Statistical analysis of minimum operation voltage (Vmin) in fully depleted silicon-on-thin-BOX (SOTB) SRAM cells

The minimum operation voltage (V_min) of fully depleted (FD) silicon-on-thin-BOX (SOTB) SRAM cells are measured and statistically analyzed. It is newly found that V_min deviates from a normal distribution and follows a log-normal distribution. Furthermore, it is found that the behaviors of the worst V_min are different from the median V_min or static noise margin (SNM), indicating that cell stability of high density SRAM must be judged by the worst V_min.