High Resolution X-Ray Diffraction in Multilayered Semiconductor Structures and Superlattices

X-ray diffraction patterns from layered structures yield detailed information on their structural parameters such as strain profile, chemical composition, layer thickness and interface quality. Any variation of the period, thickness of the individual layers, composition and homogeneity of the supelattics can be also determined. For an accurate determination of the structural properties a theoretical modeling of the experimental diffraction patters is, however, requird. The appropriate dynamical and kinematical models of x-ray scatting on multilayers are here reviewed and compared: The dynamical model gives only a rigotions description of the x-ray scattering. The unique capability of the x-ray diffraction technique to analyze multilayer structures is illustrated by investigations of the Al_xGa_1-xAs/GaAs and Ga_xIn_1-xAs/Al_yIn_1-y As material systems. X-ray scattering on periodic, quasiperiodic (Fibonacci superlattics), automatic (Theu-Morse superlattics), as well as on random systems is discussed.