A memory cell of a memory device is fabricated by forming a first electrode on a substrate, positioning a photo mask at a first position relative to the substrate, and forming a first material layer on the first electrode based on a pattern on the photo mask. The photo mask is positioned at a second position relative to the substrate, and a second material layer is formed above the first material layer based on the pattern on the photo mask, the second material layer being offset from the first material layer so that a first sub-cell of the memory cell includes the first material layer and not the second material layer, and a second sub-cell of the memory cell includes both the first and second material layers. A second electrode is formed above the first and second material layers.