US Patent 9818872 Multi-gate device and method of fabrication thereof

A method of semiconductor device fabrication is described that includes forming a fin extending from a substrate and having a source/drain region and a channel region. The fin includes a first epitaxial layer having a first composition and a second epitaxial layer on the first epitaxial layer, the second epitaxial layer having a second composition. The second epitaxial layer is removed from the source/drain region of the fin to form a gap. The gap is filled with a dielectric material. Another epitaxial material is formed on at least two surfaces of the first epitaxial layer to form a source/drain feature.