Huge Reduction of the Wake-Up Effect in Ferroelectric HZO Thin Films

Bouaziz, Jordan; Romeo, Pédro Rojo; Baboux, Nicolas; Vilquin, Bertrand

doi:10.1021/acsaelm.9b00367

Cited by 44 publications

(31 citation statements)

References 25 publications

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“…These defects can cause the wake‐up effect by pinning the ferroelectric domain walls. [ 24 ] The formation of the m‐phase was totally suppressed during RTA under the capping electrode confinement (not shown here). All films contained t‐ and o‐phases, possibly arising from the in‐plane tensile strain applied to the HZO film during thermal annealing.…”

Section: Resultsmentioning

confidence: 71%

“…[ 22,23 ] Therefore, the wake‐up effect can be substantially reduced by the reduction of m‐ and t‐phase during thin‐film processing. [ 24 ] Goh et al [ 25 ] evaluated the effect of metal oxide (as an electrode) on the wake‐up behavior of the Hf 0.5 Zr 0.5 O 2 (HZO) film and they observed an improve in wake‐up behavior which could be due to the suppression of oxygen vacancy at the interfacial region. Oxide metal electrode can provide additional oxygen to the HZO layer to hinder the oxygen vacancy generation during the application of the electric field.…”

Section: Introductionmentioning

confidence: 99%

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Defect Engineering to Achieve Wake‐up Free HfO₂‐Based Ferroelectrics

Kashir

Hwang

2020

Adv Eng Mater

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Wake‐up effect is still an obstacle in the commercialization of hafnia‐based ferroelectric thin films. Herein, the effect of defects, controlled by ozone dosage, on the field cycling behavior of the atomic layer deposited Hf0.5Zr0.5O2 (HZO) films is investigated. A nearly wake‐up free device is achieved after reduction of carbon contamination and oxygen defects by increasing the ozone dosage. The sample which is grown at 30 s ozone pulse duration shows about 97% of the woken‐up Pr at the pristine state whereas that grown below 5 s ozone pulse time shows a pinched hysteresis loop, that underwent a large wake‐up effect. This behavior is attributed to the increase in oxygen vacancy and carbon concentration in the films deposited at insufficient O3 dosage, which is confirmed by X‐ray photoelectron spectroscopy (XPS). The X‐ray diffraction (XRD) scan shows that the increase in ozone pulse time yields the reduction of tetragonal phase; therefore, the dielectric constant reduces. The I–V measurements reveal the increase in current density as the ozone dosage decreases, which might be due to the generation of oxygen vacancies in the deposited film. Finally, the dynamics of wake‐up effect is investigated, and it appears to be explained well by the Johnson–Mehl–Avrami–Kolmogoroff model, which is based on structural phase transformation.

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Section: Resultsmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Defect Engineering to Achieve Wake‐up Free HfO₂‐Based Ferroelectrics

Kashir

Hwang

2020

Adv Eng Mater

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“…The woken-up P-E loop obtained after 1000 cycles at 3 MV/cm from the sample annealed at 700 °C for 5 s showed a small change in the 2Pr value (Figure 3d), which indicates that the W/HZO/W ferroelectric device is almost wake-up free. The suppression of m-phase and the reduction of tphase revealed through XRD results (Figure 3b), due to a proper annealing condition might decrease the wake-up effect in HfO2-based thin film [45]. The endurance measurement using triangle waveform electric filed with the frequency of 100 Hz clearly indicates an almost wake-up free device until its break-down cycle (Figure 3e).…”

Section: Resultsmentioning

confidence: 94%

Large Remnant Polarization in a Wake-Up Free Hf_0.5Zr_0.5O₂ Ferroelectric Film through Bulk and Interface Engineering

Kashir

Kim

et al. 2021

ACS Appl. Electron. Mater.

