Effect of dislocation density on integrated intensity of X-ray scattering by silicon crystals in Laue geometry

An investigation of integrated intensity is performed for reflections 111 and 333 in plane-polarized Cu Kα radiation for a series of silicon dislocation single crystals. Integrated intensity thickness oscillations (Pendellösung effect) have been found at low dislocation density (10-100 mm^-2). It is shown that the oscillations attenuate with increasing dislocation density, while their period somewhat increases. Thickness dependence of both extinction factor and polarization ratio is derived at high dislocation density (10³-10⁶ mm^-2). The present theoretical approaches based on the Darwin transfer equations appeared to be unsuitable for treating the obtained experimental data. They are analysed on the basis of coherent and diffuse scattering components.