Publications by Petr Mikulík

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

  1. Difrakce na kvaziperiodických supermřížkách (diploma thesis, 1993)
  2. La caracterisation du systeme epitaxial tungstene/saphir par la diffusion des rayons X (diploma thesis, 1993)
  3. X-ray diffraction on Fibonacci superlattices (article, Acta Cryst. 1995)
  4. Scattering on aperiodic superlattices (article, in proceedings "Beyond Quasicrystals" 1995)
  5. Epitaxial growth and characterization of Y2Co17(0001) thin films deposited on W(110) (article, J. Appl. Phys. 1995)
  6. Multiple diffraction of particles on a system of point scatterers as an exactly soluble problem using the Ewald concept (article, J. Phys. (UK) 1996)
  7. Theoretical description of multiple crystal arrangements (article, in proceedings book 1996)
  8. Dynamical theory of diffraction of particles: Ewald's approach (article, Scripta fac. sci. nat. univ. masaryk. brun. 1996)
  9. X-Ray Reflectivity from Planar and Structured Multilayers (PhD thesis, 1997)
  10. X-ray reflection by multilayer surface gratings, (article, Physica B 1998)
  11. Highly regular self-organization of step bunches during growth of SiGe on Si(113) (article, Appl. Phys. Lett. 1998)
  12. X-ray reflection by rough multilayer gratings. Dynamical and kinematical scattering (article, Phys. Rev. B 1999)
  13. Structural characterization of a lamellar W/Si multilayer grating, (article, J. Appl. Phys. 1999)
  14. Structural characterization of lamellar multilayer gratings by X-ray reflectivity and scanning electron microscopy (article, J. Phys. D 1999)
  15. Strain relaxation in periodic arrays of Si/SiGe quantum wires determined by coplanar high resolution x-ray diffraction and grazing incidence diffraction (article, J. Phys. D 1999)
  16. High-resolution x-ray diffraction on self-organized step bunches of Si1-xGex grown on (113)-oriented Si (article, J. Phys. D 1999)
  17. X-ray reflectivity by rough multilayers (review article, proceedings book X-Ray and Neutron Reflectivity: Principles and Applications, Springer 1999)
  18. X-ray diffraction from quantum wires and quantum dots (article, J. Mater. Sci.: Mat. in Electr. 1999)
  19. The crystal truncation rod scattering of neutrons and the multiwave dynamical theory of diffraction (article, J.Phys.: Condens. Matter 1999)
  20. Self-assembled carbon-induced germanium quantum dots studied by grazing-incidence small-angle x-ray scattering (article, Appl. Phys. Lett. 1999)
  21. Multilayer gratings for X-UV optics (article, acta physica slovaca 2000)
  22. Nearly perfect 3D ordering in IV-VI quantum dot superlattices with ABCABC... vertical stacking sequence (article, Physica E 2000)
