A semiconductor device and methods of manufacturing the same are provided. The semiconductor device includes a substrate, word lines, a doped junction, bit line structures, and buried contacts. The substrate has active regions. The word lines extend across the active regions. The doped junction has impurities and is arranged at the active regions, and includes first junctions and second junctions, each first junction arranged at a central portion of one of the active regions and each second junction arranged at an end portion of another one of the active regions, a buried semiconductor layer being included in each second junction. The bit line structures contact with a respective one of the first junctions. The buried contacts are arranged in a matrix shape, each contacting with a respective one of the second junctions and the included buried semiconductor layer and simultaneously contacting with a charge storage for storing data.