Uniformity, Linearity, and Symmetry Enhancement in TiO<sub><i>x</i></sub>/MoS<sub>2-<i>x</i></sub>O<sub><i>x</i></sub> Based Analog RRAM via S-Vacancy Confined Nanofilament.

Sun, Dongdong; Zhu, Xudong; Chen, Shaochuan; Fang, Haotian; Zhu, Guixu; Lan, Gongpeng; He, Lixin; Shi, Yuanyuan · Nano Lett · 2024

basic_science · Level V

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Abstract

Due to the stochastic formation of conductive filaments (CFs), analog resistive random-access memory (RRAM) struggles to simultaneously achieve low variability, high linearity, and symmetry in conductance tuning, thus complicating on-chip training and limiting versatility of RRAM based computing-in-memory (CIM) chips. In this study, we present a simple and effective approach using monolayer (ML) MoS<sub>2</sub> as interlayer to control the CFs formation in TiO<sub><i>x</i></sub> switching layer. The limited S-vacancies (S<sub>v</sub>) in MoS<sub>2-<i>x</i></sub>O<sub><i>x</i></sub> interlayer can further confine the position, size, and quantity of CFs, resulting in a highly uniform and symmetrical switching behavior. The set and reset voltages (<i>V</i><sub>set</sub> and <i>V</i><sub>reset</sub>) in TiO<sub><i>x</i></sub>/MoS<sub>2-<i>x</i></sub>O<sub><i>x</i></sub> based RRAM are symmetric, with cycle-to-cycle variations of 1.28% and 1.7%, respectively. Moreover, high conductance tuning linearity and 64-level switching capabilities are achieved, which facilitate high accuracy (93.02%) on-chip training. This method mitigates the device nonidealities of analog RRAM through S<sub>v</sub> confined CFs, accelerating the development of RRAM based CIM chips.