A divided word-line structure in the static RAM and its application to a 64K full CMOS RAM

This paper describes a divided word-line (DWL) structure which solves inherent problems encountered in VLSI static RAMs. The key feature is to divide the word-line and to select it hierarchically with little area penalty using conventional process technology. In the application of the DWL structure, an 8K /spl times/ 8 full CMOS RAM has been developed with 2-/spl mu/m double polysilicon technology. The RAM has a typical access time of 60 ns. An operating current of 20 mA was obtained with a simple static design. The six-transistor cell configuration achieved a low standby current of less than 10 nA. For further improvement in speed, the second poly-Si layer was replaced with a polycide (poly-Si + MoSi/SUB 2/) layer, thus providing a 50-ns address access time.