  23. Coplanar and non-coplanar x-ray reflectivity characterization of lateral W/Si multilayer gratings, (article, J. Phys. D 2001)
  24. X-ray diffraction and reflectivity analysis of GaAs/InGaAs free-standing trapezoidal quantum wires, (article, J. Phys. D 2001)
  25. Coplanar and non-coplanar x-ray reflectivity characterization of lateral W/Si multilayer gratings (article, Sup. y Vac. 2001)
  26. Strain in buried quantum wires: Analytical calculations and x-ray diffraction study (article, Phys. Rev. B 2002)
  27. Advanced X-ray diffraction imaging techniques for semiconductor wafer characterisation (article, Materials Structure 2002)
  28. Synchrotron area diffractometry as a tool for spatial high-resolution three-dimensional lattice misorientation mapping (article, J. Phys. D: Appl. Phys. 2003)
  29. Two-dimensional x-ray magnification based on a monolithic beam conditioner (article, J. Phys. D: Appl. Phys. 2003)
  30. Determination of lattice plane curvature and dislocation Burgers vector density in crystals by rocking curve imaging technique (article, Proceedings SPIE Volume 5195 2003)
  31. Micro- and nano-NDE in the laboratory for acoustic diagnosis and quality assurance (article, Proceedings SPIE Volume 5392 2004)
  32. Synchrotron-radiation X-ray tomography: a method for 3D imaging of cement microstructure and its evolution during hydration (article, Proceedings SANACE 2004)
  33. Distribution and Burgers vectors of dislocations in semiconductor wafers investigated by rocking-curve imaging (article, J. Appl. Cryst. 2005)
  34. Local wing tilt analysis of laterally overgrown GaN by x-ray rocking curve imaging (article, J. Phys. D 2005)
  35. Monolithic two-dimensional beam compressor for hard x-ray beams (article, J. Phys. D 2005)
  36. High-resolution three-dimensional imaging of flat objects by synchrotron-radiation computed laminography (article, Appl. Phys. Lett. 2005)
  37. Three-dimensional imaging of cement microstructure evolution during hydration (article, Advances in Cement Research 2005)
  38. Spontaneous lateral modulation in short-period superlattices investigated by grazing-incidence x-ray diffraction (article, Physical Review B 2005)
  39. Aberrations of diffractive–refractive optics: Bragg-case sagittal focusing of multiple parabolic elements (article, J. Phys. D 2005)
  40. X-ray microdiffraction imaging investigations of wing tilt in epitaxially overgrown GaN (article, physica status solidi (a) 2006)
  41. Investigation of hybrid pixel detector arrays by synchrotron-radiation imaging (article, Nuclear instruments & methods in physics research A 2006).
  42. Crystallite misorientation analysis in semiconductor wafers and ELO samples by rocking curve imaging (article, Applied Surface Science 2006)

