Low-temperature direct wafer bonding of GaAs/InP

An approach for low-temperature direct wafer bonding of GaAs/InP was presented. The bonding procedure was carried out at temperatures from 350 to 500 ∘C, and the bonded n-GaAs/n-InP specimens were obtained even at a temperature as low as 350 ∘C. The compositional profile on the GaAs/InP heterointerface was studied by X-ray photoelectron spectroscopy. The bonded interfacial properties were also characterized by current-voltage (I-V) and bonding strength measurement. The experimental results revealed an InGaAsP (or/and InGaAs) interlayer formed at the bonded interface, which influences the electrical property as well as the bonding strength. For the specimen bonded at 350 ∘C, the transport of major carriers could be explained by a tunneling effect. But the carrier transport was described by the thermionic emission theory for the specimen bonded at 450 ∘C. Finally, the mechanism of GaAs/InP bonding was discussed.