The Optimization of Program Operation for Low Power Consumption in 3D Ferroelectric (Fe)-NAND Flash Memory

Abstract

This paper proposes an optimized program operation method for ferroelectric NAND (FE-NAND) flash memory utilizing the gate-induced drain leakage (GIDL) program and validated through simulations. The program operation was performed by setting the time for the unselected cell to reach the pass voltage (Vpass) to 0.1 µs, 0.2 µs, and 0.3 µs, respectively. As the time for the unselected word line (WL) to reach Vpass increases, the channel potential increases due to a decrease in the electron–hole recombination rate. After the program operation, the threshold voltage (Vth) shift of the selected cell and the pass disturb of the unselected cells according to the Vpass condition were analyzed. Consequently, there was a more significant change in Vth among selected cells compared to the time for unselected cells to reach Vpass as 0.1 µs. The findings of this study suggest an optimal program operation that increases slowly and decreases rapidly through the variation of Vth according to the program operation. By performing the proposed program operation, we confirmed that low-power operation is achievable by reducing the WL voltage by 2 V and the bit line (BL) voltage by 1 V, in contrast to the conventional GIDL program.