Multi-gate devices and fabricating the same with etch rate modulation

Abstract

The present disclosure provides a method of manufacturing a semiconductor device. The method includes forming a fin structure having first semiconductor layers and second semiconductor layers alternately stacked, forming a sacrificial gate structure over the fin structure, and etching a source/drain (S/D) region thereby forming an opening exposing at least one second semiconductor layer. The method also includes implanting an etch rate modifying species into the at least one second semiconductor layer though the opening thereby forming an implanted portion of the at least one second semiconductor layer. The method further includes selectively etching the implanted portion of the at least one second semiconductor layer, recessing end portions of the first semiconductor layers exposed in the opening, and forming an S/D epitaxial layer in the opening.