Application of synchrotron-radiation-based x-ray microprobe techniques for the analysis of recombination activity of metals precipitated at Si/SiGe misfit dislocations

In this study we report application of synchrotron-radiation-based x-ray microprobe techniques (the x-ray-beam-induced current (XBIC) and x-ray fluorescence (μ-XRF) methods) to the analysis of the recombination activity and space distribution of copper and iron in the vicinity of dislocations in silicon/silicon–germanium structures. A combination of these two techniques enables one to study the chemical nature of the defects and impurities and their recombination activity in situ and to map metal clusters with a micron-scale resolution. XRF analysis revealed that copper formed clearly distinguishable precipitates along the misfit dislocations. A proportional dependence between the XBIC contrast and the number of copper atoms in the precipitates was established. In hydrogen-passivated iron-contaminated samples we observed clusters of iron precipitates which had no recombination activity detectable by the XBIC technique as well as iron clusters which were not completely passivated.