The structure of the interface defects of bonded Si/Si wafer pairs was investigated by means of high-resolution electron microscopy. Defects in the interface of bonded hydrophilic wafers appeared after annealing at 1100C. These were identified as being micro-twins. Bonded hydrophobic wafer pairs were characterized, after a similar annealing treatment, by the presence of a disturbed interface region which contained a large number of defects. In cross-sectional specimens, the defects were visible only at atomic dimensions and had a typical V-shaped formation parallel to {111} lattice planes. Simulations of high-resolution electron microscopic images revealed that they were probably stacking fault-like defects which were caused by the incorporation of self-interstitials.

M.Reiche, Q.Y.Tong, U.Gösele, J.Heydenreich: Materials Science Forum, 1995, 196-201 1847-52