Ferroelectric random access memories (FRAMS) having lower electrodes respectively self-aligned to node conductive layer patterns and methods of forming the same

摘要

A ferroelectric random access memory (FRAM) includes a semiconductor substrate and an interlayer insulating layer on the substrate. A diffusion preventive layer is on the interlayer insulating layer. The diffusion preventive layer and the interlayer insulating layer have two node contact holes formed therein. Node conductive layer patterns are aligned with the node contact holes, respectively, and are disposed so as to protrude upward from the diffusion preventive layer. Lower electrodes are disposed on the diffusion preventive layer that cover the node conductive layer patterns, respectively. Thicknesses of the lower electrodes are gradually reduced from a line extending from upper surfaces of the node conductive layer patterns toward the diffusion preventive layer.