US Patent 12132118 Semiconductor device having a multilayer source/drain region and methods of manufacture

Semiconductor devices and methods of fabricating the semiconductor devices are described herein. The method includes steps for patterning fins in a multilayer stack and forming an opening in a fin as an initial step in forming a source/drain region. The opening is formed into a parasitic channel region of the fin. Once the opening has been formed, a first semiconductor material is epitaxially grown at the bottom of the opening to a level over the top of the parasitic channel region. A second semiconductor material is epitaxially grown from the top of the first semiconductor material to fill and/or overfill the opening. The second semiconductor material is differently doped from the first semiconductor material. A stack of nanostructures is formed by removing sacrificial layers of the multilayer stack, the second semiconductor material being electrically coupled to the nanostructures.