Nucleation of dislocations in SiGe layers

We present an x-ray diffraction study of the variation of the tilt angle between a relaxed Si1-xGex epitaxial layer and the Si (001) substrate. Such measurements provide the basis for a new method to determine the nucleation activation energy of misfit dislocations. We show that the nucleation activation energy for 060° dislocations in the case of the multiplication mechanism observed in graded SiGe layers from by UHV-CVD at low temperature is 4 eV.