A semiconductor device includes a base substrate, a first electrode plate on the base substrate, a first power rail on the first electrode plate, the first power rail extending in a first horizontal direction and overlapping the first electrode plate in a vertical direction, a second power rail on the first electrode plate, the second power rail extending in the first horizontal direction and overlapping the first electrode plate in the vertical direction, and the second power rail being spaced apart from the first power rail in a second horizontal direction different from the first horizontal direction, a first power rail contact electrically connecting the first electrode plate and the first power rail, an insulating layer on the base substrate to surround the first electrode plate, the first power rail, and the second power rail, and a gate electrode extending in the second horizontal direction on the insulating layer.