Fabrication of strained Si on an ultrathin SiGe-on-insulator virtual substrate with a high-Ge fraction

A promising fabrication method for a ${\mathrm{Si}}_{\text{1−x}}{\mathrm{Ge}}_x$ -on-insulator (SGOI) virtual substrate and evaluation of strain in the Si layer on this SGOI substrate are presented. A 9-nm-thick SGOI layer with $\text{x=0.56}$ was formed by dry oxidation after epitaxial growth of ${\mathrm{Si}}_{\mathrm{0.92}}{\mathrm{Ge}}_{\mathrm{0.08}}$ on a silicon-on-insulator substrate. During the oxidation, Ge atoms were rejected from the surface oxide layer and condensed in the remaining SGOI layer, which was partially relaxed without introducing a significant amount of dislocations. It is found from the analysis of the Raman spectra that the strained Si layer grown on the SGOI layer involves a tensile strain of 1%. This strained Si on the SGOI structure is applicable to sub-100-nm metal–oxide–semiconductor field-effect transistors.