Ferroelectricity in dopant-free HfO2 thin films prepared by pulsed laser deposition
Ferroelectricity in dopant-free HfO2 thin films prepared by pulsed laser deposition
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脉冲激光沉积制备的无掺杂 HfO2 薄膜中的铁电性
DOI：
10.1016/j.jmat.2021.09.005
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发表时间：
2022-02-16
影响因子：
9.4
通讯作者：
Liu, Jun -Ming
中科院分区：
文献类型：
--
作者：
Luo, Yongjian;Tang, Zhenxun;Liu, Jun -Ming
作为一种高k材料，氧化铪（HfO 2）已被用于栅介质中数十年。自从发现掺硅HfO 2薄膜中存在极性相以来，化学掺杂被广泛认为是稳定HfO 2基薄膜铁电相的有效方法。然而，通常需要额外的覆盖层沉积，生长后退火和唤醒效应，以激发HfO 2基薄膜的铁电性，导致样品合成的复杂性增加和器件应用的障碍。在这项研究中，观察到铁电性的非加盖无掺杂的HfO 2薄膜制备脉冲激光沉积（PLD）没有生长后退火。通过调节沉积温度、氧分压和膜厚，在7.4nm厚的膜中获得了最大极化强度达14.7 μ C/cm ~（2）的薄膜。正交相的分数，缺陷的浓度和尺寸效应被认为是可能的机制的铁电性能的影响。研究表明，PLD是一种无需化学掺杂、覆盖层沉积和生长后退火的制备高质量HfO 2铁电薄膜的有效技术，有望推动非易失性存储器件的应用进程。(C)2021中国陶瓷学会由爱思唯尔公司制作和主持
As a high-k material, hafnium oxide (HfO2) has been used in gate dielectrics for decades. Since the discovery of polar phase in Si-doped HfO2 films, chemical doping has been widely demonstrated as an effective approach to stabilize the ferroelectric phase in HfO2 based thin films. However, the extra capping layer deposition, post-growth annealing and wake-up effect are usually required to arouse the ferroelectricity in HfO2 based thin films, resulting in the increase of complexity for sample synthesis and the impediment of device application. In this study, the ferroelectricity is observed in non-capped dopant-free HfO2 thin films prepared by pulsed laser deposition (PLD) without post-growth annealing. By adjusting the deposited temperature, oxygen pressure and thickness, the maximum polarization up to 14.7 mu C/cm(2) was obtained in 7.4 nm-thick film. The fraction of orthorhombic phase, concentrations of defects and size effects are considered as possible mechanisms for the influences of ferroelectric properties. This study indicates that PLD is an effective technique to fabricate high-quality ferroelectric HfO2 thin films in the absence of chemical doping, capping layer deposition and post-growth annealing, which may boost the process of nonvolatile memory device application. (C) 2021 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.