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Kim JY, Choi MJ, Lee YJ, Park SH, Choi S, Baek JH, Im IH, Kim SJ, Jang HW. High-Performance Ferroelectric Thin Film Transistors with Large Memory Window Using Epitaxial Yttrium-Doped Hafnium Zirconium Gate Oxide. ACS APPLIED MATERIALS & INTERFACES 2024; 16:19057-19067. [PMID: 38564293 DOI: 10.1021/acsami.3c16427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Preventing ferroelectric materials from losing their ferroelectricity over a low thickness of several nanometers is crucial in developing multifunctional nanoelectronics. Epitaxially grown 5 at. % yttrium-doped Hf0.5Zr0.5O2 (YHZO) thin films exhibit an atomically smooth surface, an ability to maintain ferroelectricity even at a thickness of 10 nm, and excellent insulating properties, making them suitable for use as gate oxides in ferroelectric thin film transistors (FeTFTs). Through the epitaxial growth of a YHZO/La0.67Sr0.33MnO3 (LSMO)/SrTiO3 (STO) heterostructure, YHZO effectively retains its ferroelectricity and orthorhombic single phase, leading to enhancing electron mobility (∼19.74 cm2 V-1 s-1) and memory window (3.7 V) in the amorphous InGaZnO4 (a-IGZO)/YHZO/LSMO/STO FeTFTs. These FeTFTs demonstrate a consistent memory function with remarkable endurance (∼106 cycles) and retention (∼104 s). Furthermore, they sustain a constant memory window even under ±6 V bias stress for 104 s and exhibit excellent stability even under ±6 V/1 ms pulse cycling for 107 cycles. For comparison, a transistor with the same structure was fabricated using epitaxial nonferroelectric LaAlO3 (LAO) and epitaxial undoped Hf0.5Zr0.5O2 (HZO) as alternatives to YHZO. This study presents a novel approach to exploit the potential of YHZO in FeTFTs, contributing to the development of next-generation logic-in-memory.
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Affiliation(s)
- Jae Young Kim
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Min-Ju Choi
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Yoon Jung Lee
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Sung Hyuk Park
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Sungkyun Choi
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji Hyun Baek
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - In Hyuk Im
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Seung Ju Kim
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
| | - Ho Won Jang
- Department of Materials Science and Engineering Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea
- Advanced Institute of Convergence Technology, Seoul National University, Suwon 16229, Republic of Korea
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Chuang C, Wang T, Chou C, Yi S, Jiang Y, Shyue J, Chen M. Sharp Transformation across Morphotropic Phase Boundary in Sub-6 nm Wake-Up-Free Ferroelectric Films by Atomic Layer Technology. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2302770. [PMID: 37759405 PMCID: PMC10646279 DOI: 10.1002/advs.202302770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 09/12/2023] [Indexed: 09/29/2023]
Abstract
Atomic layer engineering is investigated to tailor the morphotropic phase boundary (MPB) between antiferroelectric, ferroelectric, and paraelectric phases. By increasing the HfO2 seeding layer with only 2 monolayers, the overlying ZrO2 layer experiences the dramatic phase transition across the MPB. Conspicuous ferroelectric properties including record-high remanent polarization (2Pr ≈ 60 µC cm-2 ), wake-up-free operation, and high compatibility with advanced semiconductor technology nodes, are achieved in the sub-6 nm thin film. The prominent antiferroelectric to ferroelectric phase transformation is ascribed to the in-plane tensile stress introduced into ZrO2 by the HfO2 seeding layer. Based on the high-resolution and high-contrast images of surface grains extracted precisely by helium ion microscopy, the evolution of the MPB between tetragonal, orthorhombic, and monoclinic phases with grain size is demonstrated for the first time. The result indicates that a decrease in the average grain size drives the crystallization from the tetragonal to polar orthorhombic phases.
