SiGe virtual substrates growth up to 50% Ge concentration for Si/Ge dual channel epitaxy

We have grown in reduced pressure–chemical vapor deposition (RP-CVD) SiGe virtual substrates with Ge concentrations ranging from 20 up to 50%. We have observed an increase of the surface rms roughness with the final Ge content of the virtual substrates. Cross sectional transmission electron microscopy images revealed an effective confinement of the misfit dislocations inside the graded buffer. The final Ge content of the virtual substrate has no impact on the field threading dislocations density, whereas an increase of the pile-up threading dislocations density occurred. e then used Si0.49Ge0.51 virtual substrates as templates for the growth of Si/Ge dual channels. Although some dislocations were observed, mainly in the silicon layer, we have demonstrated the growth feasibility of such highly mismatched heterostructures in RP-CVD.