Patent ID: 7713837

Claim:
A method of bonding two wafers having a bonded surface area comprising: providing a first wafer having a substantially out-gassed oxide layer formed on a surface thereof, said oxide layer being formed at a temperature T 1 ; providing a second wafer having a surface; treating the substantially out-gassed oxide layer of the first wafer and the surface of the second wafer with a solution containing NH 4 OH; contacting the treated surfaces with each other; and annealing the two wafers at a temperature T 2 which is less than or equal to T 1 thereby forming a bonded wafer pair which has a surface energy of about 2000 mJ/m 2 or greater and a bonded interface that has a dislocation density of less than 10 6 cm −2 and a void/bubble density of less than about 1% of the bonded surface area.