Composition-Dependent Ferroelectric Properties in Sputtered HfXZr1−XO2 Thin Films

Luo, Qing; Ma, Haili; Su, Hai-Lei; Xue, Kan‐Hao; Cao, Rongrong; Gao, Zhaomeng; Yu, Jie; Gong, Tiancheng; Xu, Xiaoxin; Yin, Jigang; Yuan, Peng; Tai, Lu; Dong, Danian; Long, Shibing; Liu, Qi; Miao, Xiangshui; Lv, Hangbing; Liu, Ming

doi:10.1109/led.2019.2902609

Cited by 38 publications

(29 citation statements)

References 25 publications

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“…[30,38,39]. This phase has been observed (and sometimes assumed) in polycrystalline ferroelectric layers grown via atomic layer deposition (ALD) [1,10,40,41], chemical solution deposition (CSD) [42], RF sputtering [43,44], co-evaporation and plasma assisted atomic oxygen deposition [40], as well as epitaxial layers obtained via pulsed laser deposition (PLD) [25,[33][34][35]37,45,46]. Recently, a higher energy polar rhombohedral (r-) phase has been observed on Hf 0.5 Zr 0.5 O 2 (HZO) layers epitaxially grown on SrTiO 3 (STO) substrates buffered with La 0.7 Sr 0.3 MnO 3 (LSMO) as the back-electrode [30].…”

Section: Introductionmentioning

confidence: 99%

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf_0.5Zr_0.5O₂ thin films

et al. 2020

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The unconventional Si-compatible ferroelectricity in hafnia-based systems, which becomes robust only at nanoscopic sizes, has attracted a lot of interest. While a metastable polar orthorhombic (o-) phase ( Pca21) is widely regarded as the responsible phase for ferroelectricity, a higher energy polar rhombohedral (r-) phase is recently reported on epitaxial HfZrO4 (HZO) films grown on (001) SrTiO3 (R3m or R3), (0001) GaN (R3), and Si (111). Armed with results on these systems, here we report a systematic study leading towards identifying comprehensive global trends for stabilizing r-phase polymorphs in epitaxially grown HZO thin films (6 nm) on various substrates (perovskites, hexagonal and Si).

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Section: Introductionmentioning

confidence: 99%

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf_0.5Zr_0.5O₂ thin films

et al. 2020

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“…However, it is yet to be confirmed if the LGD theory is also applicable to HfO 2 ‐based ferroelectric materials. At present, the ferroelectricity in HfO 2 ‐based films is believed to originate from orthorhombic phase with the space group Pca2 1 , [ 41,42 ] which is metastable and non‐centrosymmetric. In addition, there are also some other proposed phenomena, for example, the wake‐up effect, but a unified mechanism explanation of the respective mechanism has not been elucidated.…”

Section: Introductionmentioning

confidence: 99%

Wake‐Up Effect in HfO₂‐Based Ferroelectric Films

Jiang

Luo

et al. 2020

Adv Elect Materials

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HfO2‐based ferroelectric materials are promising candidates for next‐generation nonvolatile memories. Since the first report on Si‐doped HfO2 ferroelectric thin film in 2011, it has been confirmed that various dopants can induce ferroelectricity in HfO2‐based films, and the “wake‐up” effect in HfO2 films with different dopants deposited by different processes has been studied extensively. Recent developments in the wake‐up effect of doped HfO2‐based films are presented. Aside from the differences between the various ferroelectric materials and their deposition methods, the electrodes used in a ferroelectric capacitor, which determine the nature of the interface between the electrode and the ferroelectric layer, can strongly influence the characteristics of the wake‐up effect. The rate of variation of the remanent polarization shows certain trends with different dopants. Based on the wake‐up mechanisms, many methods to optimize and control this effect are presented in this letter. Until now, the reported mechanism explanations of the wake‐up effect all aimed at one type of specific dopant or deposition technique, but can't systematically interpret why the root causes might be different with different dopants and deposition processes. There is also a lack of in‐depth research on the effects of interfacial layer with respect to different electrode material.

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“…The ferroelectric layers have typically been grown so far with the atomic layer deposition (ALD) technique, which allows sophisticated composition control. However, as an alternative, the sputtering process to deposit the doped HfO 2 not only allows the polarization switching to be observed, but also enables a cost-effective process that significantly reduces the deposition time compared to the ALD [ 25 , 26 , 27 ]. In general, the ferroelectricity is shown in the HfZrO x (HZO) materials after annealing at high temperatures that drive phase transformation into the orthorhombic crystalline phase.…”

Section: Introductionmentioning

confidence: 99%

Ferroelectric Switching in Trilayer Al2O3/HfZrOx/Al2O3 Structure

Kang

Kim

et al. 2020

Micromachines

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Since ferroelectricity has been observed in simple binary oxide material systems, it has attracted great interest in semiconductor research fields such as advanced logic transistors, non-volatile memories, and neuromorphic devices. The location in which the ferroelectric devices are implemented depends on the specific application, so the process constraints required for device fabrication may be different. In this study, we investigate the ferroelectric characteristics of Zr doped HfO2 layers treated at high temperatures. A single HfZrOx layer deposited by sputtering exhibits polarization switching after annealing at a temperature of 850 °C. However, the achieved ferroelectric properties are vulnerable to voltage stress and higher annealing temperature, resulting in switching instability. Therefore, we introduce an ultrathin 1-nm-thick Al2O3 layer at both interfaces of the HfZrOx. The trilayer Al2O3/HfZrOx/Al2O3 structure allows switching parameters such as remnant and saturation polarizations to be immune to sweeping voltage and pulse cycling. Our results reveal that the trilayer not only makes the ferroelectric phase involved in the switching free from pinning, but also preserves the phase even at high annealing temperature. Simultaneously, the ferroelectric switching can be improved by preventing leakage charge.

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Composition-Dependent Ferroelectric Properties in Sputtered Hf_XZr_1−XO₂ Thin Films

Cited by 38 publications

References 25 publications

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf_0.5Zr_0.5O₂ thin films

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf_0.5Zr_0.5O₂ thin films

Wake‐Up Effect in HfO₂‐Based Ferroelectric Films

Ferroelectric Switching in Trilayer Al2O3/HfZrOx/Al2O3 Structure

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Composition-Dependent Ferroelectric Properties in Sputtered HfXZr1−XO2 Thin Films

Cited by 38 publications

References 25 publications

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf0.5Zr0.5O2 thin films

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf0.5Zr0.5O2 thin films

Wake‐Up Effect in HfO2‐Based Ferroelectric Films

Ferroelectric Switching in Trilayer Al2O3/HfZrOx/Al2O3 Structure

Contact Info

Product

Resources

About

Composition-Dependent Ferroelectric Properties in Sputtered Hf_XZr_1−XO₂ Thin Films

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf_0.5Zr_0.5O₂ thin films

Guidelines for the stabilization of a polar rhombohedral phase in epitaxial Hf_0.5Zr_0.5O₂ thin films

Wake‐Up Effect in HfO₂‐Based Ferroelectric Films