METHOD OF PREVENTING EPITAXY CREEPING UNDER THE SPACER

摘要

After forming a gate spacer on each sidewall of a sacrificial gate structure, portions of each dielectric fin cap portion underneath the gate spacer is intentionally etched and undercut regions that are formed are filled and pinched off with a dielectric material of a conformal dielectric liner. Portions of the conformal dielectric liner in the undercut regions are not subject to the undercut during an epitaxial pre-clean process performed prior to forming an epitaxial source region and an epitaxial drain region on opposite sides of the sacrificial gate structure and remain in the undercut regions after forming the epitaxial source region and the epitaxial drain region.

主权项

1. A semiconductor structure comprising:
a gate structure located on sidewall surfaces and a top surface of a channel portion of a fin structure; a dielectric liner portion located over the fin structure and laterally contacting a bottom portion of each sidewall of the gate structure; a gate spacer located over the dielectric liner portion and laterally contacting a remaining portion of each sidewall of the gate structure, wherein an outer sidewall of the gate spacer is vertically aligned with an outer sidewall of the gate dielectric liner portion; and an epitaxial source region and an epitaxial drain region adjacent the gate spacer and the dielectric liner portion, the epitaxial source region and the epitaxial drain region vertically contacting portions of the fin structure exposed by the gate structure, the gate spacer and the dielectric liner portion.