Fabrication of Germanium-on-Insulator by low temperature direct wafer bonding

A Germanium-on-Insulator (GeOI) wafer was fabricated using low temperature direct wafer bonding method. A hydrogen implanted Ge donor wafer was bonded to a thermally oxided Si handle wafer with in-situ oxygen radical activation before bonding in a vacuum chamber. Ex-situ anneals were use to enhance the bond strength or exfoliate the implanted Ge wafer. The insight into the exfoliation mechanism of the hydrogen implanted Ge wafer was observed by the surface roughness and x-ray diffraction pattern (XRD) measurements, combined with the high resolution transmission electron microscopy (HRTEM). The Ge surface after radical activation was analyzed by angle-resolved x-ray photoelectron spectroscopy (ARXPS). Scanning electron microscopy (SEM) was used to characterize the exfoliated Ge surface on handle SiO₂ film.