Semiconductor device and methods of forming the same

Abstract

In an embodiment, a method includes: forming a plurality of semiconductor layers over a substrate, the plurality of semiconductor layers comprising alternating first semiconductor layers and second semiconductor layers; patterning the plurality of the semiconductor layers into a fin; etching the fin to form a first recess; forming an epitaxial region in the first recess, forming the epitaxial region comprising: forming first epitaxial layers over sidewalls of the second semiconductor layers; forming second epitaxial layers over the first epitaxial layers; forming shape fixing layers over the second epitaxial layers; and forming a bulk epitaxial layer over the shape fixing layers. The method further includes removing the first semiconductor layers to form a second recess between the second semiconductor layers; and forming a gate structure in the second recess.