Bipolar CMOS-merged technology for a high-speed 1-Mbit DRAM

A novel high-performance bipolar-CMOS (complementary metal oxide semiconductor) merged technology for a 1-Mb DRAM (dynamic random access memory) is proposed. A memory cell having a twenty-times-higher soft-error immunity (as compared to the conventional device) in its bit-line mode and a bipolar transistor having a high-drive ability (f/sub T/=5.2 GHz at I/sub c/=1.2 mA) can be realized. The fabrication process is fully compatible with the conventional CMOS DRAM and involves only three additional masking steps. An experimental 1-Mb BiCMOS (bipolar CMOS) DRAM was fabricated using this technology, with a typical access time of 32 ns.>