, alignment procedures, and the underlying
reconstruction principles. Imaging of interconnections in flipchip and
wirebonded devices illustrates the peculiarities of the method compared to its
alternatives and demonstrates the wide application potential for the 3D
inspection and quality assessment in microsystem technology.
P. Vagovič, D. Korytár, P. Mikulík, A. Cecilia, C. Ferrari, Y. Yang,
D. Hanschke, E. Hamann, D. Pelliccia, T.A. Lafford, M. Fiederle, and T. Baumbach,
Inline Bragg magnifier based on Vshaped germanium crystals,
Journal of Synchrotron Radiation
18 753–760 (2011).
Reference here.
Abstract
In this work an Xray imaging system based on a recently developed inline
twodimensional Bragg magnifier composed of two monolithic Vshaped crystals
made of dislocationfree germanium is presented. The channelcut crystals were
used in onedimensional and in twodimensional (crossed) configurations in
imaging applications and allowed measurement of phasecontrast radiograms both
in the edgeenhanced and in the holographic regimes. The measurement of the
phase gradient in two orthogonal directions is demonstrated. The effective
pixel size attained was 0.17 um in the onedimensional configuration and 0.5
um in the twodimensional setting, offering a twofold improvement in spatial
resolution over devices based on silicon. These results show the potential for
applying Bragg magnifiers to imaging soft matter at high resolution with
reduced dose owing to the higher efficiency of Ge compared with Si.
P. Oberta, J. Hrdý, and P. Mikulík,
A proofofprinciple experiment of a novel harmonics separation optics
for synchrotron facilities,
Journal of Synchrotron Radiation
19 1012–1014 (2012).
Reference here.
Abstract
A proofofprinciple experiment of a novel harmonics separation optics for
synchrotron facilities is presented. The harmonic separator is a Si crystal cut
in an inclined geometry in which the impinging beam undergoes a
diffractiverefractive effect owing to the dispersive nature of Xray
refraction. A polychromatic beam containing higherorder energies is spatially
separated behind the separator into individual monochromatic diffraction spots.
A synchrotron experiment at a bendingmagnet beamline with 7 keV fundamental
energy is presented. The spot of the thirdorder harmonic of 21 keV is deviated
from the fundamental by 0.35 mm at a distance 1 m behind the device.
Z. Zápražný, D. Korytár, P. Mikulík, and V. Áč,
Processing of projections containing phase contrast in laboratory microcomputerized tomography imaging,
Journal of Applied Crystallography
46 933–938 (2013).
Reference here.
Abstract
Freespacepropagationbased imaging belongs to several techniques for
achieving phase contrast in the hard Xray range. The basic precondition is to
use an Xray beam with a high degree of coherence. Although the best sources of
coherent Xrays are synchrotrons, spatially coherent Xrays emitted from a
sufficiently small spot of laboratory microfocus or submicrofocus sources
allow the transfer of some of the modern imaging techniques from synchrotrons
to laboratories. Spatially coherent Xrays traverse a sample leading to a phase
shift. Beam deflection induced by the local change of refractive index may be
expressed as a darkbright contrast on the edges of the object in an Xray
projection. This phenomenon of edge enhancement leads to an increase in spatial
resolution of Xray projections but may also lead to unpleasant artefacts in
computerized tomography unless phase and absorption contributions are
separated. The possibilities of processing Xray images of lightweight objects
containing phase contrast using phaseretrieval methods in laboratory
conditions are tested and the results obtained are presented. For this purpose,
simulated and recorded Xray projections taken from a laboratory imaging system
with a microfocus Xray source and a highresolution CCD camera were processed
and a qualitative comparison of results was made.
D. Korytár, P. Vagovič, K. Végsö, P. Šiffalovič, E. Dobročka, W. Jark,
V. Áč, Z. Zápražný, C. Ferrari, A. Cecilia, E. Hamann, P. Mikulík,
T. Baumbach, M. Fiederle, and M. Jergel,
Potential use of V‐channel Ge(220) monochromators in X‐ray metrology and imaging,
Journal of Applied Crystallography
46 945–952 (2013).
Reference here.
