Semiconductor device and method

Abstract

A method includes forming a multi-layer stack over a semiconductor substrate, the multi-layer stack comprising a plurality of sacrificial layers that alternate with a plurality of channel layers, forming a dummy gate stack over a top surface and sidewalls of the multi-layer stack, forming first spacers on sidewalls of the dummy gate stack, growing an epitaxial source/drain region that extends through the plurality of sacrificial layers and the plurality of channel layers, forming a metal-semiconductor alloy region on first portions of the epitaxial source/drain region, forming a coating layer on the metal-semiconductor alloy region, wherein during the forming of the metal-semiconductor alloy region and the coating layer, a residual layer is formed on sidewalls of the first spacers, and performing a wet clean process to selectively etch the residual layer from the sidewalls of the first spacers.