Reset Variability in Backfilled Resistive Random Access Memory and Its Correlation to Low Frequency Noise in Read

Abstract

Fast and stable switching between states is one of the key factors for the success resistive random access memory (RRAM) development. In an array, wide reset efficiency variation in RRAM cells is found to link to the characteristics of its low frequency noise (LFN) in bit-cell current. Through Monte Carlo simulation on randomly placing conductive filaments (CF), LFN characteristics correspond to the densities of the CF in the RRAM film. Further correlations between LFN features and the reset efficiency are found. In addition, CF topography are found to change after long term cycling tests. A trimming process is proposed to minimize the impacts of stochastic CF generation, leading to increase reset speed.INDEX TERMS Variability, resistive random access memory, low frequency noise, Monte Carlo simulation, conductive filament.

An Early Detection Circuit for Endurance Enhancement of Backfilled Contact Resistive Random Access Memory Array

“…To investigate the root cause of reset degradation during cycling, low frequency noise (LFN) found in the read current is investigated and is reported as an index reflecting the properties of CFs [39][40][41]. In our previous work [31], cells with different densities of CFs inside its TMO layers exhibit distinct noise spectrum in its read current. As depicted in Fig.…”

“…b Set/reset time required to complete state switch during 100 k cycles. c Shift in cell type, defined by their noise features, are found during ISPP cycling tests in a dispersed CF, slowing down reset process [31]. As a result, endurance failure on reset operation is attributed to the generation of multiple conductive paths.…”

“…For cells with more CFs inside TMO layers, its read current fluctuates between multiple resistance states. On the contrary, cells with one dominant CFs in RRAM films, current repeatedly jump between two distinct states, which can be used as the indices of the healthy cells [31]. As a result, number of middle states in read current can help us identify the vulnerable cells before it fails completely.…”

“…In our previous work, cells with low reset efficiency were found to correlate to its CF topography. Furthermore, random telegraphic noises are linked to the CF types, which also reflect the change of CF after cycling stress [31]. In this work, new circuits for early detection of weak devices in an array by its read current characteristics have been proposed.…”

Resistive Switching in a MoSe2-Based Memory Device Investigated Using Conductance Noise Spectroscopy

“…Recently, the resistive switching (RS) memory phenomenon, in which the resistance is modulated by electrical stimulation, has been investigated in a wide variety of materials, including metal oxides, perovskites, organics, polymers, and transition metal dichalcogenides (TMDs), for their potential applications. − RS devices based on different organic–inorganic composites have also been investigated for memory and neuromorphic computing applications. − In particular, TMD nanomaterials have garnered considerable attention as a promising nonvolatile memory (NVM) device due to their simple composition, superior scalability, fast switching speed, and low power consumption. − Accordingly, resistive random access memory (RRAM) has emerged as a promising alternative to NAND-based flash technology with multilevel cells (MLCs) and high-density storage capacity. , …”