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Affiliation(s)
- Chun‐Ho Chuang
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei10617Taiwan
| | - Ting‐Yun Wang
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei10617Taiwan
| | - Chun‐Yi Chou
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei10617Taiwan
| | - Sheng‐Han Yi
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei10617Taiwan
| | - Yu‐Sen Jiang
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei10617Taiwan
| | - Jing‐Jong Shyue
- Research Center for Applied SciencesAcademia SinicaTaipei11529Taiwan
| | - Miin‐Jang Chen
- Department of Materials Science and EngineeringNational Taiwan UniversityTaipei10617Taiwan
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3
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Banerjee D, Dey CC, Kumar R, Modak B, Hazra S, Datta S, Ghosh B, Thakare SV, Jha SN, Bhattacharyya D. Comprehensive study on the origin of orthorhombic phase stabilization in Gd-doped HfO 2 and DFT calculations. Phys Chem Chem Phys 2023; 25:21479-21491. [PMID: 37539659 DOI: 10.1039/d3cp00062a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/05/2023]
Abstract
In recent times, ultra-thin films of hafnium oxide (HfO2) have shown ferroelectricity (FE) attributed to the orthorhombic (o) phase of HfO2 with space group Pca21. This polar o-phase could be stabilized in the doped thin film of the oxide. In the present work, both polar and non-polar o-phases of HfO2 could be stabilized in Gd-doped bulk polycrystalline HfO2. Rietveld analysis of XRD data shows that the relative population of o-phases in the presence of the monoclinic (m) phase of HfO2 increases with increasing Gd-content. The local environment around the host atom has been investigated by time differential perturbed angular correlation (TDPAC) spectroscopy, synchrotron based X-ray near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) measurements. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) measurements showed a reduction in grain size with increasing Gd-dopant indicating a solute drag effect. It could be established that the segregation of the Gd-dopant in the grain boundary is a thermodynamically favorable process and the solute drag effect plays an important role in nucleation of the o-phase in bulk HfO2. Stabilization of Gd in both Pbca and Pca21 phases of HfO2 was supported by defect formation energy calculations using density functional theory (DFT). The present study has important implications in future applications of HfO2 in ferroelectric devices and in understanding the role of dopants in stabilizing the o-phase of HfO2 in the bulk.
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Affiliation(s)
- D Banerjee
- Radiochemistry Division (BARC), Variable Energy Cyclotron Centre, Kolkata 700064, India.
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - C C Dey
- Applied Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata 700064, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Ravi Kumar
- Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - Brindaban Modak
- Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India
| | - Snehamoyee Hazra
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, JD Block, Sector-III, Salt Lake City, Kolkata 700106, India
| | - Subarna Datta
- Material Science Section, Physics Group, Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata 700064, India
| | - Barnali Ghosh
- Department of Condensed Matter and Materials Physics, S. N. Bose National Centre for Basic Sciences, JD Block, Sector-III, Salt Lake City, Kolkata 700106, India
| | - S V Thakare
- Radiopharmaceutical Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - S N Jha
- Beamline Development and Application Section, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - D Bhattacharyya
- Atomic & Molecular Physics Division, Bhabha Atomic Research Centre, Mumbai 400085, India
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Shi S, Xi H, Cao T, Lin W, Liu Z, Niu J, Lan D, Zhou C, Cao J, Su H, Zhao T, Yang P, Zhu Y, Yan X, Tsymbal EY, Tian H, Chen J. Interface-engineered ferroelectricity of epitaxial Hf 0.5Zr 0.5O 2 thin films. Nat Commun 2023; 14:1780. [PMID: 36997572 PMCID: PMC10063548 DOI: 10.1038/s41467-023-37560-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 03/22/2023] [Indexed: 04/01/2023] Open
Abstract
Ferroelectric hafnia-based thin films have attracted intense attention due to their compatibility with complementary metal-oxide-semiconductor technology. However, the ferroelectric orthorhombic phase is thermodynamically metastable. Various efforts have been made to stabilize the ferroelectric orthorhombic phase of hafnia-based films such as controlling the growth kinetics and mechanical confinement. Here, we demonstrate a key interface engineering strategy to stabilize and enhance the ferroelectric orthorhombic phase of the Hf0.5Zr0.5O2 thin film by deliberately controlling the termination of the bottom La0.67Sr0.33MnO3 layer. We find that the Hf0.5Zr0.5O2 films on the MnO2-terminated La0.67Sr0.33MnO3 have more ferroelectric orthorhombic phase than those on the LaSrO-terminated La0.67Sr0.33MnO3, while with no wake-up effect. Even though the Hf0.5Zr0.5O2 thickness is as thin as 1.5 nm, the clear ferroelectric orthorhombic (111) orientation is observed on the MnO2 termination. Our transmission electron microscopy characterization and theoretical modelling reveal that reconstruction at the Hf0.5Zr0.5O2/ La0.67Sr0.33MnO3 interface and hole doping of the Hf0.5Zr0.5O2 layer resulting from the MnO2 interface termination are responsible for the stabilization of the metastable ferroelectric phase of Hf0.5Zr0.5O2. We anticipate that these results will inspire further studies of interface-engineered hafnia-based systems.
