engleski

2D GISAXS of nano-crystalline silicon thin films: analysis and modelling

Grazing-Incidence Small-Angle X-ray Scattering (GISAXS) spectra of nano-crystalline silicon thin films were simulated using freely available FORTRAN program IsGISAXS. Program calculates particles form factor in the distorted-wave Born approximation, which describes correctly the reflection-refraction effects at the substrate surface. In model calculations, the samples were assumed as mixture of random oriented nano-crystals and voids 2-30 nm in size, embedded in the amorphous matrix. The several particle shapes and size distributions were tested using, for initial values in calculation, the data estimated by HRTEM . The calculated spectra were compared with the measurements done on the Austrian SAXS line at the synchrotron Elettra (Trieste). By changing the initial values in calculation, the calculated spectra were fitted to the experimental values until reasonable match was obtained. In that way obtained individual particle sizes, size distribution and volume contribution each of element used in model calculation were compared with results of Raman and optical spectroscopy. GISAXS was performed at different incidence angles which allow the depth resolution and enables better comparison with other applied methods. The obtained results and usefulness of described procedure in analysis of thin films was discussed.

nano-crystalline silicon thin films; 2D GISAXS; modelling

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