Exact determination of superlattice structures by small-angle x-ray diffraction method

Abstract

The structure of In1-xGaxAsyP 1-y/InP superlattices (x=0.27 and y=0.60) is investigated by small-angle x-ray diffraction method. The interference peaks due to the superlattice structure were clearly observed up to the 6th order. The period of the superlattice was determined from the angular positions of the peaks using the modified Bragg's law. By analyzing the diffraction patterns of the first and the secondary peaks according to the optical multilayer theory, the thickness of each component (In1-xGaxAsyP1-y and InP) was uniquely determined within an error of ±1 Å. This method can be used to determine any type of superlattice structure.