Hybrid-integrated GaAs/GaAs and InP/GaAs semiconductors through wafer bonding technology: Interface adhesion and mechanical strength

In this study, the interface adhesion and mechanical strength of wafer bonded GaAs/GaAs and GaAs/InP semiconductors, each of (100) face, were characterized by combining the measurements of interface fracture energy gamma(o) and lap shear strength E-s. The relations between the interface adhesion and annealing processes for four different types of bonding configurations, i.e., antiphase bonding, in-phase bonding, and twist bonding with 5degrees and 30degrees misalignments, were systematically studied. The surface free energy gamma(alpha-GaAs/oxide) (0.11-0.28 J/m(2)) of amorphous alpha-GaAs/oxide mixture was estimated based upon the reported surface free energy gamma(c-GaAs) (0.63 J/m(2)) of crystalline [100] GaAs and measured overall interface fracture energy gamma(total) (0.525 J/m(2)) of GaAs/GaAs bonded wafers. The micromorphologies of the bonded and debonded wafer interfaces were characterized by atomic force microscopy (AFM) and transmission electron microcopy (TEM). The interface microfailure mechanism of directly bonded GaAs wafers was proposed based on AFM and TEM microstructural analysis. (C) 2003 American Institute of Physics.