Study on the degradation mechanism of the ferroelectric properties of thin Hf0.5Zr0.5O2 films on TiN and Ir electrodes

Park, Min Hyuk; Kim, Han Joon; Kim, Yu Jin; Lee, Woongkyu; Moon, Taehwan; Kim, Keum Do; Hwang, Cheol Seong

doi:10.1063/1.4893376

Cited by 146 publications

(85 citation statements)

References 25 publications

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“…However, a maximum value of ≈40 μC cm −2 was recently reported from the La‐doped HfO 2 films, which is quite comparable to the state‐of‐the‐art PZT films with polycrystalline structure . Surprisingly, however, the large P r values of the HfO 2 ‐based films could be achieved from ≈10 nm t f , whereas the t f of PZT films should be 10 2 –10 4 nm to realize its full capability . The small t f of ≈10 nm is a crucial merit for the three‐dimensional capacitor fabrication on nanostructure templates, which is highly required for memory and energy storage applications.…”

Section: Introductionmentioning

confidence: 83%

“…The FE properties of doped HfO 2 films have been reported for various dopants, such as Si, Zr, Y, Al, Gd, Sr, and La . The various experimental works on the FE and AFE properties of Hf 1‐x Zr x O 2 films were also reported by the NaMLab/Fraunhofer CNT collaboration, which were succeeded by the group in Seoul National University, who has focused on the evaluation of the FE and AFE performances and their possible origins for the past three years . The FE and AFE properties of the HfO 2 ‐based films with various dopants will be discussed in detail in Section .…”

Section: Introductionmentioning

confidence: 99%

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Ferroelectricity and Antiferroelectricity of Doped Thin HfO₂‐Based Films

et al. 2015

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The recent progress in ferroelectricity and antiferroelectricity in HfO2-based thin films is reported. Most ferroelectric thin film research focuses on perovskite structure materials, such as Pb(Zr,Ti)O3, BaTiO3, and SrBi2Ta2O9, which are considered to be feasible candidate materials for non-volatile semiconductor memory devices. However, these conventional ferroelectrics suffer from various problems including poor Si-compatibility, environmental issues related to Pb, large physical thickness, low resistance to hydrogen, and small bandgap. In 2011, ferroelectricity in Si-doped HfO2 thin films was first reported. Various dopants, such as Si, Zr, Al, Y, Gd, Sr, and La can induce ferro-electricity or antiferroelectricity in thin HfO2 films. They have large remanent polarization of up to 45 μC cm(-2), and their coercive field (≈1-2 MV cm(-1)) is larger than conventional ferroelectric films by approximately one order of magnitude. Furthermore, they can be extremely thin (<10 nm) and have a large bandgap (>5 eV). These differences are believed to overcome the barriers of conventional ferroelectrics in memory applications, including ferroelectric field-effect-transistors and three-dimensional capacitors. Moreover, the coupling of electric and thermal properties of the antiferroelectric thin films is expected to be useful for various applications, including energy harvesting/storage, solid-state-cooling, and infrared sensors.

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Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Ferroelectricity and Antiferroelectricity of Doped Thin HfO₂‐Based Films

et al. 2015

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“…2. 11,14 Fig. 1c shows the TiN(111) XRD peaks in the y-2y mode from the three samples, revealing that there was no major change in the crystal structure of the TiN layer after the annealing.…”

Section: Methodsmentioning

confidence: 93%

Study on the internal field and conduction mechanism of atomic layer deposited ferroelectric Hf_0.5Zr_0.5O₂ thin films

