Dislocation engineering in SiGe on periodic and aperiodic Si(001) templates studied by fast scanning X-ray nanodiffraction

Fast-scanning X-ray nanodiffraction microscopy is used to directly visualize the misfit dislocation network in a SiGe film deposited on a pit-patterned Si substrate at the beginning of plastic relaxation. X-ray real-space diffracted intensity maps are compared to topographic atomic force microscopy images, in which crosshatch lines can be seen. The change in intensity distribution as a function of the incidence angle shows localized variations in strain within the SiGe film. These variations, which reflect the order imposed by the substrate pattern, are attributed to the presence of both bunches of misfit dislocations and defect-free regions. (C) 2014 AIP Publishing LLC.