Germanium on insulator (GOI) structure locally grown on silicon using hetero epitaxial lateral overgrowth

A CMOS compatible technique for fabricating germanium (Ge) on insulator (GOI) structure that is locally implemented on silicon (Si) substrate is demonstrated. On a (100) crystalline Si substrate, silicon dioxide (SiO₂) is thermally grown. Then growth window for Ge is defined by locally etching down the SiO₂ to reveal the Si surface. Ge is grown epitaxially with multiple steps of high temperature hydrogen (H₂) annealing. After growing Ge crystals fill the growth window, the growth proceeds laterally and, finally coalesces with the neighbouring Ge growth window. Thus crystalline Ge sitting on SiO₂ is achieved. Chemical mechanical polishing (CMP) is used to planarize the surface, and wet etching is done to control the GOI film thickness.