2020 年 42 巻 3 号 p. 240-
Heterogeneous integration technologies that use wafer bonding are explained. The key points of several bonding methods are revealed, including direct bonding and resin bonding. Direct bonding enables tight strength at the interface without any glue, although maintaining a very fl at surface is crucial to achieve good bonding. Surface Activated Bonding, which is direct bonding method, achieved a low threshold current density of hybrid lasers. Resin bonding needs proper procure conditions before bonding to achieve a good interface without any voids. This bonding method creates a laser structure with a high index contrast to achieve an ultra-low threshold current of hybrid lasers.