A study was made of the crystallographic structure of interfaces which were obtained by wafer-fusion using various procedures. Plan-view and cross-sectional transmission electron microscopy revealed that the interface was not composed only of a regular array of 2 sets of edge dislocations, and was more complex than was generally supposed. If a twist was created, due to misalignment of the 2 substrates, the dislocations were not of pure edge-type, but also had a screw component. Dislocations for which the Burgers vector had a component normal to the interface were also present. Those dislocations were thought to result from steps, and some of them accommodated the tilt between the 2 substrates. Inclusions and voids, as well as a low number of bulk dislocations were present in all of the samples. The observed bulk dislocation density near to the interface was in the range of 105 to 107/cm2, and these dislocations were attributed to the effect of thermal mismatch.

Defects, Structure, and Chemistry of InP-GaAs Interfaces Obtained by Wafer Bonding L.Sagalowicz, A.Rudra, E.Kapon, M.Hammar, F.Salomonsson, A.Black, P.H.Jouneau, T.Wipijewski: Journal of Applied Physics, 2000, 87[9], 4135-46