A High-Density MOS Static RAM Cell Using the Lambda Bipolar Transistor

Based upon the common-collector lambda bipolar transistor (LBT), which is built with p-well NMOS, and the parasitic n-p-n BJT in a CMOS IC, a novel MOS static RAM cell called the LBT cell is proposed. In this new cell, the LBT and two poly-Si resistors form a bistable element with a PMOS access transistor. With the minimum feature size F, the optimal cell area of 32 F2 can be realized by using the silicide contact and small p-well spacing. The READ-WRITE operation is simulated. Due to the need of precharging before reading and the rather slow recovery after reading, suitable peripheral circuits should be designed.