Solid-state reaction-mediated low-temperature bonding of GaAs and BnP wafers to Si substrates

We report a low-temperature wafer bonding method for the realization of integration of GaAsand InP-based optoelectronic devices with Si microelectronic devices. This method uses a Au-Ge eutectic alloy as the bonding material sandwiched between GaAs and Si wafers, and between InP and Si wafers. The bonding process was carried out at 280-300 “C by taking advantage of the low-temperature solid-state reactions occurring at GaAslAu-Ge, InP/Au-Ge, and Si/Au-Ge interfaces. Both the simple mechanical testand standard thermal cycling test prove excellent structural integrity of the joined wafers. Structural analyses reveal only limited interfacial reactions as well as solid-phase epitaxial regrowth of GeSi alloys on the Si substrate.