The design and performance of CMOS 256K bit DRAM devices

The design and performance of CMOS 256K bit dynamic random access memory devices with 256K×1 and 64K×4 output configurations are presented. An advanced CMOS technology, with device scaling to the HMOS-III level, is used to provide effective solutions to critical device and circuit problems in DRAM design and to offer features not previously implemented in NMOS designs. The cell and die area are 70 μm/SUP 2/ and 253 mil □ (6.3 mm □), respectively. The typical row access time is less than 100 ns. The p-channel memory array used in this design improves the memory refresh characteristics and reduces the soft error rates. The use of static and clocked CMOS circuits provides lower active power, wide operating margins, microwatt standby power, and high column data bandwidth. The 256K bit devices are designed with two output modes, namely, ripplemode and static column mode, selected by a metal mask option.