Energy-Dispersive Synchrotron Radiation Topographic Observation of InAs/GaAs Lattice-Mismatched Layer

Using white synchrotron radiation X-ray scattering spectrotopographic observation of InAs lattice-mismatched heteroepitaxial layer on GaAs substrate is described. Due to a considerable discrepancy between the lattice constants of InAs and GaAs, we took four topographs of the (002) and (004) InAs epitaxial layer, and of the (002) and (004) GaAs substrate, simultaneously. In order to discuss the defect contrast in detail, we made computer simulation of this experiment as a white beam topography using the Takagi-Taupin equations. Concerning the contrast from a local displacement from the matrix including a strain field, the behavior of white beam topographs is different from that of monochromatic ones.