Characterization and Analyses of Interface Structures in Directly Bonded Si(011)/Si(001) Substrates

We investigated the interface structure of directly bonded Si(011)/Si(001) substrates prepared by conventional bonding and grind-back. The interfacial structure was analyzed by transmission electron microscopy (TEM) and in-plane X-ray diffraction (XRD). The plan-view and cross-sectional TEM observations provided evidence that screw dislocation lines were localized to the interfacial plane and that threading dislocations were absent. Grazing-incidence in-plane XRD analyses confirmed the existence of mosaic structures at the interface. These structures were formed because of the deformation field produced by the screw dislocations. This allowed a high level of crystallinity to be maintained in regions away from the interface in both the Si(011) layer and the Si(001) wafer.