  43. Synchrotron-radiation computed laminography for high-resolution three-dimensional imaging of flat devices (article, physica status solidi (a) 2007).
  44. Development of oxide precipitates in silicon: calculation of the distribution function of the classical theory of nucleation by a nodal-points approximation (article, J. Phys.: Condens. Matter 2007)
  45. On the design of a monolithic 4-bounce high resolution X-ray monochromator (article, Nuclear Instruments and Methods in Physics Research B 2007).
  46. Diffuse x-ray scattering from statistically inhomogeneous distributions of threading dislocations beyond the ergodic hypothesis (article, Physics Review B 2008)
  47. High Resolution 1D and 2D Crystal Optics Based on Asymmetric Diffractors (chapter, book Modern Developments in X-Ray and Neutron Optics, Springer 2008)
  48. Thermal effects under synchrotron radiation power absorption (chapter, book Modern Developments in X-Ray and Neutron Optics, Springer 2008)
  49. Microdiffraction imaging of dislocation densities in microstructured samples (article, Europhysics Letters 2008)
  50. ÚFKL PřF MU: polovodiče, nanostruktury, čisté prostory (article, Československý časopis pro fyziku 2008)
  51. Design and Fabrication of High-Temperature SOI Strain-Gauges (article, in proceedings 2008)
  52. Projekt Středoevropské synchrotronové laboratoře – CESLAB (article, Československý časopis pro fyziku 2008)
  53. Correctness of a particular solution of inverse problem in rocking curve imaging (article, Physica Status Solidi A 2009)
  54. X-ray reflectivity by rough multilayers (chapter in book X-Ray and Neutron Reflectivity: Principles and Applications, Springer 2009)
  55. Optical Characterization of Ultra-Thin Iron and Iron Oxide Films (article, e-Journal of Surface Science and Nanotechnology 2009)
  56. Diffractive-refractive optics: low-aberration Bragg-case focusing by precise parabolic surfaces (article, Journal of Synchrotron Radiation 2010)
  57. Linearly graded GeSi beam-expanding/compressing X-ray monochromator (article, Journal of Applied Crystallography 2010)
  58. Profiling N-Type Dopants in Silicon (article, Materials Transactions 2010)
  59. Plasma polymer films of tetravinylsilane modified by UV irradiation, (article, Surface and Coatings Technology 2010)
  60. Highly asymmetric Laue focusing monochromator (article, AIP Conference Proceedings 2010)
  61. 1D X-ray Beam Compressing Monochromators (article, AIP Conference Proceedings 2010)
  62. Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation (article, Journal of Synchrotron Radiation 2011)
  63. X-ray diffracted intensity for double-reflection channel-cut Ge monochromators at extremely asymmetric diffraction conditions (article, Journal of Applied Crystallography 2011)
  64. X-ray collimation by crystals with precise parabolic holes based on diffractive-refractive optics (article, Journal of Synchrotron Radiation 2011)
  65. On the implementation of computed laminography using synchrotron radiation (article, Review of Scientific Instruments 2011)
  66. In-line Bragg magnifier based on V-shaped germanium crystals (article, Journal of Synchrotron Radiation 2011)
  67. A proof-of-principle experiment of a novel harmonics separation optics for synchrotron facilities (article, Journal of Synchrotron Radiation 2012)
  68. Processing of projections containing phase contrast in laboratory micro-computerized tomography imaging (article, Journal of Applied Crystallography 2013)
  69. Potential use of V‐channel Ge(220) monochromators in X‐ray metrology and imaging (article, Journal of Applied Crystallography 2013)
  70. Process-induced inhomogeneities in higher asymmetry angle X-ray monochromators (article, Proceedings SPIE Volume 8848 2013)
  71. Simulations and surface quality testing of high asymmetry angle X-ray crystal monochromators for advanced X-ay imaging applications (article, Proceedings SPIE Volume 9207 2014)
  72. The benefit of the European User Community from transnational access to national radiation facilities (article, Journal of Synchrotron Radiation 2014)
  73. Calculations and surface quality measurements of high-asymmetry angle x-ray crystal monochromators for advanced x-ray imaging and metrological applications (article, Optical Engineering 2015)
  74. Local strain and defects in silicon wafers due to nanoindentation revealed by full-field X-ray microdiffraction imaging (article, Journal of Synchrotron Radiation 2015)
  75. Towards high-flux X-ray beam compressing channel-cut 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 X-Ray 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, X-ray 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 X-ray 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 X-ray diffraction theories for studying SLs will be presented. In the third part both the kinematical theory and the semi-kinematical 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 X-ray 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 camera-ready 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 Y2Co17(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: "X-ray 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 semi-infinite crystal is studied using the T-matrix formalism of Ewald's dynamical theory of diffraction. Using from the beginning the two-dimensional translational symmetry of the crystal bordered by a surface, simple exact many-beam analytical formulae for the intensities of the reflected waves are deduced, whereby the Ewald sphere is replaced by "the gamma-diagrams" and the usual three-dimensional dispersion surface by two-dimensional "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 many-beam 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 self-consistent theory of multiple scattering the reflection of the scalar plane wave on an ideal semi-infinite crystal formed by point-like diffraction centres is studied. Exact many-beam 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 short-wavelength region. The obtained expression for the reflectivity is effective for the so-called 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: X-ray Reflectivity From Planar And Structured Multilayers, PhD. thesis. Université Joseph Fourier (Grenoble) and Masaryk University (Brno), 1997.

