Patent ID: 11961899
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H  B | IPC H

Claim 0:
1. A method for fabricating semiconductor devices, comprising:
forming a channel structure over a substrate, wherein the channel structure extends along a first lateral direction;
forming a gate structure extending along a second lateral direction and straddling a first portion of the channel structure;
forming a first gate spacer next to the gate structure, wherein the first gate spacer has a first lateral portion and a first vertical portion;
forming a second gate spacer over the first gate spacer, wherein the second gate spacer has a second lateral portion and a second vertical portion;
forming a third gate spacer over the second gate spacer, wherein the third gate spacer has a third lateral portion and a third vertical portion;
removing a second portion of the channel structure overlaid at least by the third lateral portion;
growing an epitaxial structure at least from a remaining portion of the channel structure; and
removing the second gate spacer to form an air gap, wherein the air gap is formed entirely above the epitaxial structure and vertically separated from the epitaxial structure by the first lateral portion of the first gate spacer.