A semiconductor device includes a semiconductor substrate, a gate structure, a source region, a drain region, an interconnect structure, a memory cell and a conductive via. The semiconductor substrate has a first side and a second side opposite to the first side. The gate structure is disposed over the first side of the semiconductor substrate. The source region and the drain region are disposed in the semiconductor substrate aside the gate structure. The interconnect structure is disposed over the first side of the semiconductor substrate and electrically connected to the source region. The memory cell is disposed over the second side of the semiconductor substrate and electrically connected to the drain region. The conductive via is disposed in the semiconductor substrate between the drain region and the memory cell and electrically connects the drain region and the memory cell.