Strategic Material Design for Highly Reliable QLC 3D V-NAND Using Bypass Resistive Random Access Memory

• DOI: 10.1021/acsami.5c00352
• Publication Date: 2025-03-25T00:10:09Z
• Authors: Geonhui Han; Jongseon Seo; Junghoon Park; Minji Hong; Juhyung Kim; Kilho Lee; Wanki Kim; Daewon Ha; Hyunsang Hwang

To overcome the limitation of conventional flash memory, electrochemical random-access memory (ECRAM)-based bypass (bypass RRAM) has been proposed as a potential candidate for V-NAND application. While RRAM demonstrates excellent characteristics through ion hopping conduction, key parameters governing multilevel cell (MLC) operation remain unexplored. In this study, we propose design guidelines RRAM, targeting highly uniform quadruple-level (QLC) by using quantized oxygen vacancy (Vo) injections. achieve QLC operation, precisely controlled migration material engineering in RRAM. By leveraging unique electrical characteristic WOx resistive switching (RS) layer, minimized Vo (from WO2.65 to WO2.73), which enabled low-voltage (<5 V) and significant on/off ratio (>106) with minimal stoichiometry (Δx < 0.08) change. Additionally, parameters, such ionic barrier (Ea,ion) electrolyte layer diffusivity (Dion) RS were identified both high sensing margin based on MATLAB simulations experimental results. As result, optimized led superior performance, featuring distribution (σ/μ ∼ 0.01) (ΔG 4 μS) between each state without read disturbance issues. Finally, also confirmed that substantial reduction at nanometer scale suggests extending beyond levels injection, ensuring memory.