| The double-crystal x-ray diffraction simulation technology and kinematics theory simuation of DXRD rocking curve are the effective ways of studying semiconductor superlattice"s structure and perfection. In this paper. X-ray rocking curve theoretical simulation iterative solutions were obtained for the multi-layer and superlattice structures.We have conducted detailed analyses on the structure parameters and perfection of several muti-layer films and superattices.1. The AlGaAs/AlGaAs superlattice and quantum well structure parameters have been calculated, and the extinction rule of lower satellite peaks has been studied. Adopting the Integer Molecular Layer Transition Layer theoretical model, we have studied the peak location excursion of superlattice's zero order peak, and transition layer effect on the superlattice's satellite peaks intensity.2. We have carried out detailed study on the relaxation mechanisms and structure parameters of InGaAs/GaAs epitaxial multi-layer structures. Based on the experimental analysis of 15 period In0.1Ga0.9As/GaAs superlattice ,we arrived at the conclusion that the strain relaxation mechanism is the principle mechanism. Through simulation calculation, we have successfully obtained the superlattice parameters for the sample, they are respectively: period 200A|°, In content 0.08, thickness tGaAs 110A|°, and tAlGaAs 90A|°.3. We have designed and grown GaSb/GaAs samples with different structure parameters, optimized the growth conditions and parameters. In our XRD experiments of GaSb/GaAs strained superlattice we have successfully observed satellite peaks up to the 7th order. We conducted the theoretical fitting optimization with experimental results based on the effects on growth temperature and composition change on the epilayer quality, and detailed analysis of the effects of buffer layer thickness and growth rate on XRD results. Analysis and discussion have been given to the factors affecting the imperfection of GaSb/GaAs strained superlattice. |
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