Low-Temperature Material Stacking of Ultrathin Body Ge (110)-on-Insulator Structure via Wafer Bonding and Epitaxial Liftoff From III-V Templates

Abstract

In this brief, we fabricated Ge (110)-on-insulator (-OI) structures on Si substrates viawafer bonding and epitaxial lift-off (ELO) process using Ge layer grown on GaAs for low-temperature layer stacking toward monolithic 3-D integration. We also systematically investigated the lateral etching behaviors of AlAs, which was used as a sacrificial layer in the ELO process, on GaAs (110) substrates. Fabricated Ge (110)-OI was analyzed by surface atomic force microscopy, X-ray diffraction, Raman shift, and transmission electron microscope analyses. We found that the 40-nm-thick ultrathin-body Ge (110)-OI has very high crystal quality, indicating our Ge stacking process is very stable.