A High Performance Liquid-Nitrogen CMOS SRAM Technology

A 3.5 ns ECL-compatible 64Kb liquid-nitrogen CMOS (LN-CMOS) SRAM technology with 2.5V power-supply voltage is described. Key features of this high performance 0.5¿m-channel LN-CMOS SRAM technology optimized for 77K operation include 0.6,¿m optical lithography for the gate level, dual polysilicon work functions, retrograde n-well, low resistance arsenic and boron source/drain diffusions, self-aligned titanium silicide, and two-level metal interconnects. For the first time, the leverage of liquid nitrogen CMOS with 2.3X chip level performance improvement at 77K over room temperature CMOS is demonstrated.