Vertical Drive Device Polysilicon Load Static Random-Access Memory Cell
Original Publication Date: 1988-Dec-01
Included in the Prior Art Database: 2005-Feb-15
A method is shown for fabricating a 4-device (4D) n-channel static random-access memory cell (SRAM) with a combination of pass and drive devices that accommodate the need for a large drive device while offering a significant reduction in the planar dimensions over a 6D cell used in many high density SRAM product designs. (Image Omitted) In order to maintain cell stability in dense SRAM designs when replacing a 6D cell, utilizing a p-channel load device with a 4D n-channel cell, using a polysilicon load resistor, the cross coupled drive devices must be made substantially larger than the pass devices. This trade-off erodes much of the gain in area sought over the 6D design.