Patent ID: 11948989
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  B | IPC H

Claim 13:
14. A method of forming a semiconductor device, comprising:
receiving a structure including a substrate and a stack of first semiconductor layers and second semiconductor layers alternately disposed over the substrate, wherein a topmost layer of the stack is one of the first semiconductor layers and includes a different material than the second semiconductor layers and the substrate;
forming a protective dielectric layer over the stack, wherein a bottom surface of the protective dielectric layer directly contacts a top surface of the topmost layer of the stack, wherein forming the protective dielectric layer includes:
depositing the protective dielectric layer over the topmost layer of the stack;
depositing a hard mask over the protective dielectric layer;
patterning the hard mask;
etching the protective dielectric layer and the stack using the hard mask as etch mask; and
removing the hard mask;

selectively removing the first semiconductor layers such that the second semiconductor layers and the protective dielectric layer are suspended over the substrate; and
after the selectively removing, forming a metal gate stack wrapping around the second semiconductor layers and the protective dielectric layer.