Chemical vapor deposition and electrode technologies for (Ba,Sr)TiO{sub}3 capacitor used in gigabit dram

摘要

We review our capacitor technology using (Ba,Sr)TiO{sub}3 (BST) as a capacitor dielectric for dynamic random access memory (DRAM) application. Among a number of issues for BST capacitor process integration in DRAM cells, two important technologies are discussed. As an electrode technology, we propose All PErovskite Capacitor (APEC) technology, in which conducting perovskite oxide of SrRuO{sub}3 (SRO) is used as capacitor electrodes. For chemical vapor deposition (CVD) of BST, we propose In-situ Multi-Step (IMS) process, which is a sequential repetition of low temperature deposition of ultra thin BST film and crystallization in the same chamber. By using APEC technology and IMS CVD process of BST, we can simultaneously achieve good electrical characteristics (low leakage current and high permittivity) and good step coverage. The combination of APEC technology and IMS CVD process of BST is a promising BST capacitor process technology for future DRAMs.