Investigation of Si/Si bond interface fabricated using room temperature direct bonding

This study investigated the surface activation state of a Si wafer to achieve room-temperature bonding. The results obtained from direct Si/Si wafer bonding using surface-activated bonding (SAB) were compared with those obtained using the described room temperature bonding method with an activated Si atomic layer. Bond strength measurements and atomic-scale analysis of the bonded interfaces and debonded surfaces confirmed that the surface activation state of the few-nanometre-thick activated Si atomic layer was equivalent to that of the few-nanometre-thick Si amorphous layer formed by Ar fast atom beam irradiation. This result indicates that the room temperature bonding method performed using an activated Si atomic layer has the potential to achieve a sufficient bond strength with minimal damage, even in the case of oxide materials and compound semiconductors that are difficult to bond using the SAB method.