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Affiliation(s)
- Shu Shi
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore
| | - Haolong Xi
- School of Materials and Energy, Electron Microscopy Centre of Lanzhou University and Key Laboratory of Magnetism and Magnetic Materials of the Ministry of Education, Lanzhou University, Lanzhou, 730000, PR China
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Tengfei Cao
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588-0299, USA
| | - Weinan Lin
- Department of physics, Xiamen University, Xiamen, 361005, China
| | - Zhongran Liu
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China
| | - Jiangzhen Niu
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, Hebei University, Baoding, 071002, PR China
| | - Da Lan
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore
| | - Chenghang Zhou
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore
| | - Jing Cao
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), 138634, Singapore, Singapore
| | - Hanxin Su
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore
| | - Tieyang Zhao
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore
| | - Ping Yang
- Singapore Synchrotron Light Source (SSLS), National University of Singapore, 5 Research Link, 117603, Singapore, Singapore
| | - Yao Zhu
- Institute of Microelectronics, Agency for Science, Technology and Research (A*STAR), 138634, Singapore, Singapore
| | - Xiaobing Yan
- Key Laboratory of Brain-Like Neuromorphic Devices and Systems of Hebei Province, Hebei University, Baoding, 071002, PR China.
| | - Evgeny Y Tsymbal
- Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE, 68588-0299, USA.
| | - He Tian
- Center of Electron Microscope, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
- School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, 450052, China.
| | - Jingsheng Chen
- Department of Materials Science and Engineering, National University of Singapore, 117575, Singapore, Singapore.
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Highly-scaled and fully-integrated 3-dimensional ferroelectric transistor array for hardware implementation of neural networks. Nat Commun 2023; 14:504. [PMID: 36720868 PMCID: PMC9889761 DOI: 10.1038/s41467-023-36270-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 01/20/2023] [Indexed: 02/02/2023] Open
Abstract
Hardware-based neural networks (NNs) can provide a significant breakthrough in artificial intelligence applications due to their ability to extract features from unstructured data and learn from them. However, realizing complex NN models remains challenging because different tasks, such as feature extraction and classification, should be performed at different memory elements and arrays. This further increases the required number of memory arrays and chip size. Here, we propose a three-dimensional ferroelectric NAND (3D FeNAND) array for the area-efficient hardware implementation of NNs. Vector-matrix multiplication is successfully demonstrated using the integrated 3D FeNAND arrays, and excellent pattern classification is achieved. By allocating each array of vertical layers in 3D FeNAND as the hidden layer of NN, each layer can be used to perform different tasks, and the classification of color-mixed patterns is achieved. This work provides a practical strategy to realize high-performance and highly efficient NN systems by stacking computation components vertically.
