Semiconductor devices and methods of manufacturing thereof

A semiconductor device, comprising:

• a fin structure disposed over a substrate, wherein the fin structure includes a plurality of semiconductor layers;
• a gate structure that comprises a lower portion and an upper portion, wherein the lower portion straddles the fin structure;
• a gate spacer that extends along a sidewall of the upper portion of the gate structure and comprises a vertical portion and tilted portion, wherein the vertical portion is in contact with the sidewall and the tilted portion overlays at least a first portion of a top surface of a topmost one of the plurality of semiconductor layers;
• and
• an etch stop layer extending between the tilted portion and a second portion of the top surface of the topmost semiconductor layer that is not overlaid by the tilted portion.

A semiconductor device, comprising:

• a plurality of semiconductor layers vertically separated from one another;
• a gate structure that comprises a lower portion and an upper portion, wherein the lower portion wraps around each of the plurality of semiconductor layers;
• a gate spacer that extends along a sidewall of the upper portion of the gate structure and has a bottom surface;
• wherein a portion of the bottom surface of the gate spacer and a top surface of a topmost one of the plurality of semiconductor layers form an angle that is less than 90 degrees;
• wherein the gate spacer comprises a plurality of dielectric layers;
• wherein at least one of the plurality of dielectric layers has a tilted portion that forms the bottom surface of the gate spacer;
• and
• wherein the tilted portion extends away from the sidewall of the upper portion of the gate structure.