Surface activated bonding of aluminum oxide films at room temperature

We have investigated the surface activated bonding (SAB) of deposited Al2O3 films by chemical vapor deposition under a short-time activated condition at room temperature. Although the surface energy for bonding of Al2O3 films was very low, that of Al2O3 film/sapphire bonding was approximately 1 J m − 2 and more than 2 J m − 2 for sapphire/sapphire bonding. Transmission electron microscopy showed an amorphous-like intermediate layer approximately 1 nm thick, observed at the bonding interface of Al2O3/Al2O3, but not in the bonding of Al2O3/sapphire, which suggests that the crystallinity of the Al2O3 film affects the bonding of Al2O3.