InP/Si heterogeneous integration by low-temperature bonding using metallic interlayer

A low-temperature InP/Si integration method using Au-Au surface-activated bonding (SAB) at a temperature of 150 °C was demonstrated for hermetic chip size packaging. Au sealing rings (thickness: 500 nm, width: 100 μm) and Au thin film (thickness: 300 nm) were used as bonding layers for SAB at atmospheric pressure. Fracture images after die shear test showed the interface area was well bonded and the fractures typically occurred inside the InP bulk chips. Helium leak rate was smaller than 1 × 10^-9 Pa·m³ s^-1. These results indicate that Au-Au SAB in an atmospheric pressure environment can be applied to high quality hermetic packaging of InP-based optoelectronic and high-speed devices.