A 64Mb SRAM in 22nm SOI technology featuring fine-granularity power gating and low-energy power-supply-partition techniques for 37% leakage reduction

A 64Mb SRAM is fabricated in a 22nm high-performance SOI technology [1]. The ever-increasing integration needs of complex SoC are driving the reduction of SRAM leakage power and increase in memory density. While the area and leakage power benefits of eDRAM continue to be leveraged in applications with large contiguous memory blocks [2], SRAM leakage remains a significant portion of the total SoC power. This work describes an SRAM that is optimized for leakage and performance as top priorities over density. The SRAM features a new bitcell (BC) implemented with a fine-granularity power-gating (FGPG) technique to reduce BC leakage by 37%. FGPG improves leakage reduction by 2× compared to bank-based power-gating (PG) techniques [3-4]. Periphery leakage is also reduced by 40% from the previous design [5] with a low-energy power-supply-partition design that leverages higher Vt devices operating at a higher supply voltage. This scheme alone provides an 8% improvement in performance with a small compromise to the AC power.