Uniformity, Linearity, and Symmetry Enhancement in TiO_<i>x</i>/MoS_2–<i>x</i>O_<i>x</i> Based Analog RRAM via S-Vacancy Confined Nanofilament

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) MoS₂ as interlayer to control the CFs formation in TiO_<i>x</i> switching layer. The limited S-vacancies (S_v) in MoS_2-<i>x</i>O_<i>x</i> 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>_set and <i>V</i>_reset) in TiO_<i>x</i>/MoS_2-<i>x</i>O_<i>x</i> 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_v confined CFs, accelerating the development of RRAM based CIM chips.