Center wordline cell: A new symmetric layout cell for 64 Mb SRAM

Abstract

A new symmetric memory cell, in which one wordline is placed at the center, has been developed for 64 Mb SRAM. This new center wordline cell has the benefits of a small cell size, good stability with operation voltages as low as 1.7 V, and suitability for implementation of phase shift lithography. A high performance TFT, which has on/off ratio of 7 orders even at 2.5 V operation, is mounted in this cell.<>