Multi-Gate Devices and Fabricating the Same with Etch Rate Modulation

The present disclosure provides a semiconductor device and a method of manufacturing the semiconductor device. The semiconductor device includes channel members disposed over a substrate, a gate structure engaging the channel members, and an epitaxial feature adjacent the channel members. At least one of the channel members has an end portion in physical contact with an outer portion of the epitaxial feature. The end portion of the at least one of the channel members includes a first dopant of a first concentration. The outer portion of the epitaxial feature includes a second dopant of a second concentration. The first concentration is higher than the second concentration.