US Patent 10367062 Co-integration of silicon and silicon-germanium channels for nanosheet devices

Nanosheet semiconductor devices and methods of forming the same include forming a first stack having layers of a first material and layers of a second material. A second stack is formed having layers of a third material, layers of the second material, and a liner formed around the layers of the third material. A dummy gate stack is formed over channel regions of the first and second stacks. A passivating insulator layer is deposited around the dummy gate stacks. The dummy gate stacks are etched away. The second material is etched away after etching away the dummy gate stacks. Gate stacks are formed over and around the layers of first and second channel material to form respective first and second semiconductor devices.