Structural and ferroelectric properties of Pr doped HfO2 thin films fabricated by chemical solution method

Liu, Heng; Zheng, Shuaizhi; Chen, Qiang; Zeng, Binjian; Jiang, Jie; Peng, Qiangxiang; Liao, Min; Zhou, Yue

doi:10.1007/s10854-019-00874-4

Cited by 34 publications

(32 citation statements)

References 54 publications

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“…Figure b compares experimental pattern with a simulated one for a density of 9.6 g cm − 2 , as expected for a monoclinic phase with 5 cat% of La. Such lower densities appear to be a common issue for CSD of HfO 2 and ZrO 2 judging from SEM, transmission electron microscopy, or atomic force microscopy images and from fewer cases of reported XRR results …”

mentioning

confidence: 54%

Toward Thick Piezoelectric HfO₂‐Based Films

Schenk

Godard

Mahjoub

et al. 2019

Physica Rapid Research Ltrs

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For HfO2‐based films, which are mainly prepared by atomic layer deposition, the desired ferroelectric (FE) properties typically vanish while extending the thickness beyond a limit of about 50 nm. Herein, the successful fabrication of a 1 μm‐thick piezoelectric La:HfO2 film is demonstrated using chemical solution deposition, paving the way toward sensor and actuator applications. After identifying the optimal La content, the film thickness is increased from 45 nm to 1 μm. Polarization and strain measurements evidence the persistence of the FE properties at all thicknesses and even a slight improvement due to a better orientation of the polar axis at higher thicknesses. Scanning electron microscopy and X‐ray reflectivity reveal a fine‐grained microstructure and a density of only 80% of the theoretical value, which seems to be a common issue of solution‐deposited HfO2‐based films, based on the performed literature survey. Using tilt‐angle‐dependent X‐ray diffraction scans, homogeneous nucleation is found to be the likely root cause of the observed microstructure. It is suggested that this microstructure issue is key for the optimization of cycling stability of solution‐based films to exploit the full potential of the HfO2 for cost‐efficient, thick piezoelectric films.

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mentioning

confidence: 54%

Toward Thick Piezoelectric HfO₂‐Based Films

Schenk

Godard

Mahjoub

et al. 2019

Physica Rapid Research Ltrs

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“…The cross‐sectional HRTEM image shown in Figure 2b and the fast Fourier transform (FFT) image (Figure 2c) of the sample reveals the interplanar distance as 2.93 Å, which corresponds to the d‐spacing of the (111) plane of the orthorhombic phase. [ 19,25–28 ] The atomic force microscopy (AFM) and HAADF‐STEM images of 7 × 4N film are presented in Figure S1, Supporting Information. A comparison of XRD patterns and crystallinity among the samples prepared by varying the number of deposited layers and annealing is presented in the supporting information (Figures S2 and S3, Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Multi‐Step Chemical Solution Deposition‐Annealing Process Toward Wake‐Up Free Ferroelectricity in Y:HfO₂ Films

Samanta

Anoop

Joh

et al. 2021

Adv Materials Inter

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Ferroelectricity in HfO2 thin films can be utilized for fast, power‐efficient, and highly scalable non‐volatile memories. However, the required wake‐up process for inducing ferroelectricity/ achieving higher polarization is one of the major hurdles that hinder HfO2‐based thin films from developing reliable electronic devices. The wake‐up effect is believed to originate from i) phase transformation from non‐ferroelectric to ferroelectric, ii) movement of defect entities (mainly oxygen vacancy defects) near the film‐electrode interface, and iii) heterogeneity of the electrode interfaces. In the present study, an experimental strategy is designed to overcome these sources of the wake‐up process. A multi‐step deposition and annealing process is carried out to induce wake‐up‐free ferroelectricity in Yttrium doped HfO2 (Y:HfO2) thin film directly grown on Si‐substrate. Furnace annealing is utilized instead of the standard rapid thermal annealing process to reduce the oxygen deficiencies and stimulate the direct growth of the polar Y:HfO2. The oxygen‐vacancy‐related defects are found to be the dominating source of wake‐up effect in Y‐doped HfO2 films. The step‐wise deposition and annealing in the oxygen atmosphere facilitate direct growth of the polar phase, reduce the oxygen vacancies, and induce wake‐up‐free ferroelectricity in Y:HfO2.

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“…The inset of the areas marked by a red rectangle in Fig. 2(c) was the fast fourier transformation (FFT) diffractogram, which certifies the orthorhombic phase (111) plane with an interplanar distance of 2.90 Å, implying the formation of ferroelectric phase [21][22]. Moreover, (111) plane of TiN with an interplanar distance of 2.06 Å which corresponds to (111)oriented plane of TiN was discovered at the interface between HfO2 (ferroelectric phase) and TiN.…”

Section: Resuits and Disscussionsmentioning

confidence: 96%

Impact of Radiation Effect on Ferroelectric Al-Doped HfO₂ Metal-Ferroelectric- Insulator-Semiconductor Structure

et al. 2020

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The γ-ray total dose radiation effects on ferroelectric Al-doped HfO2 (HfAlO) thin films with an n-type Si substrate were studied. The I-V, P-V, C-V and fatigue characteristics of the HfAlO-based Metal-Ferroelectric-Insulator-Semiconductor (MFIS) structure were analyzed with the increasing total dose from 0 to 1 Mrad (Si). The remnant polarization (Pr) values, the capacitance (C) values and the switching voltage (Vc) of this MFIS gate structure decreased with the increasing total dose. A TCAD model of Metal/HfAlO/SiO2/Si (MFIS) was proposed to explain the degradation mechanism of ferroelectric properties of the MFIS structure. We find that the new interface defects caused by radiation can reduce the electric field strength with the increasing total dose, which can significantly influence the irradiation properties of the HfAlO/SiO2/n-Si gate structure. These results provide the basis to applications for the HfO2-based devices in radiation working environment.

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Structural and ferroelectric properties of Pr doped HfO2 thin films fabricated by chemical solution method

Cited by 34 publications

References 54 publications

Toward Thick Piezoelectric HfO₂‐Based Films

Toward Thick Piezoelectric HfO₂‐Based Films

Multi‐Step Chemical Solution Deposition‐Annealing Process Toward Wake‐Up Free Ferroelectricity in Y:HfO₂ Films

Impact of Radiation Effect on Ferroelectric Al-Doped HfO₂ Metal-Ferroelectric- Insulator-Semiconductor Structure

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Structural and ferroelectric properties of Pr doped HfO2 thin films fabricated by chemical solution method

Cited by 34 publications

References 54 publications

Toward Thick Piezoelectric HfO2‐Based Films

Toward Thick Piezoelectric HfO2‐Based Films

Multi‐Step Chemical Solution Deposition‐Annealing Process Toward Wake‐Up Free Ferroelectricity in Y:HfO2 Films

Impact of Radiation Effect on Ferroelectric Al-Doped HfO2 Metal-Ferroelectric- Insulator-Semiconductor Structure

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Toward Thick Piezoelectric HfO₂‐Based Films

Toward Thick Piezoelectric HfO₂‐Based Films

Multi‐Step Chemical Solution Deposition‐Annealing Process Toward Wake‐Up Free Ferroelectricity in Y:HfO₂ Films

Impact of Radiation Effect on Ferroelectric Al-Doped HfO₂ Metal-Ferroelectric- Insulator-Semiconductor Structure