Optimization of FinFET-Based Gain Cells for Low Power Sub-V _T Embedded DRAMs

Sub-threshold circuits (sub-V _T) are a promising alternative in the implementation of low power electronics. The implementation of gain-cell embedded DRAMs (eDRAMs) based on FinFET devices requires a careful design to achieve the maximum cell performance (i.e., retention time, access time, and energy consumption) suitable for the sub-V _T operating level. In this work, we show that asymmetrically resizing the memory cell (i.e., the channel length of the write access transistor and the width of the rest of the devices) results in a 3.5× increase in retention time when compared to the nominal case while reducing area, as well. In terms of reliability (e.g., variability and soft errors), the resizing also improves the cell robustness (50% and 1.9×, respectively) when the cells are operated at sub-V _T level.