Semiconductor structure and methods for manufacturing the same

Abstract

A method includes providing a substrate, forming a patterned hard mask layer over the substrate, etching the patterned hard mask layer to form a hole that penetrates the patterned hard mask layer, forming a barrier portion in the hole, removing the patterned hard mask layer, and forming a gate structure over the substrate. Formation of the gate structure includes forming a dielectric body portion on the substrate. The barrier portion that is thicker than the dielectric body portion adjoins one end of the dielectric body portion. The dielectric body portion and the barrier portion are collectively referred to as a gate dielectric layer. Formation of the gate structure further includes forming a gate electrode on the gate dielectric layer and forming gate spacers on opposite sidewalls of the gate electrode. During formation of the gate spacers, a portion of the barrier portion is removed to form a recessed corner.