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Cüppers F, Hirai K, Funakubo H. On the switching dynamics of epitaxial ferroelectric CeO 2-HfO 2 thin film capacitors. NANO CONVERGENCE 2022; 9:56. [PMID: 36515821 PMCID: PMC9751238 DOI: 10.1186/s40580-022-00344-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Epitaxial layers of ferroelectric orthorhombic HfO2 are frequently investigated as model systems for industrially more relevant polycrystalline films. The recent success in stabilizing the orthorhombic phase in the solid-solution cerium oxide - hafnium oxide system allows detailed investigations of external influences during fabrication. This report analyzes the ferroelectric properties of two thin film capacitors, which were post-deposition annealed in N2 and O2 atmospheres to achieve the orthorhombic phase after room temperature deposition. The samples, which exhibit very similar constituent phase, appear identical in conventional polarization-field hysteresis measurements. However, a significant switching speed difference is observed in pristine devices. Continued field cycling reduces the difference. Deeper analysis of switching transients based on the Nucleation Limited Switching model suggests that the O2 heat treatment atmosphere results in an altered oxygen vacancy profile, which is reverted during ferroelectric cycling.
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Affiliation(s)
- Felix Cüppers
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 226-8502, Yokohama, Japan.
- PGI-10, Forschungszentrum Jülich GmbH, Jülich, Germany.
| | - Koji Hirai
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 226-8502, Yokohama, Japan
| | - Hiroshi Funakubo
- Department of Materials Science and Engineering, Tokyo Institute of Technology, 226-8502, Yokohama, Japan.
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Banerjee W, Kashir A, Kamba S. Hafnium Oxide (HfO 2 ) - A Multifunctional Oxide: A Review on the Prospect and Challenges of Hafnium Oxide in Resistive Switching and Ferroelectric Memories. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107575. [PMID: 35510954 DOI: 10.1002/smll.202107575] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/24/2022] [Indexed: 06/14/2023]
Abstract
Hafnium oxide (HfO2 ) is one of the mature high-k dielectrics that has been standing strong in the memory arena over the last two decades. Its dielectric properties have been researched rigorously for the development of flash memory devices. In this review, the application of HfO2 in two main emerging nonvolatile memory technologies is surveyed, namely resistive random access memory and ferroelectric memory. How the properties of HfO2 equip the former to achieve superlative performance with high-speed reliable switching, excellent endurance, and retention is discussed. The parameters to control HfO2 domains are further discussed, which can unleash the ferroelectric properties in memory applications. Finally, the prospect of HfO2 materials in emerging applications, such as high-density memory and neuromorphic devices are examined, and the various challenges of HfO2 -based resistive random access memory and ferroelectric memory devices are addressed with a future outlook.
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Affiliation(s)
- Writam Banerjee
- Center for Single Atom-based Semiconductor Device, Department of Material Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Alireza Kashir
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, Prague 8, 182 21, Czech Republic
| | - Stanislav Kamba
- Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, Prague 8, 182 21, Czech Republic
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Ali F, Abbas A, Wu G, Daaim M, Akhtar A, Kim KH, Yang B. Novel Fluorite-Structured Materials for Solid-State Refrigeration. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2200133. [PMID: 35445535 DOI: 10.1002/smll.202200133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Refrigeration based on the electrocaloric effect can offer many advantages over conventional cooling technologies in terms of efficiency, size, weight, and power source. The discovery of ferroelectric and antiferroelectric properties in fluorite-based materials in 2011 has led to diverse applications related to memory (e.g., ferroelectric tunnel junctions, nonvolatile memory, and field-effect transistors) and energy fields (e.g., energy storage and harvesting, electrocaloric refrigeration, and infrared detection). Fluorite-based materials exhibit several properties not shared by most conventional materials (such as in terms of compatibility with complementary metal-oxide semiconductors and 3D nanostructures, deposition thickness at the nanometer scale, and simple composition). Here, the electrocaloric refrigeration properties of fluorite-based ferroelectric/antiferroelectric materials are reviewed by focusing on the advantages of ZrO2 - and HfO2 -based materials (e.g., relative to conventional perovskite- and polymer-based counterparts). Finally, the recent progress made in this research field are also discussed along with its future perspectives.
