International Business Machines Corporation
Vertical stacked nanosheet CMOS transistors with different work function metals

Abstract:

A method for forming a semiconductor device includes forming a structure having at least a first nanosheet stack for a first device, a second nanosheet stack for a second device and disposed over the first nanosheet stack, a disposable gate structure, and a gate spacer. The disposable gate structure and sacrificial layers of the first and second nanosheet stacks are removed thereby forming a plurality of cavities. A conformal gate dielectric layer is formed in the plurality cavities and surrounding at least portions of the first and second nanosheet stacks. A first conformal work function layer is formed in contact with the gate dielectric layer. Portions of the first conformal work function layer are removed without using a mask from at least the second nanosheet stack. A second conformal work function layer is formed on exposed portions of the gate dielectric layer.