Li-Doping Effect on Characteristics of ZnO Thin Films Resistive Random Access Memory.

Xiaofeng Zhao,Huiling Gai,Ping Song,Dianzhong Wen,Chunpeng Ai,Yi Li

doi:10.3390/mi11100889

Xiaofeng Zhao, Huiling Gai + Show 4 more

Open Access

https://doi.org/10.3390/mi11100889

Copy DOI

Journal: Micromachines	Publication Date: Sep 24, 2020
Citations: 14	License type: CC BY 4.0

Affiliation: Heilongjiang University

Abstract

In this study, a Pt/Ag/LZO/Pt resistive random access memory (RRAM), doped by different Li-doping concentrations was designed and fabricated by using a magnetron sputtering method. To determine how the Li-doping concentration affects the crystal lattice structure in the composite ZnO thin films, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) tests were carried out. The resistive switching behaviors of the resulting Pt/Ag/LZO/Pt devices, with different Li-doping contents, were studied under direct current (DC) and pulse voltages. The experimental results showed that compared with the devices doped with Li-8% and -10%, the ZnO based RRAM device doped by 5% Li-doping presented stable bipolar resistive switching behaviors with DC voltage, including a low switching voltage (<1.0 V), a high endurance (>103 cycles), long retention time (>104 s), and a large resistive switching window. In addition, quick switching between a high-resistance state (HRS) and a low-resistance state (LRS) was achieved at a pulse voltage. To investigate the resistive switching mechanism of the device, a conduction model was installed based on Ag conducting filament transmission. The study of the resulting Pt/Ag/LZO/Pt devices makes it possible to further improve the performance of RRAM devices.

Highlights

Resistive random access memory (RRAM) has been considered as a promising candidate for generation nonvolatile memory (NVM) devices, due to its significant advantages concerning simplicity of structure, low power consumption, a high level of integration, fast read and write, high tolerance and compatibility, etc. [1,2,3,4]
With the diversification of high performance ZnO-based resistive random access memory (RRAM) devices, especially as more and more memory devices require higher storage density, faster read–write speed, a smaller storage unit, and higher integrated compatibility, it is in no doubt that the ZnO-based RRAM devices with low switching voltage, high ION/IOFF ratio, and uniformity of switching parameters are being pursued [13,14]
To optimize the switching performance of ZnO-based RRAM, a lot of research has been carried out in previous studies to investigate the resistive switching characteristics of ZnO thin films doped by various elements [15,16]

Summary

Introduction

Resistive random access memory (RRAM) has been considered as a promising candidate for generation nonvolatile memory (NVM) devices, due to its significant advantages concerning simplicity of structure, low power consumption, a high level of integration, fast read and write, high tolerance and compatibility, etc. [1,2,3,4]. Simanjuntak et al proposed ITO/Zn1−xCoxO/ITO transparent resistive switching memory devices, achieving a sufficient memory window at an appropriate amount of Co dopant in an ZnO resistive switching layer [18] He et al reported the effects of Pr-doping amount on the resistive switching behaviors of Pt/Zn1−xPrxO/Pt memory cells, improving the performance of devices by lowering the c-axis orientation of Pr-doped ZnO thin films, i.e., achieving a good endurance, a long retention, and a uniform switching voltage [19]. This study on the Pt/Ag/LZO/Pt device makes it possible to fabricate a high performance ZnO-based RRAM device suitable for practical application in the future

Fabrication of Device

10-7 Reset 4