Abstract: A method includes forming an active region on a substrate, forming a sacrificial gate stack engaging the active region, measuring a gate length of the sacrificial gate stack at a height lower than a top surface of the active region, selecting an etching recipe based on the measured gate length of the sacrificial gate stack, etching the sacrificial gate stack with the etching recipe to form a gate trench, and forming a metal gate stack in the gate trench.

Abstract: Semiconductor structures and methods for manufacturing the same are provided. The method for manufacturing the semiconductor structure includes forming a fin structure protruding from a substrate, and the fin structure includes first semiconductor material layers and second semiconductor material layers alternately stacked. The method also includes forming a dummy gate structure across the fin structure and forming a gate spacer on a sidewall of the dummy gate structure. The method also includes partially oxidizing the gate spacer to form an oxide layer and removing the oxide layer to form a modified gate spacer. The method also includes removing the first semiconductor material layers to form gaps and forming a gate structure in the gaps to wrap around the second semiconductor material layers and over the second semiconductor material layers to cover the modified gate spacer.

Abstract: A method of controlling gate formation of a semiconductor device includes acquiring a correlation between gate critical dimensions (CDs) and etching recipes for forming gate trenches; measuring a gate CD on a target wafer; determining an etching recipe based on the correction and the measured gate CD; and performing an etching process on the target wafer to form a gate trench with the determined etching recipe.

Abstract: In an embodiment, a structure includes: a semiconductor substrate; a gate spacer over the semiconductor substrate, the gate spacer having an upper portion and a lower portion, a first width of the upper portion decreasing continually in a first direction extending away from a top surface of the semiconductor substrate, a second width of the lower portion being constant along the first direction; a gate stack extending along a first sidewall of the gate spacer and the top surface of the semiconductor substrate; and an epitaxial source/drain region adjacent a second sidewall of the gate spacer.

Abstract: A method of fabricating a device includes providing a fin having an epitaxial layer stack with a plurality of semiconductor channel layers interposed by a plurality of dummy layers. In some embodiments, the method further includes exposing lateral surfaces of the plurality of semiconductor channel layers and the plurality of dummy layers within a source/drain region of the semiconductor device. In some examples, the method further includes etching the exposed lateral surfaces of the plurality of dummy layers to form recesses and forming an inner spacer within each of the recesses, where the inner spacer includes a sidewall profile having a convex shape. In some cases, and after forming the inner spacer, the method further includes performing a sheet trim process to tune the sidewall profile of the inner spacer such that the convex shape of the sidewall profile becomes a substantially vertical sidewall surface after the sheet trim process.

Abstract: In an embodiment, a structure includes: a semiconductor substrate; a gate spacer over the semiconductor substrate, the gate spacer having an upper portion and a lower portion, a first width of the upper portion decreasing continually in a first direction extending away from a top surface of the semiconductor substrate, a second width of the lower portion being constant along the first direction; a gate stack extending along a first sidewall of the gate spacer and the top surface of the semiconductor substrate; and an epitaxial source/drain region adjacent a second sidewall of the gate spacer.

Abstract: In an embodiment, a structure includes: a semiconductor substrate; a gate spacer over the semiconductor substrate, the gate spacer having an upper portion and a lower portion, a first width of the upper portion decreasing continually in a first direction extending away from a top surface of the semiconductor substrate, a second width of the lower portion being constant along the first direction; a gate stack extending along a first sidewall of the gate spacer and the top surface of the semiconductor substrate; and an epitaxial source/drain region adjacent a second sidewall of the gate spacer.

Abstract: A method of controlling gate formation of a semiconductor device includes acquiring a correlation between gate critical dimensions (CDs) and etching recipes for forming gate trenches; measuring a gate CD on a target wafer; determining an etching recipe based on the correction and the measured gate CD; and performing an etching process on the target wafer to form a gate trench with the determined etching recipe.