Dislocation strain field in ultrathin bonded silicon wafers studied by grazing incidence x-ray diffraction -: art. no. 165337

An ultrathin silicon layer (16 nm) bonded onto a silicon wafer is studied by grazing incidence x-ray diffraction. We measure satellite peaks around the {220} reflections coming from two periodic dislocation networks localized at the bonding interface. These lateral superlattice peaks are explained with a simple continuum model, and their positions give information about the tilt and twist misalignment of the two crystals, as well as the nature and interactions between the dislocation arrays. The square symmetry of dissociated screw dislocations (twist) and the average alignment of the mixed dislocations (tilt) are observed. The analysis of the satellite truncation rods shows that the strain field is strong enough to affect the surface, and that the dissociation of screw dislocations has to be taken into account.