Low temperature InP/Si wafer bonding

An oxide-free, covalently bonded interface of InP/silicon wafer pairs has been realized at low temperature by B2H6 plasma treatment of bonding surfaces in the reactive ion etch mode followed by a HF dip and room temperature bonding in air. The bonding energy reaches InP fracture surface energy of 630 mJ/m2 at 200 °C. A total B-doped amorphous layer of about 15 Å with peak concentration of ∼2×1020 cm−3 was detected at the bonding interface. The release of hydrogen at low temperature from B–H complexes and subsequent absorption of the atomic hydrogen by the amorphous layer at the bonding interface is most likely responsible for the enhanced bonding energy.