(Ba,Sr)TiO/sub 3/ capacitor technology for Gbit-scale DRAMs

Great efforts have been made for the integration of high dielectric constant (Ba,Sr)TiO/sub 3/ (BST) capacitors into DRAMs. This paper presents the current state of the art in BST capacitor technology for Gbit-scale DRAMs, with emphasis on key technical issues for process integration, including electrode materials, barrier layers, and also BST films themselves. The problems which may remain to be solved are also discussed to realize the goal: a barrier layer on top electrode for back-end processes, reliability of integrated BST capacitors, and further improvement of coverage properties of BST films and cell-plate metals.