Interface structure and adhesion of wafer-bonded GaN/GaN and GaN/AlGaN semiconductors

Material integrations of GaN/GaN and Al0.25Ga0.75N/GaN semiconductors through wafer bonding technology were reported in this work. The wafer surface and interface microstructures were characterized by scanning electron microscopy and energy dispersive x-ray spectroscopy. The interface adhesion (bonding strength) was estimated based upon the interface fracture energy gamma(o) measured by double-cantilever beam technique. The interface adhesion properties of several different wafer-bonded III-V semiconductors were also compared. By comparing the atomic chemical bond energy E-o with the measured interface fracture energy gamma(o), the bondability of a few major III-V semiconductors was analyzed. (C) 2004 American Institute of Physics.