Park

Kim

et al. 2015

J. Mater. Chem. C

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The internal field (E int ) in ferroelectric films is an important factor which can affect the reliability of practical devices utilizing two memory states which results from the remanent polarizations of ferroelectric films. In the current work, the E int in TiN/Hf 0.5 Zr 0.5 O 2 /TiN capacitors was controlled by changing the annealing atmosphere (N 2 , O 2 , and forming gas). The magnitude of negative E int in O 2 -annealed samples was the largest, whereas that in the forming gas-annealed sample was the smallest. The magnitude of E int can be understood based on the asymmetric distribution of oxygen vacancies near top and bottom TiN electrodes. Despite the large magnitude of E int , the two remanent polarizations can be reliably retained due to the large coercive electric field of Hf 0.5 Zr 0.5 O 2 films, and this is expected to be beneficial for application in semiconductor memory devices. During the repetitive electric field cycling for the wake-up process, the change in E int in O 2 -and forming gas-annealed samples showed the opposite tendency: the magnitude of E int in the O 2 -annealed Hf 0.5 Zr 0.5 O 2 film decreased, whereas that in the forming gas-annealed film increased. This difference is believed to be due to the redistribution of oxygen vacancies with electric field high enough for the migration of oxygen vacancies. The conduction mechanism of electrons through Hf 0.5 Zr 0.5 O 2 films was also examined, and the results fitted best with the Poole-Frenkel emission model with the shallow traps for all the samples with a reasonable optical dielectric constant value for Hf 0.5 Zr 0.5 O 2 .

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“…This phase is not thermodynamically stable at usual processing conditions (several hundred degree Celsius and near atmospheric pressure). The thin film fabrication processes, therefore, appear to induce various (asymmetric) stresses and grain size effects, 10,11 which stabilize the ferroelectric (FE) ophase over the other phases, such as monoclinic (m-phase) or tetragonal (t-phase) phases. HfO 2 -ZrO 2 (HZO) solid solution system is one of the very promising FE materials due to its wide composition range (Hf:Zr ratio) and lower processing temperature (400 -700 o C) for the emergence of these functional properties compared with other doped-HfO 2 , such as Si-doped HfO 2 , which requires precise control of Si concentration (~4%) and high processing temperature (~1000 o C).…”

Section: Introductionmentioning

confidence: 99%

A study on the wake-up effect of ferroelectric Hf_0.5Zr_0.5O₂films by pulse-switching measurement

et al. 2016

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The appearance of ferroelectric (FE) and anti-ferroelectric (AFE) properties in HfO2-based thin films is highly intriguing in terms of both the scientific context and practical application in various electronic and energy-related devices. Interestingly, these materials showed a "wake-up effect", which refers to the increase in remanent polarization with increasing electric field cycling number before the occurrence of the fatigue effect. In this work, the wake-up effect from Hf0.5Zr0.5O2 was carefully examined by the pulse-switching experiment. In the pristine state, the Hf0.5Zr0.5O2 film mostly showed FE-like behavior with a small contribution from AFE-like distortion, which could be ascribed to the involvement of the AFE phase. The field cycling of only 100 cycles almost completely transformed the AFE phase into the FE phase by depinning the pinned domains. The influence of field cycling on the interfacial layer was also examined through the pulse-switching experiments.

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Study on the degradation mechanism of the ferroelectric properties of thin Hf_0.5Zr_0.5O₂ films on TiN and Ir electrodes

Cited by 146 publications

References 25 publications

Ferroelectricity and Antiferroelectricity of Doped Thin HfO₂‐Based Films

Ferroelectricity and Antiferroelectricity of Doped Thin HfO₂‐Based Films

Study on the internal field and conduction mechanism of atomic layer deposited ferroelectric Hf_0.5Zr_0.5O₂ thin films

A study on the wake-up effect of ferroelectric Hf_0.5Zr_0.5O₂films by pulse-switching measurement

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Study on the degradation mechanism of the ferroelectric properties of thin Hf0.5Zr0.5O2 films on TiN and Ir electrodes

Cited by 146 publications

References 25 publications

Ferroelectricity and Antiferroelectricity of Doped Thin HfO2‐Based Films

Ferroelectricity and Antiferroelectricity of Doped Thin HfO2‐Based Films

Study on the internal field and conduction mechanism of atomic layer deposited ferroelectric Hf0.5Zr0.5O2 thin films

A study on the wake-up effect of ferroelectric Hf0.5Zr0.5O2films by pulse-switching measurement

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Study on the degradation mechanism of the ferroelectric properties of thin Hf_0.5Zr_0.5O₂ films on TiN and Ir electrodes

Ferroelectricity and Antiferroelectricity of Doped Thin HfO₂‐Based Films

Ferroelectricity and Antiferroelectricity of Doped Thin HfO₂‐Based Films

Study on the internal field and conduction mechanism of atomic layer deposited ferroelectric Hf_0.5Zr_0.5O₂ thin films

A study on the wake-up effect of ferroelectric Hf_0.5Zr_0.5O₂films by pulse-switching measurement