A memory cell capacitor with Ba/sub x/Sr/sub 1-x/TiO/sub 3/ (BST) film for advanced DRAMs

The stored charges in the capacitor of the DRAM cell are decreased, as the power supply voltage and the memory cell area are reduced on the trend of the dimension shrinkage. To get sufficient capacitance of memory cell is one of the most important requirements for the advanced DRAMs. Therefore, a high-dielectric constant material has been proposed for memory cells of DRAM. It has been indicated that BST films realize the equivalent SiO2 thickness of 0.47 nm for the capacitor dielectric film of 256M DRAM. In this study, the process technology of the simple planar stacked cell with the BST film is developed. The memory cell capacitor with the high-dielectric constant BST film is applied to the fully functional 4M DRAM, in order to investigate the compatibility with the full DRAM fabrication process. The fabrication technology for the memory cell of DRAM with BST film capacitors and the DRAM performance are described.<>