Fabrication of Hybrid Channel CFET Stack by Innovative Wafer-to-Wafer Bonding and Nanosheet Patterning
Student Contest:
No
Affiliation Type:
Research Facility
Keywords:
Complementary field effect transistor (CFET), wafer-to-wafer direct bonding, middle dielectric isolation (MDI), atomic diffusion bonding (ADB)
Abstract:
We have investigated the fabrication of complementary field-effect-transistor (CFET) stacks using wafer-to-wafer direct bonding. We demonstrate the successful fabrication and patterning of CFET stacks comprising a Si channel for nFET devices, a SiGe channel for pFET devices and a SiO2 middle dielectric isolation (MDI) layer. A defect-free 30 nm-thick SiN MDI is achieved through a combination of polishing-based surface preparation and direct bonding, highlighting the robustness of such an integration scheme. Furthermore, Atomic Diffusion Bonding (ADB) of SiO2-SiO2 and SiO2-Si interfaces is explored. Using this approach, a Si-SiO2-Si stack with ultra-thin SiO2 layer (5nm) is successfully fabricated, opening new perspectives for the integration of alternative MDI materials for next-generation CFET technologies.