Abstract
The X-ray 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 distorted-wave Born approximation, the dynamical theory and various approximations of the dynamical theory (the single-reflection approximation, the two-beam approximation and the multiple-beam 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 X-ray reflection by multilayer surface gratings, Physica B 248, 381–386 (1998).

Abstract
X-ray 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 X-ray 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 self-organization of step bunches during growth of SiGe on Si(113), Appl. Phys. Lett. 73, 1535–1537 (1998).



P. Mikulík and T. Baumbach, X-ray reflection by rough multilayer gratings. Dynamical and kinematical scattering. Phys. Rev. B 59, 7632–7643 (1999).

Abstract
X-ray 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 non-zero 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 X-ray 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 X-ray 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 x-ray diffraction and grazing incidence diffraction, J. Phys. D 32, A224–A229 (1999).

Abstract
Elastic relaxation in dry-etched periodic wires fabricated from molecular beam epitaxy grown Si/SiGe multilayers was studied by coplanar and grazing incidence (GID) high-resolution x-ray 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 fabrication-induced layer covering the wire surfaces, modifies the strain distribution. Using GID, the geometrical shape of the wires and their in-plane 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, High-resolution x-ray diffraction on self-organized step bunches of Si1-xGex 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 x-ray diffraction, x-ray 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/Si1-xGex multilayers. X-ray 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, X-ray reflectivity by rough multilayers (review article, pages 155–161 and 232–280). Proceedings of the Ecole Française de Reflectivité (Luminy, France, 1997): X-Ray 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 X-ray 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 X-ray reflectivity experiments ...................... 17
      8.3.1 Experimental setup ..................................... 17
      8.3.2 Experimental scans ..................................... 19
  8.4 Specular X-ray 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 Non-specular X-ray reflection ................................ 31
      8.5.1 Interfaces with a Gaussian roughness profile ........... 31
      8.5.2 The main scattering features of non-specular reflection
            by rough multilayers ................................... 35
      8.5.3 Stepped surface and interfaces ......................... 40
      8.5.4 Non-coplanar NSXR ...................................... 43
  8.6 Interface roughness in surface sensitive diffraction methods . 44
  8.7 X-ray 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, X-ray 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 non-coplanar 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, Self-assembled carbon-induced germanium quantum dots studied by grazing-incidence small-angle x-ray scattering, Applied Physics Letters 74, 3785–3787 (1999).

Abstract
We present a structural investigation of buried C-induced Ge quantum dot multilayers grown on (001) Si by molecular-beam epitaxy. Using grazing-incidence small-angle x-ray 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 X-UV 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 X-ray 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 X-ray 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 non-specular X-ray reflectivities at wavelength 0.15418 nm were measured on one of the samples. The dynamical theory of X-ray 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 X-ray 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. Salamanca-Riba, Nearly perfect 3D ordering in IV-VI quantum dot superlattices with ABCABC... vertical stacking sequence, Physica E 7, 870–875 (2000).

Abstract
Self-organization of PbSe islands in epitaxial PbSe/Pb1-xEuxTe superlattices is shown to result in a spontaneous three-dimensional ordering of the PbSe dots in a trigonal lattice with a fee-like ABCABC vertical stacking sequence. From X-ray 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 non-coplanar x-ray 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 x-ray reflectivity in the coplanar and non-coplanar modes using a scintillation detector and a two-dimensional gas-filled detector, respectively. Three-dimensional 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, X-ray diffraction and reflectivity analysis of GaAs/InGaAs free-standing trapezoidal quantum wires, J. Phys. D: Appl. Phys. 34, A179–A182 (2001).

Abstract
Combined x-ray diffraction and reflectivity experiments have been performed on free-standing trapezoidal GaAs/InGaAs quantum wires using a conventional x-ray 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 x-ray 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 set-up without the influence of strain. All small-angle as well as wide-angle scattering experimental results went in to the mutually consistent estimate of the sample properties. The experiments performed for a conventional x-ray 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 non-coplanar x-ray 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 X-ray 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 non-coplanar geometries., the nominal lateral and normal periods being 800 nm and 8 nm, respectively. The coplanar measurements were evaluated within the dynamical theory of X-ray 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 non-coplanar measurements were evaluated qualitatively using three-dimensional constructions in the reciprocal space. The advantage of the technique used is its non-destructive 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 x-ray diffraction study, Phys. Rev. B 66, 035310-1–035310-7 (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 x-ray-diffraction 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 X-ray 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 high-resolution X-ray 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 ultra-thin wafers. We present synchrotron topography and synchrotron area diffractometry methods to analyse qualitatively and quantitatively: dislocations and lineages, micro-defects and micro-cracks, 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 high-resolution three-dimensional lattice misorientation mapping, J. Phys. D: Appl. Phys. 36, A74–A78 (2003).

