59.
The region of the global minimum of the reliability factor is established for a 〈111〉 oriented Si crystal with thickness
z ranging within 200 <
z < 250 Å at an energy of
E = 100 keV. The value of this minimum allows one to perform structural analysis for a dynamically scattering specimen within the framework of the kinematical theory of diffraction. It is established that the formation of this region is provided by a small number of densely filled Bloch states. Theories of direct and back quasi-kinematical diffraction are developed. It is shown that the crystal under study can be brought into the region of quasi-kinematical diffraction by varying the accelerating voltage of the beam. The criteria are formulated that should be satisfied in this case.
相似文献