A semiconductor device may include a substrate, a bitline extending in a first direction on the substrate, and an active pattern on the bitline. The semiconductor device may include a back gate electrode extending beside one side of the active pattern in a second direction perpendicular to the first direction across the bitline, and a wordline extending in the second direction beside the other side of the active pattern. A length of the active pattern in the second direction may be greater than a length of the bitline in the second direction.