Abstract
We have developed a high-resolution diffraction imaging method for determination of the complete three-dimensional rotational local lattice misorientation of crystalline samples. The method, called synchrotron area diffractometry, is based on recording double-crystal diffraction rocking scans in three mutually non-coplanar scattering planes with a two-dimensional area detector. The subsequent multiple-peak 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 semi-insulating GaAs(001) wafer.


D. Korytár, P. Mikulík, C. Ferrari, J. Hrdý, T. Baumbach, A. Freund, and A. Kuběna, Two-dimensional x-ray magnification based on a monolithic beam conditioner, J. Phys. D: Appl. Phys. 36, A65–A68 (2003).

Abstract
In x-ray imaging and beam conditioning it is useful to magnify or demagnify the x-ray 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 x-ray beam in one direction. Combining two such diffractors with mutually perpendicular planes of diffraction even two-dimensional 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 x-ray beam in two directions. In this paper, a new magnifying monolithic optical device for a two-dimensional magnification of 25 at 10 keV, based on two noncoplanar asymmetrically inclined {311} diffractors, was designed and made from a single silicon crystal. A ray-tracing 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 semi-insulating GaAs wafer crystals has been investigated using the method of X-ray 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 (σ-π 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 nano-NDE in the laboratory for acoustic diagnosis and quality assurance, Proceedings SPIE Volume 5392: Testing, Reliability, and Application of Micro- and Nano-Material 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 X-ray 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 nano-meter 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, Synchrotron-radiation X-ray 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 x-ray tomography as an experimental imaging method to study the microstructural evolution during cement hydration. The present work demonstrates the potential of synchrotron-radiation 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 rocking-curve imaging, Journal of Applied Crystallography 38, 91–96 (2005).

Abstract
The method called rocking-curve 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 X-ray rocking-curve analysis and digital X-ray 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 dislocation-free S-doped InP crystal and a semi-insulating GaAs are presented; both display a clearly non-random 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 x-ray rocking curve imaging, Journal of Physics D 38, A50–A54 (2005).

Abstract
We report on recent advances in spatially resolved x-ray 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 ELO-GaN 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 x-ray 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 two-dimensional beam compressor for hard x-ray 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 x-ray beam in one dimension. Combining two asymmetric diffractions with non-coplanar planes of diffraction it is possible to obtain two-dimensional beam expansion or compression. This paper reports on a monolithic two-dimensional x-ray beam compressor consisting of two non-coplanar asymmetrically inclined {311} diffractors prepared in one silicon crystal block and tested at Optics beamline BM05 at ESRF, Grenoble. The design of the x-ray beam compressor, the results of beam tracing image simulation, the experimental arrangement used for testing and the properties of the x-ray microbeams formed are presented. For the beam energy of 9.5 keV 10- and 13-times 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 x-ray beam magnifier geometry, demonstrating a real two-dimensional beam compression.


L. Helfen, T. Baumbach, P. Mikulík, D. Kiel, P. Pernot, P. Cloetens, and J. Baruchel, High-resolution three-dimensional imaging of flat objects by synchrotron-radiation computed laminography, Applied Physics Letters 86, 071915 (2005).

Abstract
Computed laminography with synchrotron radiation is developed and carried out for three-dimensional 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 x-ray 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 parallel-beam 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 flip-chip bonded device shows the potential for quality assurance of microsystem devices.


L. Helfen, F. Dehn, L. Helfen, P. Mikulík, and T. Baumbach Three-dimensional imaging of cement microstructure evolution during hydration , Advances in Cement Research 17, 103–111 (2005).

Abstract
Synchrotron radiation is used for X-ray computed tomography to characterise the hydration process of Portland cement. Quantitative determination of the three-dimensional 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 real-time imaging of the evolution of cement structure after solidification. The method yields three-dimensional (3-D) images of the sample volume in a non-destructive 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 3-D 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 short-period superlattices investigated by grazing-incidence x-ray diffraction, Physical Review B 72, 035313 (2005).

