Study on the effect of heat treatment conditions on metalorganic-chemical-vapor-deposited ferroelectric Hf0.5Zr0.5O2thin film on Ir electrode

Shiraishi, Takashi; Yokouchi, Tatsuhiko; Shiraishi, Takahisa; Oikawa, Takahiro; Krishnan, P. S. Sankara Rama; Funakubo, Hioshi

doi:10.7567/jjap.53.09pa04

Cited by 66 publications

(56 citation statements)

References 31 publications

(40 reference statements)

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“…Seo et al reported that the rutile TiO 2 phase could hinder the m-phase formation of HfO 2 and support the t-phase formation due to the small lattice mismatch between them (rutile-TiO 2 and t-phase HfO 2 ). [56,57] TiN top electrode layer induced a tensile stress effect on the HZO film, which was why PMA samples usually showed more enhanced ferroelectric behavior than PDA samples. [55] Retardation of the m-phase growth may not be solely attributed to the rutile TiO 2 formation, but the experimental results evidently show that the m-phase formation decreased once rutile TiO 2 phase had formed.…”

Section: Resultsmentioning

confidence: 99%

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf_0.5Zr_0.5O₂ Thin Films

Lee

Hyun

Kim

et al. 2018

Adv Elect Materials

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Various possibilities have been proposed as the cause of the doped‐ or undoped‐HfO2 thin film materials showing unusual ferroelectricity. These assumptions are based on empirical results, yet finding the origin of the unprecedented ferroelectricity within HfO2 has suffered from a serious gap between its theoretical calculation, mostly based on thermodynamic approach and the actual experimental results. To fill the gap, this study proposes to consider the kinetic energy, providing the evidence of the kinetic energy barrier upon a phase transformation from the tetragonal phase to the monoclinic phase affected by the TiN top electrode (capping layer). 10 nm thick Hf0.5Zr0.5O2 thin films are deposited and annealed with or without the TiN capping layer with subsequent annealing at different time and temperature. Arrhenius plot is constructed to obtain the activation energy for the tetragonal‐to‐monoclinic phase transformation by calculating the amount of the transformed phase using X‐ray diffraction pattern. Johnson–Mehl–Avrami and nucleation‐limited transformation models are utilized to describe the characteristic nucleation and growth time and calculate the activation energy for the monoclinic phase transformation of the Hf0.5Zr0.5O2 thin film. Both models demonstrate that the TiN capping layer provides a kinetic energy barrier for tetragonal‐to‐monoclinic phase transformation and enhances the ferroelectric property.

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Section: Resultsmentioning

confidence: 99%

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf_0.5Zr_0.5O₂ Thin Films

Lee

Hyun

Kim

et al. 2018

Adv Elect Materials

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“…Besides the commonly used TiN, various capping layer materials have been studied, such as Pt, 51 RuO2, 52 TaN, 40 and Ir/IrO x . 53,54 In particular, using Ir/ IrO x as electrodes has successfully solved the long-standing fatigue issue of PZT 55 and is therefore of great interest to be applied to HfO 2 -based devices. However, in the case of Si: HfO 2 thin films, the Ir capped capacitor exhibited 13-14% lower P r than the TiN capped capacitor, which was attributed to different thermal expansion coefficients and the potential scavenging effect of TiN.…”

Section: Origins Of Ferroelectricity In Hfo 2 -Based Materialsmentioning

confidence: 99%

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

2016

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Ferroelectric random access memory (FeRAM) based on conventional ferroelectric perovskites, such as Pb(Zr,Ti)O 3 and SrBi 2 Ta 2 O 9 , has encountered bottlenecks on memory density and cost, because those conventional perovskites suffer from various issues mainly including poor complementary metal-oxide-semiconductor (CMOS)-compatibility and limited scalability. Nextgeneration cost-efficient, high-density FeRAM shall therefore rely on a material revolution. Since the discovery of ferroelectricity in Si:HfO 2 thin films in 2011, HfO 2 -based materials have aroused widespread interest in the field of FeRAM, because they are CMOScompatible and can exhibit robust ferroelectricity even when the film thickness is scaled down to below 10 nm. A review on this new class of ferroelectric materials is therefore of great interest. In this paper, the most appealing topics about ferroelectric HfO 2 -based materials including origins of ferroelectricity, advantageous material properties, and current and potential applications in FeRAM, are briefly reviewed.

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“…24 In their reports, the magnitude of the shift depended on the annealing temperature and time. 24 On the other hand, the P-E loop shifts in the authors' previous reports were in the range of B0.05-0.2 MV cm À1 into the positive bias direction. [10][11][12]14,15 These reports showed that the sign and magnitude of E int can be varied by various factors, including electrode materials, detailed deposition process, and annealing conditions for the ferroelectric films.…”

Section: Introductionmentioning

confidence: 97%

“…21 The films can be deposited using various deposition techniques, e.g. atomic layer deposition (ALD), [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]22 RF magnetron sputtering, 23 chemical vapor deposition (CVD), 24 and chemical solution deposition (CSD). 25 Among these techniques, the ALD is considered to be ideal for depositing the conformal and uniform films on nano-structured templates because of their characteristic self-saturating mechanism.…”

Section: Introductionmentioning

confidence: 99%

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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Study on the effect of heat treatment conditions on metalorganic-chemical-vapor-deposited ferroelectric Hf_0.5Zr_0.5O₂thin film on Ir electrode

Cited by 66 publications

References 31 publications

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf_0.5Zr_0.5O₂ Thin Films

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf_0.5Zr_0.5O₂ Thin Films

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

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

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Study on the effect of heat treatment conditions on metalorganic-chemical-vapor-deposited ferroelectric Hf0.5Zr0.5O2thin film on Ir electrode

Cited by 66 publications

References 31 publications

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf0.5Zr0.5O2 Thin Films

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf0.5Zr0.5O2 Thin Films

Ferroelectric HfO2-based materials for next-generation ferroelectric memories

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

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Study on the effect of heat treatment conditions on metalorganic-chemical-vapor-deposited ferroelectric Hf_0.5Zr_0.5O₂thin film on Ir electrode

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf_0.5Zr_0.5O₂ Thin Films

Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf_0.5Zr_0.5O₂ Thin Films

Ferroelectric HfO₂-based materials for next-generation ferroelectric memories

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