Progress in the developments of (Ba,Sr)TiO3 (BST) thin films for Gigabit era DRAMs

This paper reviews the recent developments of (Ba,Sr)TiO3 (BST) thin films for future Gbit era dynamic random access memory (DRAM) applications. The t rends of DRAM capacitors in the last decade are briefly described first. Th en the technological aspects of BST films such as deposition techniques, po st-annealing, physical, electrical and dielectric characteristics of the fi lms, effects of electrode materials, dielectric relaxation and defect analy sis and the reliability phenomena associated with the films are briefly rev iewed with specific examples from recent literature. The basic mechanisms t hat control the bulk electrical conduction and the origin of leakage curren ts in BST films are also discussed. Finally, possible developments of gigab it era DRAM technology are summarized. (C) 2000 Elsevier Science S.A. All r ights reserved.