Demonstration of synaptic and resistive switching characteristics in W/TiO_(2)/HfO_(2)/TaN memristor crossbar array for bioinspired neuromorphic computing  

作　　者：Muhammad Ismail Umesh Chand Chandreswar Mahata Jamel Nebhen Sungjun Kim 

机构地区：[1]Division of Electronics and Electrical Engineering,Dongguk University,Seoul 04620,South Korea [2]Department of Electrical and Computer Engineering,National University Singapore,Singapore 117583,Singapore [3]College of Computer Engineering and Sciences,Prince Sattam bin Abdulaziz University,Al-Kharj 11942,Saudi Arabia

出　　处：《Journal of Materials Science & Technology》2022年第1期94-102,共9页材料科学技术（英文版）

基　　金：financially supported in part by a grant(2021R1C1C1004422)of the National Research Foundation(NRF)grant funded by the Korean government(MSIP)。

摘　　要：In this study,resistive random-access memory(RRAM)-based crossbar arrays with a memristor W/TiO_(2)/HfO_(2)/TaN structure were fabricated through atomic layer deposition(ALD)to investigate synaptic plasticity and resistive switching(RS)characteristics for bioinspired neuromorphic computing.X-ray photoelectron spectroscopy(XPS)was employed to explore oxygen vacancy concentrations in bilayer TiO_(2)/HfO_(2)films.Gaussian fitting for O1s peaks confirmed that the HfO_(2)layer contained a larger number of oxygen vacancies than the TiO_(2)layer.In addition,HfO_(2)had lower Gibbs free energy(ΔG°=-1010.8 kJ/mol)than the TiO_(2)layer(ΔG°=-924.0 kJ/mol),resulting in more oxygen vacancies in the HfO_(2)layer.XPS results andΔG°magnitudes confirmed that formation/disruption of oxygen-based conductive filaments took place in the TiO_(2)layer.The W/TiO_(2)/HfO_(2)/TaN memristive device exhibited excellent and repeatable RS characteristics,including superb 10^(3) dc switching cycles,outstanding 107 pulse endurance,and high-thermal stability(10^(4) s at 125℃)important for digital computing systems.Furthermore,some essential biological synaptic characteristics such as potentiation-depression plasticity,paired-pulse facilitation(PPF),and spike-timing-dependent plasticity(STDP,asymmetric Hebbian and asymmetric anti-Hebbian)were successfully mimicked herein using the crossbar-array memristive device.Based on experimental results,a migration and diffusion of oxygen vacancy based physical model is proposed to describe the synaptic plasticity and RS mechanism.This study demonstrates that the proposed W/TiO_(2)/HfO_(2)/TaN memristor crossbar-array has a significant potential for applications in non-volatile memory(NVM)and bioinspired neuromorphic systems.

关 键 词：Resistive switching Crossbar-array memristive device Synaptic plasticity TiO_(2)/HfO_(2)film Oxygen vacancy 

分 类 号：TB383.2[一般工业技术—材料科学与工程] TP333[自动化与计算机技术—计算机系统结构]