Low-Defect-Density Ge Epitaxy on Si(001) Using Aspect Ratio Trapping and Epitaxial Lateral Overgrowth

Low-defect-density Ge epitaxy was fabricated using aspect ratio trapping combined with epitaxial lateral overgrowth techniques. Dislocations from the Ge/Si interface were trapped inside oxide trenches, and then Ge was laterally grown to form 20 mu m wide, 6 mm long strips. Chemical mechanical polishing of Ge was used to planarize the faceted strips. Uncoalesced Ge strips showed a defect density as low as 1.6x10(6) cm(-2) from plan-view transmission electron microscopy, while coalesced Ge had higher defect density. This approach shows great promise for the integration of low-defect-density Ge and III-V materials on Si.