DETERMINING THE LATTICE-RELAXATION IN SEMICONDUCTOR LAYER SYSTEMS BY X-RAY-DIFFRACTION

This paper illustrates the procedure for extracting structural informa tion available from x-ray diffraction space mapping and topography. Th e methods of measuring, the residual strain, macroscopic tilts, micros copic tilts and their lateral dimensions, and the strain field disrupt ion emanating from the interfacial defects are presented. Partially re laxed thick InGaAs layers on GaAs substrates were studied and it was c oncluded that the relaxation and macroscopic tilting were anisotropic, the microscopic tilting reduced with thickness, and the interfacial d isruption did not continue to increase with increasing relaxation. A ' 'mosaic grain growth'' model is postulated to account for the diminish ing microscopic tilt spread and increasing topographic contrast with l ayer thickness.