High dose Ge+ ions were implanted into SIMOX substrates to synthesize SiGe alloys. These samples were evaluated by using RBS channeling and XTEM. The dose of implanted Get effects strongly the density of defects remaining in the surface SiGe layer. At a dose of 1.6??1016 Ge+ cm??2, SiGe layer with a very good crystallinity could be achieved through annealing at 950??C for 1h.