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Affiliation(s)
- Faizan Ali
- School of Information and Intelligence Engineering, University of Sanya, Sanya, 572022, P. R. China
- Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Akmal Abbas
- Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Guoyi Wu
- Institute of Earthquake Engineering, Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian, Liaoning, 116024, China
| | - Muhammad Daaim
- Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Materials Science and Engineering, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Awais Akhtar
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, 999077, China
| | - Ki-Hyun Kim
- Department of Civil and Environmental Engineering, Hanyang University, 222 Wangsimni-Ro, Seoul, 04763, Republic of Korea
| | - Boxiong Yang
- School of Information and Intelligence Engineering, University of Sanya, Sanya, 572022, P. R. China
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Song T, Tan H, Estandía S, Gàzquez J, Gich M, Dix N, Fina I, Sánchez F. Improved polarization and endurance in ferroelectric Hf 0.5Zr 0.5O 2 films on SrTiO 3(110). NANOSCALE 2022; 14:2337-2343. [PMID: 35088065 DOI: 10.1039/d1nr06983g] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The metastable orthorhombic phase of Hf0.5Zr0.5O2 (HZO) can be stabilized in thin films on La0.67Sr0.33MnO3 (LSMO) buffered (001)-oriented SrTiO3 (STO) by intriguing epitaxy that results in (111)-HZO oriented growth and robust ferroelectric properties. Here, we show that the orthorhombic phase can also be epitaxially stabilized on LSMO/STO(110), presenting the same out-of-plane (111) orientation but a different distribution of the in-plane crystalline domains. The remanent polarization of HZO films with a thickness of less than 7 nm on LSMO/STO(110) is 33 μC cm-3, which corresponds to a 50% improvement over equivalent films on LSMO/STO(001). Furthermore, HZO on LSMO/STO(110) presents higher endurance, switchable polarization is still observed up to 4 × 1010 cycles, and retention of more than 10 years. These results demonstrate that tuning the epitaxial growth of ferroelectric HfO2, here using STO(110) substrates, allows the improvement of functional properties of relevance for memory applications.
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Affiliation(s)
- Tingfeng Song
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Huan Tan
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Saúl Estandía
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Jaume Gàzquez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Martí Gich
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Nico Dix
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Ignasi Fina
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
| | - Florencio Sánchez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra 08193, Barcelona, Spain.
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Yadav M, Kashir A, Oh S, Nikam RD, Kim H, Jang H, Hwang H. High polarization and wake-up free ferroelectric characteristics in ultrathin Hf 0.5Zr 0.5O 2devices by control of oxygen-deficient layer. NANOTECHNOLOGY 2021; 33:085206. [PMID: 34787101 DOI: 10.1088/1361-6528/ac3a38] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/16/2021] [Indexed: 06/13/2023]
Abstract
The formation of an interfacial layer is believed to affect the ferroelectric properties in HfO2based ferroelectric devices. The atomic layer deposited devices continue suffering from a poor bottom interfacial condition, since the formation of bottom interface is severely affected by atomic layer deposition and annealing process. Herein, the formation of bottom interfacial layer was controlled through deposition of different bottom electrodes (BE) in device structure W/HZO/BE. The transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy analyses done on devices W/HZO/W and W/HZO/IrOxsuggest the strong effect of IrOxin controlling bottom interfacial layer formation while W/HZO/W badly suffers from interfacial layer formation. W/HZO/IrOxdevices show high remnant polarization (2Pr) ∼ 53μC cm-2, wake-up free endurance cycling characteristics, low leakage current with demonstration of low annealing temperature requirement as low as 350 °C, valuable for back-end-of-line integration. Further, sub-5 nm HZO thicknesses-based W/HZO/IrOxdevices demonstrate high 2Prand wake-up free ferroelectric characteristics, which can be promising for low power and high-density memory applications. 2.2 nm, 3 nm, and 4 nm HZO based W/HZO/IrOxdevices show 2Prvalues 13.54, 22.4, 38.23μC cm-2at 4 MV cm-1and 19.96, 30.17, 48.34μC cm-2at 5 MV cm-1, respectively, with demonstration of wake-up free ferroelectric characteristics.
