A field effect transistor (FET) for an nFET and/or a pFET device including a substrate and a fin including at least one channel region decoupled from the substrate. The FET also includes a source electrode and a drain electrode on opposite sides of the fin, and a gate stack extending along a pair of sidewalls of the channel region of the fin. The gate stack includes a gate dielectric layer and a metal layer on the gate dielectric layer. The FET also includes an oxide separation region separating the channel region of the fin from the substrate. The oxide separation region includes a dielectric material that includes a portion of the gate dielectric layer of the gate stack. The oxide separation region extends completely from a surface of the channel region facing the substrate to a surface of the substrate facing the channel region.