A reliable 1-Mbit DRAM with a multi-bit-test mode

A single 50V supply 1-Mb DRAM using a half V/SUB cc/ biased memory cell with a reduced electric field of 2 MV/cm and a shared sensing scheme for reasonable cell signal is described. A testability concept which allows 1/4 reduced test time, page/nibble functions including a continuous nibble mode, and an effective redundancy circuit are also described. A typical access time of 90 ns has been obtained using a titanium polycide world-line technology.