Shao Yanping, Yang Wanting, Wang Yuanyao, Deng Yuhui, Liao Ningtao, Zhu Bingyan, Lin Xin, Jiang Limei, Jiang Jie, Yang Qiong, Zhong Xiangli
Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan 411105, People's Republic of China.
School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, People's Republic of China.
J Phys Condens Matter. 2022 Aug 4;34(41). doi: 10.1088/1361-648X/ac8513.
In this paper, a phase-field model of Si-doped hafnium oxide-based ferroelectric thin films is established. And then, the synergistic effect of Si concentration and distribution on ferroelectric properties optimization of Si:HfOferroelectric thin films is studied with the proposed model. It is found that no matter how Si dopant is distributed in the film, the volume fraction of the ferroelectric phase in the film increases first and then decreases with the increase of Si concentration. However, compared with the uniform distribution, the layered distribution is more likely to great improve ferrelectric properties. When Si dopant is uniformly distributed in the film, the highest remanent polarization value that the film can obtain via Si concentration modulation is 38.7C cm, and the corresponding Si concentration is 3.8 cat%, which is consistent with the experimental results. When Si dopant is layered in the film, and the concentration difference between the Si-rich and Si-poor layers is 7.6%, in the Si concentration range of 3.6 cat%-3.8 cat%, the residual polarization of the film reaches 46.4-46.8C cm, which is 20% higher than that when Si dopant are evenly distributed in the film. The above results show that selecting the Si layered distribution mode and controlling the concentration difference between Si-rich and Si-poor layers in an appropriate range can greatly improve the films' ferroelectric properties and broaden the Si concentration optimization range of the ferroelectric properties of the films. The result provides further theoretical guidance on using Si doping to adjust the ferroelectric properties of hafnium oxide-based films.
本文建立了硅掺杂氧化铪基铁电薄膜的相场模型。然后，利用所提出的模型研究了硅浓度和分布对Si:HfO铁电薄膜铁电性能优化的协同作用。研究发现，无论硅掺杂剂在薄膜中如何分布，薄膜中铁电相的体积分数均随硅浓度的增加先增大后减小。然而，与均匀分布相比，层状分布更有利于大幅提高铁电性能。当硅掺杂剂均匀分布在薄膜中时，薄膜通过硅浓度调制所能获得的最高剩余极化值为38.7C/cm²，对应的硅浓度为3.8原子%，这与实验结果一致。当硅掺杂剂在薄膜中呈层状分布，且富硅层和贫硅层之间的浓度差为7.6%时，在3.6原子%-3.8原子%的硅浓度范围内，薄膜的剩余极化达到46.4-46.8C/cm²，比硅掺杂剂均匀分布在薄膜中的情况高20%。上述结果表明，选择硅层状分布模式并将富硅层和贫硅层之间的浓度差控制在适当范围内，可以大幅提高薄膜的铁电性能，拓宽薄膜铁电性能的硅浓度优化范围。该结果为利用硅掺杂调节氧化铪基薄膜的铁电性能提供了进一步的理论指导。
