FeRAM technology for high density applications

Ferroelectric random access memories (FeRAMs) are new types of memories especially suitable for mobile applications due to their unique properties like nonvolatility, small DRAM-like cell size, fast read and write as well as low voltage/low power behavior. Although standard CMOS processes can be used for frontend and backend/metallization processes, FeRAM technology development has to overcome major challenges due to new materials used for capacitor formation. In this paper, advantages and disadvantages of different ferroelectric materials and major development issues for high density applications are discussed. Results of a 0.5 μm ferroelectric process using SrBi 2Ta 2O 9 as ferroelectric layer, Pt as electrode material as well as two-layer tungsten/aluminum metallization are given as an example. Integration and reliability issues are reviewed.