Abstract: A semiconductor memory device includes a substrate having a cell array area and a core area near the cell array area, the cell array area including a direct contact hole exposing an active region, a buried contact in the cell array area, the buried contact being connected to a storage element, a direct contact in the cell array area, the direct contact including an upper layer and a lower layer, the upper layer including a metal, and the lower layer being in the direct contact hole in direct contact with the active region and including a silicide of the metal, bit lines in contact with the upper layer of the direct contact, and word lines crossing the bit lines.

Abstract: A semiconductor device including a first contact plug structure on a substrate, a lower spacer structure on a sidewall of the first contact plug structure, and a bit line structure on the first contact plug structure and including a conductive structure and an insulation structure stacked in a vertical direction substantially perpendicular to an upper surface of the substrate may be provided. The first contact plug structure may include a conductive pad contacting the upper surface of the substrate, an ohmic contact pattern on the conductive pad, and a conductive filling pattern on the ohmic contact pattern. The conductive filling pattern may include metal, and include a lower portion having a relatively large width and an upper portion having a relatively small width. The lower spacer structure may contact a sidewall of the conductive filling pattern.