Excellent selector performance in engineered Ag/ZrO2:Ag/Pt structure for high-density bipolar RRAM applications

Chao Wang,Bing Song,Zhongming Zeng

doi:10.1063/1.5009717

Abstract

A high-performance selector with bidirectional threshold switching (TS) characteristics of Ag/ZrO2/Pt structure was prepared by incorporating metallic Ag into the ZrO2 matrix. The bidirectional TS device exhibited excellent switching uniformity, forming-free behavior, ultra-low off current of &lt;1 nA and adjustable selectivity (from 102 to 107). The experiment results confirmed that metallic Ag clusters were penetrated into the ZrO2 matrix during the annealing process, which would function as an effective active source responsible for the bidirectional TS. The volatile behavior could be explained by the self-dissolution of unstable filaments caused by minimization of the interfacial energy and thermal effect. Furthermore, a bipolar-type one selector-one resistor (1S-1R) memory device was successfully fabricated and exhibited significant suppression of the undesired sneak current, indicating the great potential as selector in a cross-point array.

Highlights

Resistance random access memory (RRAM) devices have recently attracted significant attention for memory, logic and neuromorphic applications.[1,2] Among them, electrochemical metallization memory (ECM) devices have shown excellent resistive switching properties such as fast programming speed, large memory window, low power consumption, and high storage density.[3,4,5] The simplicity of the metal–insulator–metal (MIM) structure enables RRAM to be integrated in passive crossbar arrays and to achieve the highest storage capacity with the smallest cell size of 4F2/n (F is the minimum feature size; n is the stacking layer number of the crossbar arrays).[6]
Several types of selector devices have been extensively investigated because of their promising selection properties, including a metal-insulator transition (MIT) device,[8] and Ovonic threshold switching (OTS) device.[9]. These selector devices cannot sufficiently suppress the leakage current, which are not meet the requirement for achieving high density RRAM integration
We found a proper bipolar RRAM device which was well-matched with the bipolar selector

Summary

Introduction

Resistance random access memory (RRAM) devices have recently attracted significant attention for memory, logic and neuromorphic applications.[1,2] Among them, electrochemical metallization memory (ECM) devices have shown excellent resistive switching properties such as fast programming speed, large memory window, low power consumption, and high storage density.[3,4,5] The simplicity of the metal–insulator–metal (MIM) structure enables RRAM to be integrated in passive crossbar arrays and to achieve the highest storage capacity with the smallest cell size of 4F2/n (F is the minimum feature size; n is the stacking layer number of the crossbar arrays).[6]. Excellent selector performance in engineered Ag/ZrO2:Ag/Pt structure for high-density bipolar RRAM applications

Results

Conclusion