(Ba,Sr)TiO3 thin films for ultra large scale dynamic random access memory.: A review on the process integration

Integration processes of the (Ba,Sr)TiO3 (BST) capacitors for the next-generation dynamic random access memories (DRAMs) are reviewed. Various integration schemes utilizing different processes, different electrode materials and structures are reviewed from the point of view of the mass-production compatible process. Integration issues, mostly related to the electrode and the barrier material and their fabrication techniques, are described. The current status and the problems of the two most viable techniques for the BST deposition, sputtering and metal-organic chemical vapor deposition (MOCVD), are comparatively described. Plate electrode technologies with the back-end processing issues are also briefly described, and some valuable experimental results are presented to show the feasibility of the BST capacitor.