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Affiliation(s)
- Manoj Yadav
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
| | - Alireza Kashir
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
- Institute of Physics ASCR, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - Seungyeol Oh
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
| | - Revannath Dnyandeo Nikam
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
| | - Hyungwoo Kim
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
| | - Hojung Jang
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
| | - Hyunsang Hwang
- Centre for Single Atom-Based Semiconductor Device and Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 790784, Republic of Korea
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Song T, Tan H, Bachelet R, Saint-Girons G, Fina I, Sánchez F. Impact of La Concentration on Ferroelectricity of La-Doped HfO 2 Epitaxial Thin Films. ACS APPLIED ELECTRONIC MATERIALS 2021; 3:4809-4816. [PMID: 34841249 PMCID: PMC8613842 DOI: 10.1021/acsaelm.1c00672] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
Epitaxial thin films of HfO2 doped with La have been grown on SrTiO3(001) and Si(001), and the impact of the La concentration on the stabilization of the ferroelectric phase has been determined. Films with 2-5 at. % La doping present the least amount of paraelectric monoclinic and cubic phases and exhibit the highest polarization, having a remanent polarization above 20 μC/cm2. The dopant concentration results in an important effect on the coercive field, which is reduced with increasing La content. Combined high polarization, high retention, and high endurance of at least 1010 cycles is obtained in 5 at. % La-doped films.
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Affiliation(s)
- Tingfeng Song
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Huan Tan
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Romain Bachelet
- Univ.
Lyon, Ecole Centrale de Lyon, INSA Lyon, CPE Lyon, CNRS, Institut
des Nanotechnologies de Lyon - INL, UMR5270, Université Claude Bernard Lyon 1, 69134 Ecully, France
| | - Guillaume Saint-Girons
- Univ.
Lyon, Ecole Centrale de Lyon, INSA Lyon, CPE Lyon, CNRS, Institut
des Nanotechnologies de Lyon - INL, UMR5270, Université Claude Bernard Lyon 1, 69134 Ecully, France
| | - Ignasi Fina
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain
| | - Florencio Sánchez
- Institut
de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, Bellaterra, 08193 Barcelona, Spain
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Chouprik A, Negrov D, Tsymbal EY, Zenkevich A. Defects in ferroelectric HfO 2. NANOSCALE 2021; 13:11635-11678. [PMID: 34190282 DOI: 10.1039/d1nr01260f] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The discovery of ferroelectricity in polycrystalline thin films of doped HfO2 has reignited the expectations of developing competitive ferroelectric non-volatile memory devices. To date, it is widely accepted that the performance of HfO2-based ferroelectric devices during their life cycle is critically dependent on the presence of point defects as well as structural phase polymorphism, which mainly originates from defects either. The purpose of this review article is to overview the impact of defects in ferroelectric HfO2 on its functional properties and the resulting performance of memory devices. Starting from the brief summary of defects in classical perovskite ferroelectrics, we then introduce the known types of point defects in dielectric HfO2 thin films. Further, we discuss main analytical techniques used to characterize the concentration and distribution of defects in doped ferroelectric HfO2 thin films as well as at their interfaces with electrodes. The main part of the review is devoted to the recent experimental studies reporting the impact of defects in ferroelectric HfO2 structures on the performance of different memory devices. We end up with the summary and perspectives of HfO2-based ferroelectric competitive non-volatile memory devices.
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Affiliation(s)
- Anastasia Chouprik
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow region, Russia.
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13
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Wang Z, Hur J, Tasneem N, Chern W, Yu S, Khan A. Extraction of Preisach model parameters for fluorite-structure ferroelectrics and antiferroelectrics. Sci Rep 2021; 11:12474. [PMID: 34127695 PMCID: PMC8203701 DOI: 10.1038/s41598-021-91492-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 05/25/2021] [Indexed: 11/09/2022] Open
Abstract
Flourite-structure ferroelectrics (FEs) and antiferroelectrics (AFEs) such as HfO2 and its variants have gained copious attention from the semiconductor community, because they enable complementary metal-oxide-semiconductor (CMOS)-compatible platforms for high-density, high-performance non-volatile and volatile memory technologies. While many individual experiments have been conducted to characterize and understand fluorite-structure FEs and AFEs, there has been little effort to aggregate the information needed to benchmark and provide insights into their properties. We present a fast and robust modeling framework that automatically fits the Preisach model to the experimental polarization (\documentclass[12pt]{minimal}
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\begin{document}$$Q_{FE}$$\end{document}QFE) versus electric field (\documentclass[12pt]{minimal}
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\begin{document}$$E_{FE}$$\end{document}EFE) hysteresis characterizations of fluorite-structure FEs. The modifications to the original Preisach model allow the double hysteresis loops in fluorite-structure antiferroelectrics to be captured as well. By fitting the measured data reported in the literature, we observe that ferroelectric polarization and dielectric constant decrease as the coercive field rises in general.
