The present application discloses a semiconductor device and a method for fabricating the semiconductor device. The semiconductor device includes a first dielectric layer on a substrate; first/second upper short axis portions extending along a first direction, separated from each other, and on the first dielectric layer; a common source region in the substrate and adjacent to the first/second upper short axis portions; a first branch drain region in the substrate, adjacent to the first upper short axis portion, and opposite to the common source region; a second branch drain region in the substrate, adjacent to the second upper short axis portion, and opposite to the common source region; and a top electrode on the first dielectric layer and topographically above the first branch drain region and the second branch drain region. The top electrode, the first dielectric layer, and the first/second branch drain regions together configure a programmable unit.