A FINFET includes a substrate having a semiconductor fin extending upward from a first surface thereof, and first and second power rails on first and second opposing sides of the semiconductor fin, respectively. A base of the semiconductor fin may be recessed within a trench within the surface of the substrate, and the first and second power rails may at least partially fill the trench. A through-substrate via may be provided, which extends from adjacent a second surface of the substrate to at least one of the first and second power rails. A source/drain contact is also provided, which is electrically connected to a source/drain region of the FINFET and at least one of the first and second power rails.