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Affiliation(s)
- Zheng Wang
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, 30332, USA.
| | - Jae Hur
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, 30332, USA
| | - Nujhat Tasneem
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, 30332, USA
| | - Winston Chern
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, 02142, USA.,Izentis LLC, PO Box 397002, Cambridge, MA, 02139, USA
| | - Shimeng Yu
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, 30332, USA
| | - Asif Khan
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, 30332, USA.,Georgia Institute of Technology, School of Materials Science and Engineering, Atlanta, 30332, USA
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14
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Influence of Applied Stress on the Ferroelectricity of Thin Zr-Doped HfO2 Films. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11094295] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
HfO2-based ferroelectric materials have been widely studied for their application in ferroelectric FETs, which are compatible with conventional CMOS processes; however, problems with the material’s inherent fatigue properties have limited its potential for device application. This paper systematically investigates the effects of tensile stress and annealing temperature on the endurance and ferroelectric properties faced by Zr-doped HfO2 ferroelectric film. The remnant polarization (Pr) shows an increasing trend with annealing temperature, while the change in the coercive electric field (Ec) is not obvious in terms of the relationship with tensile stress or annealing temperature. In addition, the application of tensile stress does help to improve the endurance characteristics by about two orders of magnitude for the ferroelectric material, and the endurance properties show a tendency to be negatively correlated with annealing temperature. Overall, although the effect of stress on the ferroelectricity of a HZO material is not obvious, it has a great influence on its endurance properties and can optimize the endurance of the material, and ferroelectricity exhibits a higher dependence on temperature. The optimization of the endurance properties of HZO materials by stress can facilitate their development and application in future integrated circuit technology.
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Banerjee D, Dey CC, Kumar R, Sewak R, Jha SN, Bhattacharyya D, Acharya R, Pujari PK. Probing the solute-drag effect and its role in stabilizing the orthorhombic phase in bulk La-doped HfO 2 by X-ray and gamma ray spectroscopy. Phys Chem Chem Phys 2021; 23:16258-16267. [PMID: 34309608 DOI: 10.1039/d1cp00096a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The recent observation of ferroelectricity in ultra thin films of hafnium oxide (HfO2) has been attributed to the orthorhombic (o) phase of HfO2 with space group Pca21. Although this oxide is polymorphic in nature, this polar o-phase is known to be stabilized in the doped thin film oxide. The objective of the present experiment is to stabilize the o-phases in La doped bulk polycrystalline HfO2 and investigate their evolution with the doping concentration through Time Differential Perturbed Angular Correlation (TDPAC), X-ray Absorption Near Edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) measurements. The present work reports the presence of both the polar Pca21 phase and the antipolar Pbca phase at different La-concentrations. Two o-phases of HfO2 with space groups Pca21 and Pbca, difficult to distinguish by other complimentary methods, could be unambiguously identified by utilizing the atomic scale sensitivity of the electric field gradient (EFG) embedded in TDPAC spectroscopy. The determination of the oxidation state and the local environment of La-atoms by XANES and EXAFS measurements illuminates the microscopic role of the dopant in stabilizing the o-phase. The "solute drag model" proposes a critical crystallite size for the nucleation of the o-phase in bulk HfO2 and explains the role of the La-dopant in stabilizing the o-phase. Thus the present study shows the possibility of stabilizing the polar o-phase and hence attaining ferroelectricity in bulk HfO2 to augment the scope of future application for this ferroelectric device.
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Affiliation(s)
- D Banerjee
- Radiochemistry Laboratory, RCD (BARC), Variable Energy Cyclotron Centre, 1/AF Bidhannagar, Kolkata 700064, India.
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