Dot‐Product Operation in Crossbar Array Using a Self‐Rectifying Resistive Device

Abstract

unit between vector matrices, the workload of MAC with high-dimensional vector matrices increases exponentially. [4,5] Alternatively, the process-in-memory (PIM) unit, a concept inspired by the human brain, outperforms the von Neumann computing system in unstructured data processing considering it can provide a parallel MAC operation and reduces the time of the data bus between the CPU and the memory.A crossbar array (CA) type device is the most suitable and intuitive structure to achieve the PIM owing to its complex parallel connection of unit memory cells in the CA. [6][7][8] On applying the input signal (voltage bias) to the CA, the output signal (current, input voltage (V) × unit cell conductance (S)) is obtained instantly and simultaneously through each output line by Kirchhoff's law. [9,10] Owing to this "instant and simultaneous" calculation method, the CA-based PIM outperforms the serial process based von-Neumann computing in terms of the operation energy and time. Additionally, the CAbased PIM exhibits an immune response in the MAC operation with vector matrix expansion, which is suitable for processing large amounts of unstructured data.A data storage unit in the CA-based PIM should simultaneously exhibit two types of characteristics: 1) Highly reliable and low-power memory device and 2) device for selection function to suppress the interference effect from the parallel-connected neighboring cells in the CA. Various non-volatile memory devices, such as ferroelectric random access memory (FRAM), phase-change random access memory (PRAM), spin-torquetransfer magnetic random access memory (STT-MRAM), and resistive switching random access memory (RRAM) have been considered for use as a memory element. [11][12][13][14][15][16][17][18][19][20][21][22] Among these devices, the RRAM exhibits outstanding characteristics, such as device scaling down, low power consumption, fast operation speed, simple structure, and high reliability.Various selection devices (SD) such as diodes, [23,24] metalinsulator-transition (MIT) devices, [25,26] ovonic threshold switch (OTS), [27][28][29] mixed-ionic-electronic-conductor (MIEC), [30,31] tunneling-oxide-based devices, [32,33] and timing selector [34] have been proposed to add the selection function to the RRAM devices. Furthermore, a 1-transistor and 1-resistor (1T1R) has been proposed as an active unit cell. [35][36][37] However, stacking SD with RRAM can cause various practical issues. First, tailoring Reducing computational complexity is essential in future computing systems for processing a large amount of unstructured data simultaneously. Dot-product operations using crossbar array devices have attracted considerable attention owing to their simple device structure, intuitive operation scheme, and high computational efficiency of parallel operation. The resistive switching device is considered a promising candidate as the main data storage in the crossbar array owing to its highly reliable performance. In this study, a tri-layer TaO x /Al 2 O 3 /Ti:SiO x -based resistive...

Analogue Artificial Synaptic Performance of Self‐Rectifying Resistive Switching Device

“…In detail, the degradation of retention characteristic in the interfacetype RS can be improved by the insertion of oxygen reservoir layer with the oxide-based RS layer. [22,23] In case of low resistance ratio, the insertion of thin insulating layer with the RS layer can enhance the resistance ratio by increasing the resistance of HRS. [24] However, because this method also increases the operational voltage for programming of the RS device, the optimized structure and material for the insulating layer should be considered.…”

Sparse matrix multiplication in a record-low power self-rectifying memristor array for scientific computing

“…2C. Commonly, the SRMs exhibit forming-free characteristics (27)(28)(29)(30)(31)(32)(33)(34)(35) similar to the proposed SRM cell, as shown in Fig. 2D.…”

“…Owing to its self-rectifying nature, the SRM can substantially outperform other nonvolatile memories, such as the phase-change memory (PCM) and resistive random-access memory (ReRAM), for high-density integration without additional selective devices [4F 2 footprint and prominent three-dimensional (3D) scalability]. Moreover, with their ultralow operating current (down to picoampere level), SRM shows great potential to construct energy-efficient mIMC systems for data-intensive tasks (27)(28)(29)(30)(31)(32)(33). Our SRM cells were fabricated with a vertical stack structure of Pt/HfO 2 /TaO x /Ta (Fig.…”

Highly parallel stateful Boolean logic gates based on aluminum-doped self-rectifying memristors in a vertical crossbar array structure

“…However, this independent switching may not be the case, but additional adverse switching occurs in the PTA:HT device. 20,23,26,27…”

“…However, this independent switching may not be the case, but additional adverse switching occurs in the PTA:HT device. 20,23,26,27 Since the reset process of the electronic bipolar resistive switching memristors is the de-trapping of electrons from the trap states, the de-trapped electrons can fill the trap states in the adjacent memristor, connected to the switching memristor via metal wires. Fig.…”