X-RAY-ANALYSIS OF STRUCTURAL DEFECTS IN A SEMICONDUCTOR SUPERLATTICE

The structural defects in a (GaAs)m/(AlAs)n superlattice are studied experimentally and theoretically as well. Three models for the defects are proposed, which follow from the SL growth kinetics. Direct expressions for the reflectivities are derived from the semikinematical approximation of X-ray diffraction, assuming that the statistical parameters characterizing the defect models are distributed normally. On the basis of a numerical fit of the theoretical and experimental double crystal X-ray rocking curves the mean lattice parameter and the mean chemical composition as well as their statistical dispersions are found for a [(GaAs)m/(AlA)n]120 superlattice. The X-ray diffraction curves enable one to find the most probable model for the actual structural defects in the real superlattice.