US Patent 7427773 Layer transfer of low defect SiGe using an etch-back process

A method for forming strained Si or SiGe on relaxed SiGe on insulator (SGOI) or a SiGe on Si heterostructure is described incorporating growing epitaxial Si1−yGey layers on a semiconductor substrate, smoothing surfaces by Chemo-Mechanical Polishing, bonding two substrates together via thermal treatments and transferring the SiGe layer from one substrate to the other via highly selective etching using SiGe itself as the etch-stop. The transferred SiGe layer may have its upper surface smoothed by CMP for epitaxial deposition of relaxed Si1−yGey, and strained Si1−yGey depending upon composition, strained Si, strained SiC, strained Ge, strained GeC, and strained Si1−yGeyC or a heavily doped layer to make electrical contacts for the SiGe/Si heterojunction diodes.