Scanning x-ray microtopographs of misfit dislocations at SiGe/Si interfaces

Misfit dislocations at Si1-xGex/Si interfaces have been imaged by x-ray microdiffraction using the 004 diffraction peak of both the Si1-xGex layer and the Si(001) substrate. At the Si1-xGex layer peak, a decrease in the diffracted intensity is found at dislocations, with features as narrow as 4 μm. Similar features are seen using the Si peak; however, the diffracted intensity increases at the dislocations. We discuss the intensity contrast mechanisms and demonstrate that the distortion of the crystal lattice from the dislocations extends throughout the entire epitaxial layer structure. © 2001 American Institute of Physics.