Composition-Dependent Ferroelectric Properties in Sputtered HfXZr1-XO2 Thin Films
Composition-Dependent Ferroelectric Properties in Sputtered HfXZr1-XO2 Thin Films
复制标题
溅射 HfXZr1-XO2 薄膜中与成分相关的铁电特性
DOI：
10.1109/led.2019.2902609
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发表时间：
2019-04-01
影响因子：
4.9
通讯作者：
Liu, Ming
中科院分区：
文献类型：
--
作者：
Luo, Qing;Ma, Haili;Liu, Ming
具有钙钛矿结构的铁电材料具有各种缺点，包括差的Si相容性、大的物理厚度和小的带隙。HfO 2基铁电材料为铁电半导体器件提供了一种新的解决方案。HfO_2-ZrO_2固溶体（HZO）薄膜由于具有较低的晶化温度和较宽的化学计量比范围而得到了广泛的研究。溅射法由于其成本低、沉积条件灵活等优点，是制备HZO薄膜的一种有效方法。然而，溅射HZO铁电薄膜的报道很少，成分对HfXZr 1-XO 2薄膜铁电性能的影响尚不清楚。在这封信中，溅射HfXZr 1-XO 2薄膜进行了研究与不同的Zr含量（从12.49至20.34摩尔%），通过改变溅射功率比的ZrO 2 HfO 2。我们发现HfXZr_（1-x）O_2体系中具有最佳铁电性能的掺杂浓度约为15-16 mol%，远低于ALD基HZO薄膜中的掺杂浓度。第一性原理计算表明，氧空位的掺杂导致了HZO薄膜中不同相的亥姆霍兹自由能发生变化，从而影响了最大铁电极化的最佳Zr浓度。
Ferroelectric materials with a perovskite structure have various shortcomings, including poor Si compatibility, large physical thickness, and small bandgap. HfO2-based ferroelectric materials provide a new solution for ferroelectric semiconductor devices. HfO2-ZrO2 solid solution (HZO) thin films have been widely studied due to their low crystallization temperature and wide stoichiometric range. Considering its low cost and flexible deposition conditions, the sputtering technique is a useful method for HZO deposition. However, sputtered HZO ferroelectric films have been rarely reported, and the composition effect on the ferroelectric properties of HfXZr1-XO2 thin films is still unclear. In this letter, sputtered HfXZr1-XO2 thin films were studied with different Zr contents (from 12.49 to 20.34 mol%) by varying the sputtering power ratio of ZrO2 to HfO2. We found that the dopant concentration with the best ferroelectric properties in the HfXZr1-XO2 system is similar to 15-16 mol%, which is much lower than that in the ALD-based HZO film. First-principle calculation shows that oxygen vacancies doped in the HZO film lead to a change in the Helmholtz free energy of different phases, which affected the optimal Zr concentration for the largest ferroelectric polarization.