105

135

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A wake-up free Hf0.5Zr0.5O2 (HZO) ferroelectric film with the highest remnant polarization (Pr) value to-date was achieved through tuning of the ozone pulse duration, the annealing process, and the metal/insulator interface. The ozone dosage during the atomic layer deposition of HZO films appears to be a crucial parameter in suppressing the mechanisms driving the wake-up effect. A tungsten capping electrode with a relatively low thermal expansion coefficient enables the induction of an in-plane tensile strain, which increases the formation of the orthorhombic phase while decreasing the formation of the monoclinic phase during the cooling step of the annealing process. Therefore, increasing the annealing temperature TA followed by rapid cooling to room temperature resulted in a substantial increase in the 2Pr value (≈ 64 µC/cm 2 ). However, the leakage current increased considerably, which can affect the performance of metal-insulator-metal (MIM) devices. To reduce the leakage current while maintaining the mechanical stress during thermal annealing, a 10 nm Pt layer was inserted between the W/HZO bottom interface. This resulted in a ~ 20-fold decrease in the leakage current while the 2Pr value remained almost constant (~ 60 µC/cm 2 ). The increase in barrier height at the Pt/HZO interface compared to that of the W/HZO interface coupled with the suppression of the formation of interfacial oxides (WOx) by the introduction of a Pt/HZO interface serves to decrease the leakage current.

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“…68 The authors proposed that the distinct Pnm21 phase would be the reason of the absence of wake-up effect in these epitaxial films. However, it has to be noted that wake-up effect is not a property genuine of a phase, [69][70][71] and different mechanisms can produce it. 3,[72][73][74][75] Assumptions of Qi et al, 68 which can be extended to the other authors reporting DFT calculations of ferroelectric HfO2 and other polymorphs, are based on strain states that differ to the experimental data revealed by XRD and STEM.…”

Section: Polar Phase Stabilized On Lsmomentioning

confidence: 99%

Epitaxial Ferroelectric HfO₂ Films: Growth, Properties, and Devices

Fina

Sánchez

2021

ACS Appl. Electron. Mater.

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About ten years after ferroelectricity was first reported in doped HfO2 polycrystalline films, there is tremendous interest in this material and ferroelectric oxides are once again in the spotlight of the memories industry. Great efforts are being made to understand and control ferroelectric properties. Epitaxial films, which have fewer defects and a more controlled microstructure than polycrystalline films, can be very useful for this purpose. Epitaxial films of ferroelectric HfO2 have been much less investigated, but after the first report in 2015 significant progress has been achieved. This review summarizes and discusses the main advances on epitaxial HfO2, considering growth, study of structural and ferroelectric properties, identification of the ferroelectric phase, and fabrication of devices. We hope this review will help to researchers investigating epitaxial HfO2. It can also help extend the interest of the ferroelectric HfO2 community, now basically focused on polycrystalline samples, to epitaxial films.

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Huge Reduction of the Wake-Up Effect in Ferroelectric HZO Thin Films

Cited by 44 publications

References 25 publications

Defect Engineering to Achieve Wake‐up Free HfO₂‐Based Ferroelectrics

Defect Engineering to Achieve Wake‐up Free HfO₂‐Based Ferroelectrics

Large Remnant Polarization in a Wake-Up Free Hf_0.5Zr_0.5O₂ Ferroelectric Film through Bulk and Interface Engineering

Epitaxial Ferroelectric HfO₂ Films: Growth, Properties, and Devices

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Huge Reduction of the Wake-Up Effect in Ferroelectric HZO Thin Films

Cited by 44 publications

References 25 publications

Defect Engineering to Achieve Wake‐up Free HfO2‐Based Ferroelectrics

Defect Engineering to Achieve Wake‐up Free HfO2‐Based Ferroelectrics

Large Remnant Polarization in a Wake-Up Free Hf0.5Zr0.5O2 Ferroelectric Film through Bulk and Interface Engineering

Epitaxial Ferroelectric HfO2 Films: Growth, Properties, and Devices

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Product

Resources

About

Defect Engineering to Achieve Wake‐up Free HfO₂‐Based Ferroelectrics

Defect Engineering to Achieve Wake‐up Free HfO₂‐Based Ferroelectrics

Large Remnant Polarization in a Wake-Up Free Hf_0.5Zr_0.5O₂ Ferroelectric Film through Bulk and Interface Engineering

Epitaxial Ferroelectric HfO₂ Films: Growth, Properties, and Devices