A memory device includes a semiconductor device on a wafer. The semiconductor device includes a gate structure, a first source/drain region, and a second source/drain region. The gate structure is on the first side of the wafer. The first source/drain region is also on the first side of the wafer, and contacts a first end of the gate structure. The second source/drain region is on the second side of the wafer and extends into the first side to contact a second end of the gate structure. The memory device further includes a memory storage element on the second side of the wafer. The memory storage element contacts the second source/drain region.