Single polysilicon cross-coupled resistor, six-transistor SRAM cell design technique

摘要

A six-transistor latch cell is formed with resistors connecting opposite nodes of the latch. A Salicide (self-aligned silicide) isolation mask layer (25) is used to permit the use of a single layer of polysilicon (23) to implant both the two resistors and the six transistors. The Salicide isolation mask (25) is provided to mask all high energy dopant implants in the poly resistor region and to function as a dielectric between the poly resistor and the local interconnect (27) passing above it. This Salicide isolation layer (25) is easy to manufacture, and adds very little to the vertical topology.