ReadMagin Enhanced PCSA for AOSFET 2TOC Gain Cell Memory

Short-channel-length thin-film amorphous oxide semiconductor field-effect transistor (AOSFET) two-transistor zero-capacitor (2TOC) gain cell (GC) memories are one of the promising technologies for three-dimensional integrated memories. 2TOC with a high-threshold voltage write transistor and a low-threshold voltage read transistor can achieve tens of thousands of seconds of retention time and low power consumption. However, the low threshold voltage of the read transistor leads to an increasing leakage current from the unselected data cells, which reduces the read margin. In this paper, we propose using a pre-charge sense amplifier (PCSA) to reduce leakage current and enhance the read margin. A reference generation circuit is also proposed to enhance the read accuracy. The simulation results show that the proposed PCSA increases the read margin to 168 mV. For the large array with 128 memory cells in a column, a 90 mV read margin can still be achieved compared to the 55 mV in the conventional SA setup.