Methods for forming source/drain features

Abstract

A semiconductor structure and a method of forming the same are provided. In an embodiment, a method includes receiving a workpiece comprising a substrate, an active region protruding from the substrate, and a dummy gate structure disposed over a channel region of the active region. The method also includes forming a trench in a source/drain region of the active region, forming a sacrificial structure in the trench, conformally depositing a dielectric film over the workpiece, performing a first etching process to etch back the dielectric film to form fin sidewall (FSW) spacers extending along sidewalls of the sacrificial structure, performing a second etching process to remove the sacrificial structure to expose the trench, forming an epitaxial source/drain feature in the trench such that a portion of the epitaxial source/drain feature being sandwiched by the FSW spacers, and replacing the dummy gate structure with a gate stack.