A semiconductor device having a cell area and a peripheral area includes a semiconductor substrate, a cell insulating isolation region delimiting a cell active region of the semiconductor substrate in the cell area, a word line disposed within the semiconductor substrate in the cell area, a bit line contact plug disposed on the cell active region, a bit line disposed on the bit line contact plug, a peripheral insulating isolation region delimiting a peripheral active region of the semiconductor substrate in the peripheral area, and a peripheral transistor including a peripheral transistor lower electrode and a peripheral transistor upper electrode. The bit line contact plug is formed at the same level in the semiconductor device as the peripheral transistor lower electrode, and the bit line electrode is formed at the same level in the semiconductor device as the peripheral transistor upper electrode.