Abstract
While channelcut crystals, in which the diffracting surfaces in an asymmetric
cut are kept parallel, can provide beam collimation and spectral beam shaping,
they can in addition provide beam compression or expansion if the cut is
Vshaped. The compression/expansion ratio depends in this case on the total
asymmetry factor. If the Ge(220) diffraction planes and a total asymmetry
factor in excess of 10 are used, the rocking curves of two diffractors will
have a sufficient overlap only if the second diffractor is tuned slightly with
respect to the first one. This study compares and analyses several ways of
overcoming this mismatch, which is due to refraction, when the CuK1 beam is
compressed 21fold in a V21 monochromator. A more than sixfold intensity
increase was obtained if the matching was improved either by a compositional
variation or by a thermal deformation. This provided an intensity gain compared
with the use of a simple slit in a symmetrical channelcut monochromator. The
first attempt to overcome the mismatch by introducing different types of Xray
prisms for the required beam deflection is described as well. The performance
of the Vshaped monochromators is demonstrated in two applications. A narrow
collimated monochromatic beam obtained in the beam compressing mode was used
for highresolution grazingincidence smallangle Xray scattering measurements
of a silicon sample with corrupted surface. In addition, a twodimensional
Bragg magnifier, based on two crossed V15 channel monochromators in beam
expansion mode and tuned by means of unequal asymmetries, was successfully
applied to highresolution imaging of test structures in combination with a
Medipix detector.
D. Korytár, P. Vagovič, C. Ferrari, P. Šiffalovič, M. Jergel, E. Dobročka,
Z. Zápražný, V. Áč, and P. Mikulík,
Processinduced inhomogeneities in higher asymmetry angle Xray monochromators,
Proceedings SPIE Volume 8848: Advances in XRay/EUV Optics and Components VIII,
edited by A. Khounsary, S. Goto, and C. Morawe,
88480U1–88480U8 (2013).
Reference here.
Abstract
Beam inhomogeneities of asymmetric Ge(220)based Vshaped and single bounce
monochromators have been studied both in metrological and imaging applications
for photon energies around 8 keV. Presence of growth striations in graded GeSi,
grains in single Cu crystal, and strains in thermally tuned Vchannel
monochromators observed in Xray topographs excludes these materials from
imaging applications. As for stochastic surface processing, chemomechanical
polishing (CMP) produces better surface homogeneity than chemical polish.
However, CMP is more difficult to be applied in Vchannels, where chemical
polishing is prefered. For comparison, measurements on surfaces processed by a
deterministic mechanical method of single point diamond turning (SPDT) have
shown SPDT to be a perspective technology. Again, to prepare deep grooves with
this technique is also a challenge, mainly for tool makers. Some process
induced features are observed as wavefield distortions in interference fringes.
Z. Zápražný, D. Korytár, P. Šiffalovič, M. Jergel, M. Demydenko,
P. Mikulík, E. Dobročka, C. Ferrari, P. Vagovič, and M. Mikloška,
Simulations and surface quality testing of high asymmetry angle Xray
crystal monochromators for advanced Xay imaging applications,
Proceedings SPIE Volume 9207: Advances in XRay/EUV Optics and Components IX,
edited by C. Morawe, A. Khounsary, and S. Goto,
0351011–03510112 (2014).
Reference here.
Abstract
Advanced Xray imaging techniques of weakly absorbing structures require an
increase of the sensitivity to small refractive angles considering that they
are based more on coherent Xray phase contrast than on Xray absorption one.
Simulations of diffraction properties of germanium (Ge) Xray crystal
monochromators and of analyzer based imaging (ABI) method were performed for
various asymmetry factors and several lattice plane orientations using an Xray
energy range from 8 keV to 20 keV. Using an appropriate phase/amplitude
retrieval method one can recover the phase information from the ABI image,
which is directly proportional to the projected electron density. We are using
germanium based optics for Xray imaging or image magnification. The use of Ge
crystals offers several advantages over silicon crystals. The integrated
reflectivity of Ge crystals is two to three times larger than that of Si
crystals. The spatial resolution of Ge magnifiers is typically two times better
than the spatial resolution of Si magnifiers. We used high asymmetry
diffractions to increase effectively the propagation distance and decrease the
effective pixel size of the detector, to achieve a sufficient magnification of
the sample and to improve coherence and increase output intensity. The most
important parameter of a highly asymmetric monochromators as image magnifiers
is the crystal surface quality. We have applied several crystal surface
finishing methods including conventional mechanical lapping, chemical
polishing, chemomechanical polishing and advanced nanomachining using single
point diamond turning (SPDT), and we have evaluated these methods by means of
AFM, diffractometry, reciprocal space mapping and others.
E. Barrier, F.M.B. Fernandes, M. Bujan, M.C. Feiters, A. Froideval, J. Ghijsen, T. Hase, M.A. Hough,
M. Jergel, I. Jimenez, T. Kajander, A. Kikas, M. Kokkinidis, L. Kover, H.B. Larsen, D.M. Lawson,
K. LawniczakJablonska, C. Mariani, P. Mikulik, J. Monnier, S. Morera, C. McGuinness, P. MüllerBuschbaum,
M.M. Nielson, U. Pietsch, M. Tromp, M. Simon, J. Stangl, and G. Zanotti,
The benefit of the European User Community from transnational access to national radiation facilities,
Journal of Synchrotron Radiation 21 638–639 (2014).
