Effects of Work Function and Thermal Stability of Top Electrode Materials on Electrical Properties of ZrO2-Based DRAM Capacitors

IF 2.6 4区材料科学 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY

Electronic Materials Letters Pub Date : 2025-05-08 DOI:10.1007/s13391-025-00573-9

Hyeongjun Kim, Kyungmin Choi, Hojin Lee, Woongkyu Lee

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Abstract

The effects of work function and thermal stability of top electrode (TE) materials on the electrical properties of TE/ZrO₂/TiN capacitors for dynamic random-access memory applications were investigated. TEs of Au, Ag, and Al were deposited via thermal evaporation on the atomic-layer-deposited ZrO₂ dielectric layer on a TiN bottom electrode. The high work function of 5.1 eV of Au induced a very stable insulating property, while Ag and Al showed relatively higher leakage current with equivalent dielectric layer fabrication process. To evaluate the interfacial properties between the electrode and dielectric as well as the thermal stability of the electrode, post-metallization annealing (PMA) was performed in an air ambient at 400 °C for 30 min. Ag⁺ ion was diffused into the ZrO₂ layer and Al was oxidized to Al₂O₃ at the interface for Ag and Al TEs, respectively, and severe capacitance degradation occurred. However, Au TE exhibited superior interfacial properties after PMA owing to a curing effect that promoted reducing oxygen vacancies and imperfections near the TE interface, and improved both dielectric and insulating properties.

Graphical abstract

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顶电极材料的功函数和热稳定性对zro2基DRAM电容器电性能的影响

研究了顶电极（TE）材料的功函数和热稳定性对动态随机存取存储器用TE/ZrO2/TiN电容器电性能的影响。将Au、Ag和Al的te通过热蒸发沉积在TiN底电极上原子层沉积的ZrO2介电层上。Au的高功函数（5.1 eV）产生了非常稳定的绝缘性能，而Ag和Al在等效介质层制作工艺下表现出相对较高的泄漏电流。为了评估电极和电介质之间的界面性能以及电极的热稳定性，在400°C的空气环境中进行金属化后退火（PMA） 30分钟。Ag+离子扩散到ZrO2层，Al分别在Ag和Al TEs的界面处氧化为Al2O3，发生了严重的电容退化。然而，经过PMA处理的Au TE表现出优异的界面性能，因为固化效应促进了TE界面附近氧空位和缺陷的减少，并提高了介电和绝缘性能。图形抽象

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来源期刊

Electronic Materials Letters 工程技术-材料科学：综合

CiteScore

4.70

自引率

20.80%

发文量

审稿时长

2.3 months

期刊介绍： Electronic Materials Letters is an official journal of the Korean Institute of Metals and Materials. It is a peer-reviewed international journal publishing print and online version. It covers all disciplines of research and technology in electronic materials. Emphasis is placed on science, engineering and applications of advanced materials, including electronic, magnetic, optical, organic, electrochemical, mechanical, and nanoscale materials. The aspects of synthesis and processing include thin films, nanostructures, self assembly, and bulk, all related to thermodynamics, kinetics and/or modeling.