An effective compliant substrate for low-dislocation relaxed Si 1-x Ge x growth

An effective compliant substrate for Si 1-x Ge x growth is presented. A silicon-on-insulator substrate was implanted with B and O forming 20 wt% borosilicate glass within the SiO 2 . The addition of the borosilicate glass to the buried oxide acted to reduce the viscosity at the growth temperature of Si 1-x Ge x , promoting the in situ elastic deformation of the thin Si (∼ 20 nm) layer on the insulator. The sharing of the misfit between the Si and the Si 1-x Ge x layers was observed and quantified by double-axis X-ray diffraction. In addition, the material quality was assessed using cross-sectional transmission electron microscopy, photoluminescence and etch pit density measurements. No misfit dislocations were observed in the partially relaxed 150-nm Si 0.75 Ge 0.25 sample as-grown on a 20% borosilicate glass substrate. The threading dislocation density was estimated at 2 x 10 4 cm -2 for 500-nm Si 0.75 Ge 0.25 grown on the 20% borosilicate glass substrate. This method may be used to prepare compliant substrates for the growth of low-dislocation relaxed SiGe layers.