Reference here.
Abstract
Transnational access (TNA) to national radiation sources is presently provided
via programmes of the European Commission by BIOSTRUCTX and CALIPSO with a
major benefit for scientists from European countries. Entirely based on
scientific merit, TNA allows all European scientists to realise synchrotron
radiation experiments for addressing the Societal Challenges promoted in
HORIZON2020. In addition, by TNA all European users directly take part in the
development of the research infrastructure of facilities. The mutual
interconnection of users and facilities is a strong prerequisite for future
development of the research infrastructure of photon science. Taking into
account the present programme structure of HORIZON2020, the European
Synchrotron User Organization (ESUO) sees considerable dangers for the
continuation of this successful collaboration in the future.
Z. Zápražný, D. Korytár, M. Jergel, P. Šiffalovič, E. Dobročka, P. Vagovič, C. Ferrari, P. Mikulík, M. Demydenko,
and M. Mikloška,
Calculations and surface quality measurements of highasymmetry angle xray crystal monochromators
for advanced xray imaging and metrological applications,
Optical Engineering 54 035101 (2015).
Reference here.
Abstract
We present the numerical optimization and the technological development
progress of xray optics based on asymmetric germanium crystals. We show the
results of several basic calculations of diffraction properties of germanium
xray crystal monochromators and of an analyzerbased imaging method for
various asymmetry factors using an xray energy range from 8 to 20 keV. The
important parameter of highly asymmetric monochromators as image magnifiers or
compressors is the crystal surface quality. We have applied several crystal
surface finishing methods, including advanced nanomachining using singlepoint
diamond turning (SPDT), conventional mechanical lapping, chemical polishing,
and chemomechanical polishing, and we have evaluated these methods by means of
atomic force microscopy, diffractometry, reciprocal space mapping, and others.
Our goal is to exclude the chemical etching methods as the final processing
technique because it causes surface undulations. The aim is to implement very
precise deterministic methods with a control of surface roughness down to
0.1 nm. The smallest roughness (∼0.3 nm), best planarity, and absence of the
subsurface damage were observed for the sample which was machined using an SPDT
with a feed rate of 1 mm/min and was consequently polished using a fine
polishing 15min process with a solution containing SiO2 nanoparticles
(20 nm).
Z.J. Li, A.N. Danilewsky, L. Helfen, P. Mikulík, D. Haenschke, J. Wittge,
D. Allen, P. McNally, and T. Baumbach,
Local strain and defects in silicon wafers due to nanoindentation revealed by fullfield Xray microdiffraction imaging,
Journal of Synchrotron Radiation 22 1083–1090 (2015).
Reference here.
Abstract
Quantitative characterization of local strain in silicon wafers is critical in
view of issues such as wafer handling during manufacturing and strain
engineering. In this work, fullfield Xray microdiffraction imaging using
synchrotron radiation is employed to investigate the longrange distribution of
strain fields in silicon wafers induced by indents under different conditions
in order to simulate wafer fabrication damage. The technique provides a
detailed quantitative mapping of strain and defect characterization at the
micrometer spatial resolution and holds some advantages over conventional
methods.
K. Végsö, M. Jergel, P. Šiffalovič, E. Majková, D. Korytár, Z. Zápražný,
P. Mikulík, and P. Vagovič,
Towards highflux Xray beam compressing channelcut monochromators,
Journal of Applied Crystallography 49 1885–1892 (2016).
Reference here.
Abstract
The issue of a highflux Xray beam compressing channelcut monochromator for
applications in Xray metrology is addressed. A Ge(111) compressor with
compression ratio 20.3 was designed on the principle of a combination of
symmetric and highly asymmetric diffractions. A pilot application of the
singlepoint diamond technology (SPDT) to finish active surfaces of Xray
optics was tested, providing 50% flux enhancement as compared to a Ge(220)
counterpart prepared by traditional surface treatment. This is much more than
the theoretical 22% forecast and shows the potential of SPDT for preparation of
highflux Xray compressors with a high compression ratio, where highly
asymmetric diffraction with a very low exit angle is inevitable. The
implications for efficient collection of Xrays from microfocus Xray sources
are discussed. A comparison of Ge compressors with Ge parallel channelcut
monochromators combined with a 50 µm slit shows the several times higher flux
of the former, making them applicable in Xray diffraction experiments at
medium resolution. Furthermore, the Ge(111) compressor was tested as a
collimator in highresolution grazingincidence smallangle Xray scattering
(GISAXS) measurements of surface gratings, providing experimental resolution
close to 400 nm. This is ~100 nm smaller than that achieved with the Ge(220)
compressor but still approximately twice that of commercial SAXS/GISAXS
laboratory setups.
Last update: 26. 1. 20167