Low VMIN 20nm embedded SRAM with multi-voltage wordline control based read and write assist techniques

Measured results of VMIN from 20nm SRAM arrays with read and write assist techniques are presented for multiple flavors of bitcell. A novel assist technique is presented, that provides both read and write assist by controlling only the voltage of wordline (WL) and without using a separate supply voltage. The WL-drivers use a WL float technique to reduce the dc-path current compared to existing WL under-drive read assist designs. The assist technique resulted in a VMIN improvement of 143mV for the high-density 6T (6T-HD) SRAM, 96mV for the high-speed 6T (6T-HS) SRAM, and 86mV for the 8T dual-port (DP) SRAM.