A semiconductor structure includes a memory unit structure. The memory unit structure includes a transistor, a first electrode, two second electrode, and two resistive random access memory (RRAM) elements. The first electrode and the two second electrodes are disposed in a horizontal plane. The first electrode is disposed between the two second electrodes. The first electrode and the two second electrodes are disposed in parallel. The first electrode is coupled to a source region of the transistor. One of the two RRAM elements is disposed between the first electrode and one of the two second electrodes. The other one of the two RRAM elements is disposed between the first electrode and the other one of the two second electrodes.