Monolithic integration of III–V HEMT and Si-CMOS through TSV-less 3D wafer stacking

III-V compound semiconductor HEMT integrated with silicon CMOS on a silicon common substrate is promising to open up new circuit applications and capabilities. In the conventional hybrid approach, silicon and III-V circuits are fabricated and packaged separately, and then assembled on a carrier substrate. This approach is confronted by interconnect size and losses, which affect performance, form factor, power consumption, cost, and complexity. For III/V-Si hybrid integration, direct epitaxial growth of III-V compounds on Si substrate or CMOS devices would be the most desirable approach, but the high temperature III-V materials growth would severely degrade the CMOS transistors. 3D wafer stacking combining bonding and layer transfer, on the other hand, is another promising approach to integrate III-V materials on Si substrate. In this work, 3D wafer stacking is used to integrate III-V and silicon on a common platform to realize a novel side-by-side hybrid circuit without the need for through silicon via (TSV). Integration of III-V materials (InGaAs and GaN) and SOI-CMOS on a common 200 mm Si substrate is demonstrated. The SOI-CMOS layer is temporarily bonded on a Si handle wafer. Another III-V/Si substrate is then bonded to the SOI-CMOS containing handle wafer. Oxide to oxide bonding is used as a bonding medium in this case. Various oxide to oxide bonding combinations (e.g. thermal oxide bond to PECVD SiO2 and PECVD SiO2 bond to PECVD SiO2) will be discussed and the counter-measures will be implemented. Post-bonding annealing of the bonded wafer pair is carried out at 300 °C in an atmospheric N2 ambient for 3 hours to further enhance the bond strength to > 1200 mJ/cm2. Finally, a void free SOI-CMOS on III-V/Si hybrid structure on a common substrate can be realized after the handle wafer is released.