TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Leitenberger, Wolfram
A1  - Vartanyants, Ivan A.
T1  - Coherence experiments at the EDR-beamline of BESSY II
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Leitenberger, Wolfram
A1  - Vartanyants, Ivan A.
T1  - Coherence experiments using white synchrotron radiation
N2  - Experiments at the bending magnet beamline at BESSY II (EDR beamline) profit from the excellent coherence properties of third generation synchrotron sources. Considering the exponentially decaying incident spectrum, and because no optical elements are installed except slits and vacuum windows, coherence experiments can be performed between 5 keV < E < 15 keV. First, the energy dependence of spatial coherence properties were determined measuring diffraction at single and double pinholes. Next, the coherent white radiation was used to probe the morphology of thin films in reflection geometry. The recorded intensity maps (reflectivity versus sample position) provide speckle patterns which reveal the locally varying sample morphology. Setting the incident angle, alpha(i), smaller or larger than the critical angle of total external reflection, alpha(c), one should be able to separate the surface height profile from the subsurface density modulation of a sample. The validity of this approach is verified at the example of reciprocal space maps taken from a polymer surface where we could reconstruct the lateral height profile from speckle data. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Pietsch, Ullrich
A1  - Panzner, Tobias
A1  - Pfeiffer, Franz
A1  - Robinson, Ian K.
T1  - Substrate morphology repetition in "thick" polymer films
N2  - Using Grazing-incidence small-angle scattering (GISAXS) technique we investigated the surface morphology of polymer films spin-coated on different silicon substrates. As substrates we used either technologically smooth silicon wafers or the same silicon wafer coated with thin aluminium or gold films which show a granular structure at the surface. Although the polymer thickness exceeds 300 nm the GISAXS pattern of the film shows the same in-plane angle distribution Delta2theta as the underlying substrate. Annealing the polymer films at a temperature above its glass transition temperature Delta2theta changed from a broad to a narrow distribution as it is typically for films on pure silicon. The experiment can be interpreted by roughness replication and density fluctuation within the polymer film created while spin-coating at room temperature. Due to the low segment mobility there are density fluctuations which repeat the surface morphology of the substrate. Above the glass temperature the polymer density can be homogenized independently from the morphology of the substrate. (C) 2004 Elsevier B.V. All rights reserved
Y1  - 2005
ER  -