Semiconductor memory device and method for fabricating the same

A semiconductor memory device comprises a substrate which includes a cell region, and a peri region defined around the cell region, the cell region including an active region defined by an element separation film, a storage pad connected to the active region of the cell region, a peri gate structure placed on the substrate of the peri region, a peri contact plug placed on both sides of the peri gate structure and connected to the substrate, a first interlayer insulating film which is placed on the storage pad and the pen contact plug, and includes a nitride-based insulating material, and an information storage unit connected to the storage pad, wherein a thickness of the first interlayer insulating film on an upper surface of the storage pad is smaller than a thickness of the first interlayer insulating film on an upper surface of the peri contact plug.