US Patent 10084094 Wrapped source/drain contacts with enhanced area

Semiconductor device and methods of forming the same include forming a first dielectric layer over a semiconductor fin. A second dielectric layer is formed around the first dielectric layer. The semiconductor fin is recessed below a height of the first and second dielectric layers. Source and drain extensions are grown from the recessed semiconductor fin. The first dielectric layer is recessed to expose an underside of and sidewalls of the source/drain extensions. Conductive contacts are formed around exposed portions of the source/drain extensions.