RAPID VARIATION IN EPILAYER THREADING DISLOCATION DENSITY NEAR X = 0.4 IN GEXSI1-X ON (100) SI

A sharp increase in the number of dislocations threading from the heterointerface to the growth surface has been observed when the Ge content is increased (and consequently the critical thickness decreased) at about x=0.4 in GexSi1-x single epilayers grown on (100) Si. This increase by a factor of 60 times seems to be due to the change in glide behaviour of epithreading dislocations associated with interfacial misfit dislocations with thickness. The threading density difference persists in layers of equal thickness but differing Ge content to thicknesses well above critical. © 1990 Taylor & Francis Group, LLC.