Novel Back Gate Doping Ultra Low Retention Power 22nm FDSOl SRAM for IOT Application

This paper presents a 0.110um ² Ultra Low Leakage (ULL) 6T-SRAM for Internet Of Things (lOT) application with competitive 0.7pA/cell retention leakage and $\pmb{1.45}\mathbf{mV}^{\ast}\mathbf{um}$ transistor mismatch coefficient (AVT). A back gate doping method to control the sub-threshold leakage is demonstrated on 22FDX™ (a 22nm FDSOI technology), which increases VT while maintaining the same AVT as compared to the case with no back gate doping. We demonstrate extremely low retention voltage (Vret) capability down to 0.35V on a 32Mb SRAM array with a corresponding SRAM VDD domain retention leakage of 0.9uA/Mb at 0.5V.