Electronic Structure and Charge-Trapping Characteristics of the Al2O3-TiAlO-SiO2 Gate Stack for Nonvolatile Memory Applications

Wenchao Xu; Yang Zhang; Zhenjie Tang; Zhengjie Shao; Guofu Zhou; Minghui Qin; Min Zeng; Sujuan Wu; Zhang Zhang; Jinwei Gao; Xubing Lu; Junming Liu

doi:10.1186/s11671-017-2040-x

Electronic Structure and Charge-Trapping Characteristics of the Al₂O₃-TiAlO-SiO₂ Gate Stack for Nonvolatile Memory Applications

Nanoscale Res Lett. 2017 Dec;12(1):270. doi: 10.1186/s11671-017-2040-x. Epub 2017 Apr 13.

Authors

Wenchao Xu¹, Yang Zhang¹, Zhenjie Tang², Zhengjie Shao¹, Guofu Zhou³, Minghui Qin¹, Min Zeng¹, Sujuan Wu¹, Zhang Zhang¹, Jinwei Gao¹, Xubing Lu⁴, Junming Liu^{5

6}

Affiliations

¹ Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, and Guangdong Provincial Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, People's Republic of China.
² College of Physics and Electronic Engineering, Anyang Normal University, Anyang, 455000, People's Republic of China.
³ Electronic Paper Displays Institute, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 510006, People's Republic of China.
⁴ Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, and Guangdong Provincial Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, People's Republic of China. [email protected].
⁵ Institute for Advanced Materials, South China Academy of Advanced Optoelectronics, and Guangdong Provincial Laboratory of Quantum Engineering and Quantum Materials, South China Normal University, Guangzhou, 510006, People's Republic of China. [email protected].
⁶ Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, People's Republic of China. [email protected].

Abstract

In this work, high-k composite TiAlO film has been investigated as charge-trapping material for nonvolatile memory applications. The annealing formed Al₂O₃-TiAlO-SiO₂ dielectric stack demonstrates significant memory effects and excellent reliability properties. The memory device exhibits a large memory window of ~2.6 V under ±8 V sweeping voltage, and it shows only ~14% charge loss after more than 10 years' retention, indicating excellent charge retention properties. The electronic structures of the Al₂O₃-TiAlO-SiO₂ have been studied by X-ray photoelectron spectroscopy measurements, and it reveals that the quantum well and the defect traps in TiAlO film can provide a >1.8 eV deep barrier for charge confinement in the TiAlO layer. The mixing between Al₂O₃ and TiO₂ can increase the defects related to the under-coordinated Ti³⁺ atoms, thereby enhancing the charge-trapping efficiency of the device. Our work implies that high-k TiAlO composite film is promising for applications in future nonvolatile charge-trapping memories.

Keywords: Charge trapping; High-k dielectrics; Nonvolatile memory; TiAlO.