Revealing Resistive Switching Mechanism in CaFeOx Perovskite System with Electroforming-Free and Reset Voltage-Controlled Multilevel Resistance Characteristics

Hung-Yang Lo; Chun-Wei Huang; Chun-Chien Chiu; Jui-Yuan Chen; Fang-Chun Shen; Che-Hung Wang; Yen-Jung Chen; Chien-Hua Wang; Jan-Chi Yang; Wen-Wei Wu

doi:10.1002/smll.202205306

Revealing Resistive Switching Mechanism in CaFeO_x Perovskite System with Electroforming-Free and Reset Voltage-Controlled Multilevel Resistance Characteristics

Small. 2022 Dec;18(51):e2205306. doi: 10.1002/smll.202205306. Epub 2022 Nov 3.

Authors

Affiliations

¹ Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, No.1001, University Rd., East Dist., Hsinchu City, 30010, Taiwan (R.O.C.).
² Department of Materials Science and Engineering, Feng Chia University, No. 100, Wenhwa Rd., Seatwen Dist., Taichung City, 407802, Taiwan (R.O.C.).
³ Department of Physics, National Cheng Kung University, No.1, University Rd., East Dist., Tainan City, 701, Taiwan (R.O.C.).
⁴ Department of Materials Science and Engineering, National United University, No. 2, Lienda, Miaoli City, Miaoli County, 360302, Taiwan (R.O.C.).
⁵ Center for the Intelligent Semiconductor Nano-system Technology Research, National Yang Ming Chiao Tung University, 300, Hsinchu, Taiwan.

PMID: 36328712
DOI: 10.1002/smll.202205306

Abstract

Recently, perovskite (PV) oxides with ABO₃ structures have attracted considerable interest from scientists owing to their functionality. In this study, CaFeO_x is introduced to reveal the resistive switching properties and mechanism of oxygen vacancy transition in PV and brownmillerite (BM) structures. BM-CaFeO_2.5 is grown on an Nb-STO conductive substrate epitaxially. CaFeO_x exhibits excellent endurance and reliability. In addition, the CaFeO_x also demonstrates an electroforming-free characteristic and multilevel resistance properties. To construct the switching mechanism, high-resolution transmission electron microscopy is used to observe the topotactic phase change in CaFeO_x . In addition, scanning TEM and electron energy loss spectroscopy show the structural evolution and valence state variation of CaFeO_x after the switching behavior. This study not only reveals the switching mechanism of CaFeO_x , but also provides a PV oxide option for the dielectric material in resistive random-access memory (RRAM) devices.

Keywords: atomic-scale annular dark-field scanning transmission electron microscopy (ADF-STEM); electroforming-free; multilevel resistance; perovskite oxide system; random-access memory (RRAM).

Abstract

Grants and funding