US Patent 9660033 Multi-gate device and method of fabrication thereof

A method of semiconductor device fabrication includes providing a fin extending from a substrate and having a source/drain region and a channel region. The fin includes a first layer, a second layer over the first layer, and a third layer over the second layer. A gap is formed by removing at least a portion of the second layer from the channel region. A first material is formed in the channel region to form first and second interfacial layer portions, each at least partially wrapping around the first and third layers respectively. A second material is deposited in the channel region to form first and second high-k dielectric layer portions, each at least partially wrapping around the first and second interfacial layer portions. A metal layer including a scavenging material is formed along opposing sidewalls of the first and second high-k dielectric layer portions in the channel region.