An experimental-analytical technique for the model-independent nondestructive characterization of single-crystal alloys is applied to partially strain-compensated SiGe:C/Si single layer structures with high concentrations of Ge. The studies were performed on pre- and postannealed SiGe:C/Si samples. X-ray Bragg diffraction profiles were collected at a synchrotron radiation source near the absorption edge of Ge. The studies have allowed the reconstruction of the complex crystal structure factor as a function of crystal depth, permitting direct observation of the effect of the thermal annealing on lattice strain and structural composition in the SiGe:C layer. The technique was shown to be applicable to the analysis of both perfect crystals and crystal structures containing a low defect concentration.