Abstract
The process of spontaneous lateral composition modulation in short-period InAs AlAs superlattices has been investigated by grazing-incidence x-ray diffraction. We have developed a theoretical description of x-ray 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 stress-driven morphological instabilities of the growing surface.


J. Hrdý, A. Kuběna, and P. Mikulík, Aberrations of diffractive–refractive optics: Bragg-case 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 ray-tracing 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 ultra-precise fabrication of the grooves.



D. Lübbert, P. Mikulík, P. Pernot, L. Helfen, M.D. Craven, S. Keller, S. DenBaars, and T. Baumbach, X-ray 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 full-field X-ray microdiffraction imaging, termed rocking curve imaging, is used to record simultaneously a large set of local X-ray diffraction profiles originating from sample surface areas of micrometer size. x-omega 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 synchrotron-radiation imaging, Nuclear instruments & methods in physics research A 563, 163–166 (2006).

Abstract
Synchrotron-radiation imaging was applied to the non-destructive 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 Bragg-reflection digital topographs by monochromatic parallel-beam 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 surface-tilt 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. Back-projected 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, Synchrotron-radiation computed laminography for high-resolution three-dimensional imaging of flat devices, physica status solidi (a) 204, 2760–2765 (2007).
Online here.

Abstract
Synchrotron-radiation computed laminography (SRCL) is developed as a method for high-resolution three-dimensional (3D) imaging of regions of interest (ROIs) in all kinds of laterally extended devices. One of the application targets is the 3D X-ray 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 X-ray beam by a defined angle. With the microsystem aligned roughly perpendicular to the rotation axis, the integral X-ray transmission on the two-dimensional (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 three-dimensional imaging of microsystem devices will be demonstrated by examples of flip-chip bonded and wire-bonded 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 nodal-points 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 107–108 differential equations. The full numerical simulation grows linearly with the number of equations, making the numerical solution extremely time-consuming. In this paper we develop a nodal-points 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 three-stage 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 2×107. 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 4-bounce high resolution X-ray 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 X-ray 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 in-line 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 spectral-angular function. It takes into account both the vertical and the horizontal divergence of the input radiation and uses two-beam X-ray dynamical theory of diffraction. Experimentally, the monochromator was tested by means of X-ray 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 x-ray scattering from statistically inhomogeneous distributions of threading dislocations beyond the ergodic hypothesis, Physical Review B 77, 094102–94110 (2008).
Online here.

Abstract
Diffuse x-ray 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 full-field 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 X-Ray 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 X-ray 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 two-dimensional 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 2-bounce V-shaped monochromator, for a monolithic 4-bounce 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 X-Ray 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 X-ray 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 X-ray microdiffraction technique is developed providing simultaneously both micrometer-resolved 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 High-Temperature SOI Strain-Gauges, 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 back-projection 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 back-projection 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, X-ray reflectivity by rough multilayers (review article, pages 175–180 and 235–282). X-Ray 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 Ultra-Thin Iron and Iron Oxide Films, e-Journal of Surface Science and Nanotechnology 7 486–490 (2009).
Online here.

Abstract
Ultra-thin films of 57Fe deposited on silicon substrates and SiOxCyHz 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 X-ray 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, Diffractive-refractive optics: low-aberration Bragg-case focusing by precise parabolic surfaces, Journal of Synchrotron Radiation 17, 36 (2010).
Online here.

Abstract
Based on analytical formulae calculations and ray-tracing simulations a low-aberration 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 parabolic-shaped 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 parabolic-shaped 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 beam-expanding/compressing X-ray monochromator, Journal of Applied Crystallography 43 176–178 (2010).
Online here.

