Epitaxial Si1–xGex/Si1–(x–y)Gex–y and Ge/SiyGe1–y layers were grown by UHV/CVD onto Si(100) substrates. It was surprisingly found that if the variation of the Ge composition, y, across the interface of Si1–xGex/Si1–(x–y)Gex–y or Ge/SiyGe1–y was higher than a certain value, most of the threading dislocations appear to be blocked and confined in the underlying Si1–(x–y)Gex–y or SiyGe1–y layer by the interface. It implied that this finding could provide a simple way to grow high-quality relaxed SiGe and Ge layers on the Si substrates.

Interface-Blocking Mechanism for Reduction of Threading Dislocations in SiGe and Ge Epitaxial Layers on Si(100) Substrates. T.H.Yang, G.L.Luo, E.Y.Chang, Y.C.Hsieh, C.Y.Chang: Journal of Vacuum Science & Technology B, 2004, 22[5], L17-9