无机材料学报 ›› 2022, Vol. 37 ›› Issue (6): 596-602.DOI: 10.15541/jim20210437

所属专题: 【信息功能】电介质材料

• 研究论文 • 上一篇    下一篇

硅片上集成高介电调谐率的柱状纳米晶BaTiO3铁电薄膜

赵玉垚1(), 欧阳俊1,2()   

  1. 1.山东大学 材料科学与工程学院, 材料液固结构演变与加工教育部重点实验室, 济南 250061
    2.齐鲁工业大学(山东省科学院) 化学与化工学院, 济南 250353
  • 收稿日期:2021-07-13 修回日期:2021-08-25 出版日期:2022-06-20 网络出版日期:2021-08-20
  • 通讯作者: 欧阳俊, 男, 教授. E-mail: ouyangjun@qlu.edu.cn
  • 作者简介:赵玉垚(1994-), 男, 博士研究生. E-mail: zhaoyuyao920606@163.com
  • 基金资助:
    国家自然科学基金(51772175);国家自然科学基金(11672036);济南市“新高校20条”项目(2021GXRC055);济南市“新高校20条”项目(济南市科技局)

Columnar Nanograined BaTiO3 Ferroelectric Thin Films Integrated on Si with a Sizable Dielectric Tunability

ZHAO Yuyao1(), OUYANG Jun1,2()   

  1. 1. Key Laboratory for Liquid-Solid Structure Evolution and Processing of Materials, School of Materials Science and Engineering, Shandong University, Jinan 250061, China
    2. School of Chemistry and Chemical Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China
  • Received:2021-07-13 Revised:2021-08-25 Published:2022-06-20 Online:2021-08-20
  • Contact: OUYANG Jun, male, professor. E-mail: ouyangjun@qlu.edu.cn
  • About author:ZHAO Yuyao (1994–), male, PhD candidate. E-mail: zhaoyuyao920606@163.com
  • Supported by:
    National Natural Science Foundation of China(51772175);National Natural Science Foundation of China(11672036);Jinan “New Universities” 20 Project(2021GXRC055);Jinan “New Universities” 20 Project(Science and Technology Bureau of Jinan)

摘要:

钛酸钡(BaTiO3)具有优异的介电、铁电、压电和热释电等性能, 在微电子机械系统和集成电路领域具有广泛的应用。降低BaTiO3薄膜的制备温度使其与现有的CMOS-Si工艺兼容, 已成为应用研究和技术开发中亟需解决的问题。本研究引入与BaTiO3晶格常数相匹配的LaNiO3作为缓冲层, 以调控其薄膜结晶取向, 在单晶Si(100)基底上450 ℃溅射制备了结构致密的柱状纳米晶BaTiO3薄膜。研究表明:450 ℃溅射温度在保持连续柱状晶结构和(001)择优取向的前提下, 能获得相对较大的柱状晶粒(平均晶粒直径27 nm), 一定残余应变也有助于其获得了较好的铁电和介电性能。剩余极化强度和最大极化强度分别达到了7和43 μC·cm-2。该薄膜具有良好的绝缘性, 在 0.8 MV·cm-1电场下, 漏电流密度仅为10-5 A·cm-2。其相对介电常数εr展现了优异的频率稳定性:在1 kHz时εr为155, 当测试频率升至1 MHz, εr仅轻微降低至145。薄膜的介电损耗较小, 约为0.01~0.03 (1 kHz ~ 1 MHz)。通过电容-电压测试, 该薄膜材料展示出高达51%的介电调谐率, 品质因子亦达到17(@1 MHz)。本研究所获得的BaTiO3薄膜在介电调谐器件中有着良好的应用前景。

关键词: 硅, BaTiO3, 铁电薄膜, 柱状纳米晶, 介电调谐率, 品质因子

Abstract:

BaTiO3 has a wide range of applications in microelectromechanical systems and integrated circuits due to its excellent dielectric, ferroelectric, piezoelectric, and pyroelectric properties. For the applied research and device applications of BaTiO3 films, reducing its deposition temperature to be compatible with the CMOS-Si technology is an important Challenge. Here, with the help of a LaNiO3 buffer layer which has a closely-matched lattice with BaTiO3, (001)-textured BaTiO3 films were sputter-deposited at 450 ℃ on single crystalline Si(100) substrates, which consisting of well-cryotallized, evenly-distributed columnar nanograins with an average grain size of 27 nm. Our result showed that this deposition temperature can maintain the columnar nanograin structure with a relatively large grain size, leading to a good ferroelectric performance. In addition, a small residual strain on Si was also helpful to improve its ferroelectric and dielectric properties. The remnant polarization and saturated polarization of these BaTiO3 films reached 7 and 43 μC·cm-2, respectively, while leakage current densities were as low as 10-5 A·cm-2 at an applied electric field of 0.8 MV·cm-1. These BaTiO3 films also displayed excellent frequency stability with a low dielectric loss in which relative dielectric constant measured to be ~155 at 1 kHz, slightly being reduced to ~145 after increasing the frequency to 1 MHz. Meanwhile, the dielectric loss slightly increased from 0.01 at 1 kHz to 0.03 at 1 MHz. Lastly, through capacitance-voltage (C-V) tests, these films exhibited a large dielectric tunability of~51% and a figure of merit (FOM) of ~17 (@1 MHz). These films have a good potential for applications in tunable dielectrics.

Key words: silicon, BaTiO3, ferroelectric film, columnar nanograins, dielectric tunability, figure of merit

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