Low-Temperature Fabrication of Germanium-on-Insulator Using Remote Plasma Activation Bonding and Hydrogen Exfoliation

Low-temperature germanium to silicon wafer bonding was demonstrated by in situ radical activation and bonding in vacuum. After low temperature direct bonding of Ge to Si followed by annealing at 200 and 300 C, advanced imaging techniques were used to characterize the bonded interface. The feasibility of transferring hydrogen-implanted germanium to silicon with a reduced thermal budget is also demonstrated. Germanium samples were implanted with hydrogen and a two-step anneal was performed. The first anneal performed at low temperature (B150 C for 22 h) to enhance the nucleation of hydrogen platelets. The second anneal is performed at 300 C for 5 min and is shown to complete the exfoliation process by triggering the formation of extended platelets.