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

Misfit dislocations at Si1-xGex/Si interfaces have been imaged by x-ray mic rodiffraction 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 diffr acted intensity is found at dislocations, with features as narrow as 4 mum. Similar features are seen using the Si peak; however, the diffracted inten sity increases at the dislocations. We discuss the intensity contrast mecha nisms and demonstrate that the distortion of the crystal lattice from the d islocations extends throughout the entire epitaxial layer structure. (C) 20 01 American Institute of Physics.