A semiconductor device may include, but is not limited to: a semiconductor substrate; a bit line; and a contact portion. The semiconductor substrate has a first groove having at least first and second side surfaces facing each other. The bit line is positioned in the first groove. The bit line is insulated from the semiconductor substrate. The contact portion is positioned in the first groove. The contact portion is electrically connected to the bit line. The contact portion contacts the first side surface of the first groove. The contact portion is insulated from the second side surface of the first groove.