A plurality of magnetic tunnel junction structures is arranged in rows and columns on a substrate. A plurality of top electrodes is disposed on the plurality of magnetic tunnel junction structures, respectively. A plurality of bit lines is disposed on the substrate. One of the plurality of bit lines is disposed between two magnetic tunnel junction structures, adjacent to each other, of the plurality of magnetic tunnel junction structures. A top surface of each of the plurality of bit lines is disposed at substantially the same level as a top surface of each of the plurality of top electrodes.