Abstract
In standard single-crystal V-channel germanium (220) X-ray beam-expanding/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 one-dimensional 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 Ge-rich GexSi1-x 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 X-ray 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 N-Type Dopants in Silicon, Materials Transactions 51 237–242 (2010).
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Abstract
Variously doped n-type structures (dopant concentration between 1.5*1016 cm-3 and 1.5*1019 cm-3) on a lightly doped p-type silicon substrate (doped to 1.9*1015 cm-3) have been examined by a photoemission electron microscope equipped with a high-pass energy filter and by an ultra-high vacuum scanning low energy electron microscope. High contrast have been observed between the n-type areas and the p-type 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).
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Abstract
As-deposited 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 cross-linking. A decrease of the refractive index and extinction coefficient of the UV-irradiated material was caused by UV-induced 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 as-deposited film; in contrast, the 1000-min-UV-irradiated 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 Laue-Laue 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 X-ray Beam Compressing Monochromators, 20th International Congress on X-Ray 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 V-5 and V-10 monochromators, respectively, in standard single crystal pure germanium (220) X-ray beam compressing (V-shaped) monochromators for CuK1 radiation. A higher 1D compression of X-ray 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 V-21 single crystal monochromator with 15° asymmetry angles (compression factor of 21). Its temperature gradient version is discussed for CuK1 radiation. X-ray diffraction measurements on the graded GeSi monochromator showed more than 3-times higher intensity at the output compared with that of a pure Ge monochromator.


J. Hrdý, P. Mikulík, and P. Oberta, Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation, Journal of Synchrotron Radiation 18 229–301 (2011).
Reference here.

Abstract
A new kind of two channel-cut crystals X-ray 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 ray-tracing simulation.


C. Ferrari, F. Germini, D. Korytár, P. Mikulík, and L. Peverini, X-ray diffracted intensity for double-reflection channel-cut 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 X-ray double-diffraction profile and the shift of the Bragg condition due to refraction have been measured in a channel-cut 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 X-ray energy. In agreement with the extended dynamical theory of X-ray diffraction, the integrated intensity of the double diffraction remained almost constant, even for the grazing-incidence condition very close to the critical angle for total external reflection. A broadening of the diffraction profile not predicted by the extended theory of X-ray 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 channel-cut 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, X-ray collimation by crystals with precise parabolic holes based on diffractive-refractive 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 diffractive-refractive double-crystal 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 double-crystal set-up should provide tunable beam collimation within an energy range of 6.3-18.8 keV (Theta(B) = 71-18.4 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 three-dimensional (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 small-batch industrial experiments. The article describes the details of experimental setups, alignment procedures, and the underlying reconstruction principles. Imaging of interconnections in flip-chip and wire-bonded 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, In-line Bragg magnifier based on V-shaped germanium crystals, Journal of Synchrotron Radiation 18 753–760 (2011).
Reference here.

Abstract
In this work an X-ray imaging system based on a recently developed in-line two-dimensional Bragg magnifier composed of two monolithic V-shaped crystals made of dislocation-free germanium is presented. The channel-cut crystals were used in one-dimensional and in two-dimensional (crossed) configurations in imaging applications and allowed measurement of phase-contrast radiograms both in the edge-enhanced 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 one-dimensional configuration and 0.5 um in the two-dimensional 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 proof-of-principle experiment of a novel harmonics separation optics for synchrotron facilities, Journal of Synchrotron Radiation 19 1012–1014 (2012).
Reference here.

Abstract
A proof-of-principle 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 diffractive-refractive effect owing to the dispersive nature of X-ray refraction. A polychromatic beam containing higher-order energies is spatially separated behind the separator into individual monochromatic diffraction spots. A synchrotron experiment at a bending-magnet beamline with 7 keV fundamental energy is presented. The spot of the third-order 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 micro-computerized tomography imaging, Journal of Applied Crystallography 46 933–938 (2013).
Reference here.

