High-Performance Resistive Switching in Solution-Derived IGZO:N Memristors by Microwave-Assisted Nitridation.

Shin-Yi Min,Won-Ju Cho

doi:10.3390/nano11051081

Abstract

In this study, we implemented a high-performance two-terminal memristor device with a metal/insulator/metal (MIM) structure using a solution-derived In-Ga-Zn-Oxide (IGZO)-based nanocomposite as a resistive switching (RS) layer. In order to secure stable memristive switching characteristics, IGZO:N nanocomposites were synthesized through the microwave-assisted nitridation of solution-derived IGZO thin films, and the resulting improvement in synaptic characteristics was systematically evaluated. The microwave-assisted nitridation of solution-derived IGZO films was clearly demonstrated by chemical etching, optical absorption coefficient analysis, and X-ray photoelectron spectroscopy. Two types of memristor devices were prepared using an IGZO or an IGZO:N nanocomposite film as an RS layer. As a result, the IGZO:N memristors showed excellent endurance and resistance distribution in the 103 repeated cycling tests, while the IGZO memristors showed poor characteristics. Furthermore, in terms of electrical synaptic operation, the IGZO:N memristors possessed a highly stable nonvolatile multi-level resistance controllability and yielded better electric pulse-induced conductance modulation in 5 × 102 stimulation pulses. These findings demonstrate that the microwave annealing process is an effective synthesis strategy for the incorporation of chemical species into the nanocomposite framework, and that the microwave-assisted nitridation improves the memristive switching characteristics in the oxide-based RS layer.

Highlights

Over the past few decades, information science technology and electronic applications have required versatile electrical units, computing methods, and materials [1,2]
The electron transport paths in the conduction band (Ec) of IGZO nanocomposites mainly consist of overlapping spherical In 5 s-orbitals, and the free carriers can be provided from defects such as oxygen vacancies and metal ion interstitials [21,22]
The IGZO thin film is a well-known n-type oxide-semiconductor that consists of ionically bonded heavy metal cations with an electronic configuration of (n − 1)d10 ns0 (n ≥ 4) [19,20]

Summary

Introduction

Over the past few decades, information science technology and electronic applications have required versatile electrical units, computing methods, and materials [1,2]. The metal/insulator/metal (MIM) sandwich structure is geometrically simple, and these memristor devices possess promising features such as high scalability, low-power consumption, nonvolatile data storage, and multi-resistance state controllability. The resistance state of memristors can be gradually modulated in the insulator layer, and various resistive switching (RS) methods such as ferroelectric switching, phase-change switching, and oxide-based switching have been reported [7,8,9] Among these methods, the oxide-based RS behaviors can be realized in a simple material combination, and they exhibit characteristics such as stable mechanical strength, thermal stability, and symmetrical resistance modulation, contrary to ferroelectric-based or phase-change-based switching [10,11]

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Results

Conclusion