Methods, devices and systems for a FinFET are provided. One method embodiment includes forming a FinFET by forming a relaxed silicon germanium (Si1-XGeX) body region for a fully depleted Fin field effect transistor (FinFET) having a body thickness of at least 10 nanometers (nm) for a process design rule of less than 25 nm. The method also includes forming a source and a drain on opposing ends of the body region, wherein the source and the drain are formed with halo ion implantation and forming a gate opposing the body region and separated therefrom by a gate dielectric.