90NS 1MB DRAM WITH MULTI-BIT TEST MODE.

Summary form only given. A single 5-V, 1-Mb NMOS DRAM is described that uses reliable memory cells with a reduced electric field and a shared sensing scheme for a reasonable cell signal. A testability concept, a page-nibble function, including continuous nibble mode, and an effective redundancy circuit are included. The memory cell uses a half Vcc cell plate that reduces the electric field across the oxide of the memory capacity to 50% of that experienced with the conventional Vcc or Vss cell plate methods. A grounded epitaxial substrate is used to avoid the voltage bounce of the internally generated cell potential and minority carrier injection from the device inputs or peripheral circuits. The 35. 7- mu m**2 memory cell acts as a storage capacitance of 45 fF with 100-angstrom- thick oxide, while maintaining the electric field as low as 2 MV/cm.