Abstract
Free-space-propagation-based imaging belongs to several techniques for achieving phase contrast in the hard X-ray range. The basic precondition is to use an X-ray beam with a high degree of coherence. Although the best sources of coherent X-rays are synchrotrons, spatially coherent X-rays emitted from a sufficiently small spot of laboratory microfocus or sub-microfocus sources allow the transfer of some of the modern imaging techniques from synchrotrons to laboratories. Spatially coherent X-rays traverse a sample leading to a phase shift. Beam deflection induced by the local change of refractive index may be expressed as a dark-bright contrast on the edges of the object in an X-ray projection. This phenomenon of edge enhancement leads to an increase in spatial resolution of X-ray projections but may also lead to unpleasant artefacts in computerized tomography unless phase and absorption contributions are separated. The possibilities of processing X-ray images of lightweight objects containing phase contrast using phase-retrieval methods in laboratory conditions are tested and the results obtained are presented. For this purpose, simulated and recorded X-ray projections taken from a laboratory imaging system with a microfocus X-ray source and a high-resolution 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 channel-cut 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 V-shaped. 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 21-fold 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 channel-cut monochromator. The first attempt to overcome the mismatch by introducing different types of X-ray prisms for the required beam deflection is described as well. The performance of the V-shaped monochromators is demonstrated in two applications. A narrow collimated monochromatic beam obtained in the beam compressing mode was used for high-resolution grazing-incidence small-angle X-ray scattering measurements of a silicon sample with corrupted surface. In addition, a two-dimensional Bragg magnifier, based on two crossed V15 channel monochromators in beam expansion mode and tuned by means of unequal asymmetries, was successfully applied to high-resolution 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, Process-induced inhomogeneities in higher asymmetry angle X-ray monochromators, Proceedings SPIE Volume 8848: Advances in X-Ray/EUV Optics and Components VIII, edited by A. Khounsary, S. Goto, and C. Morawe, 88480U-1–88480U-8 (2013).
Reference here.

Abstract
Beam inhomogeneities of asymmetric Ge(220)-based V-shaped 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 V-channel monochromators observed in X-ray 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 V-channels, 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 X-ray crystal monochromators for advanced X-ay imaging applications, Proceedings SPIE Volume 9207: Advances in X-Ray/EUV Optics and Components IX, edited by C. Morawe, A. Khounsary, and S. Goto, 035101-1–035101-12 (2014).
Reference here.

Abstract
Advanced X-ray imaging techniques of weakly absorbing structures require an increase of the sensitivity to small refractive angles considering that they are based more on coherent X-ray phase contrast than on X-ray absorption one. Simulations of diffraction properties of germanium (Ge) X-ray crystal monochromators and of analyzer based imaging (ABI) method were performed for various asymmetry factors and several lattice plane orientations using an X-ray 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 X-ray 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, chemo-mechanical polishing and advanced nano-machining 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. Lawniczak-Jablonska, C. Mariani, P. Mikulik, J. Monnier, S. Morera, C. McGuinness, P. Müller-Buschbaum, 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 BIOSTRUCT-X 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 high-asymmetry angle x-ray crystal monochromators for advanced x-ray imaging and metrological applications, Optical Engineering 54 035101 (2015).
Reference here.

Abstract
We present the numerical optimization and the technological development progress of x-ray optics based on asymmetric germanium crystals. We show the results of several basic calculations of diffraction properties of germanium x-ray crystal monochromators and of an analyzer-based imaging method for various asymmetry factors using an x-ray 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 single-point 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 15-min 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 full-field X-ray 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, full-field X-ray microdiffraction imaging using synchrotron radiation is employed to investigate the long-range 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 high-flux X-ray beam compressing channel-cut monochromators, Journal of Applied Crystallography 49 1885–1892 (2016).
Reference here.

Abstract
The issue of a high-flux X-ray beam compressing channel-cut monochromator for applications in X-ray 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 single-point diamond technology (SPDT) to finish active surfaces of X-ray 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 high-flux X-ray compressors with a high compression ratio, where highly asymmetric diffraction with a very low exit angle is inevitable. The implications for efficient collection of X-rays from microfocus X-ray sources are discussed. A comparison of Ge compressors with Ge parallel channel-cut monochromators combined with a 50 µm slit shows the several times higher flux of the former, making them applicable in X-ray diffraction experiments at medium resolution. Furthermore, the Ge(111) compressor was tested as a collimator in high-resolution grazing-incidence small-angle X-ray 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