Advances of RRAM Devices: Resistive Switching Mechanisms, Materials and Bionic Synaptic Application

Abstract

Resistive random access memory (RRAM) devices are receiving increasing extensive attention due to their enhanced properties such as fast operation speed, simple device structure, low power consumption, good scalability potential and so on, and are currently considered to be one of the next-generation alternatives to traditional memory. In this review, an overview of RRAM devices is demonstrated in terms of thin film materials investigation on electrode and function layer, switching mechanisms and artificial intelligence applications. Compared with the well-developed application of inorganic thin film materials (oxides, solid electrolyte and two-dimensional (2D) materials) in RRAM devices, organic thin film materials (biological and polymer materials) application is considered to be the candidate with significant potential. The performance of RRAM devices is closely related to the investigation of switching mechanisms in this review, including thermal-chemical mechanism (TCM), valance change mechanism (VCM) and electrochemical metallization (ECM). Finally, the bionic synaptic application of RRAM devices is under intensive consideration, its main characteristics such as potentiation/depression response, short-/long-term plasticity (STP/LTP), transition from short-term memory to long-term memory (STM to LTM) and spike-time-dependent plasticity (STDP) reveal the great potential of RRAM devices in the field of neuromorphic application.

Emulation of Biological Synapse Characteristics from Cu/AlN/TiN Conductive Bridge Random Access Memory

“…Neuromorphic systems are attracting attention as replacements for von Neumann architecture in the near future due to their capacity for energy efficient, massively parallel, and error tolerant computing [1][2][3][4]. Two-terminal resistive switching memory possesses many features that are suitable for synaptic devices for neuromorphic systems, such as low-power operation, high scalability, analogue switching for multi-level cells (MLCs), fast switching, high endurance, and long retention [5][6][7][8][9][10]. The various resistive switching behaviors have been observed from a lot of materials such as oxides, nitrides, and chalcogenides [11,12].…”

Improved Device Distribution in High-Performance SiNx Resistive Random Access Memory via Arsenic Ion Implantation

“…In the past few decades, resistive random access memory (RRAM) has attracted massive attention due to its simple process, high density, multilevel state, high operation speed, and low power consumption [1][2][3][4][5]. The RRAM device has high potential to be implemented for artificial intelligence (Al) and neuromorphic computing [6,7] in several kinds of emerging memories.…”

Improved Synaptic Device Properties of HfAlOx Dielectric on Highly Doped Silicon Substrate by Partial Reset Process

“…RRAM has been found to have a memory switching effect in a variety of dielectric materials. Basically, low-resistance state (LRS) and high-resistance state (HRS) can be converted according to the applied voltage, and the state, once stored, has a nonvolatile characteristic that is maintained over time [4][5][6][7]. Among a lot of materials, metal oxides like TiO 2 , HfO 2 and Ta 2 O 5 are the most popular resistive switching materials due to their superior memory device behaviors, such as endurance, stability, repeatability, and reproducibility [8][9][10][11][12][13][14][15].…”