Reduction of dislocation density in mismatched SiGe/Si using a low-temperature Si buffer layer

The reduction of the dislocation density in relaxed SiGe/Si heterostructures using a low-temperature Si(LT-Si) buffer has been investigated. We have shown that a 0.1 μm LT-Si buffer reduces the threading dislocation density in mismatched ${\mathrm{Si}}_{\mathrm{0.85}}{\mathrm{Ge}}_{\mathrm{0.15}}\mathrm{/Si}$ epitaxial layers as low as ${\text{∼10}}^4\hspace{0.17em}{\mathrm{cm}}^{\mathrm{-2}}.$ Samples were grown by both gas-source molecular beam epitaxy and ultrahigh vacuum chemical vapor deposition.