Continuous scaling of device dimension pushed CMOS technology based on Si materials to its physical limit, alternative high mobility channels such as (Si)Ge and III-V materials have been considered to replace Si to further enhance CMOS performance. In the meantime, ultrathin body (UTB) semiconductor-on-insulator is attractive for fabricating nanowire/nanosheet channel structures for improved gate controllability and immunity against short channel effects in the ultra-scaled high performance and low power dissipation CMOS. To realize multiple channels stacked semiconductor-on-insulator platform on current mainstream Si wafers, layer transfer technology utilizing direct bonding and selective etching was developed to integrate UTB (Si)Ge or InGaAs channels on Si. The devices fabricated with multiple stacked nanowire/nanosheet channels have also been demonstrated through sequential or monolithic 3D integration approach, showing great potential of layer transfer technology for ultimate CMOS structures.