Relaxed silicon–germanium-on-insulator substrates by oxygen implantation into pseudomorphic silicon germanium/silicon heterostructure

We have developed a modified separation-by-implantation-of-oxygen (SIMOX) process for fabricating relaxed silicon–germanium-on-insulator (SGOI) substrates without using thick graded SiGe buffer structures. Oxygen ions are implanted into a pseudomorphically grown 115 nm Si0.86Ge0.14 layer, with the implant peak located slightly below the heterostructure interface. Following two annealing processes (∼800+1350 °C) instead of conventional one-step annealing (∼1350 °C) in traditional SIMOX, a buried silicon dioxide layer is created near the original SiGe/Si interface, resulting in a fully relaxed SGOI structure. Our results show that an annealing step at a moderate temperature (∼800 °C) leads to less Ge loss.