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De A, Jung MH, Kim YH, Bae SB, Jeong SG, Oh JY, Choi Y, Lee H, Kim Y, Choi T, Kim YM, Yang SM, Jeong HY, Choi WS. Symmetry Engineering of Epitaxial Hf 0.5Zr 0.5O 2 Ultrathin Films. ACS APPLIED MATERIALS & INTERFACES 2024; 16:27532-27540. [PMID: 38743018 DOI: 10.1021/acsami.4c03146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Robust ferroelectricity in HfO2-based ultrathin films has the potential to revolutionize nonvolatile memory applications in nanoscale electronic devices because of their compatibility with the existing Si technology. However, to fully exploit the potential of ferroelectric HfO2-based thin films, it is crucial to develop strategies for the controlled stabilization of various HfO2-based polymorphs in nanoscale heterostructures. This study demonstrates how substrate-orientation-induced anisotropic strain can engineer the crystal symmetry, structural domain morphology, and growth orientation of ultrathin Hf0.5Zr0.5O2 (HZO) films. Epitaxial ultrathin HZO films were grown on the heterostructures of (001)- and (110)-oriented La2/3Sr1/3MnO3/SrTiO3 (LSMO/STO) substrate. Various structural analyses revealed that the (110)-oriented substrate promotes a higher degree of structural order (crystallinity) with improved stability of the (111)-oriented orthorhombic phase (Pca21) of HZO. Conversely, the (001)-oriented substrate not only induces a distorted orthorhombic structure but also facilitates the partial stabilization of nonpolar phases. Electrical measurements revealed robust ferroelectric properties in epitaxial thin films without any wake-up effect, where the well-ordered crystal symmetry stabilized by STO(110) facilitated better ferroelectric characteristics. This study suggests that tuning the epitaxial growth of ferroelectric HZO through substrate orientation can improve the stability of the metastable ferroelectric orthorhombic phase and thereby offer a better understanding of device applications.
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Affiliation(s)
- Arnab De
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Min-Hyoung Jung
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Young-Hoon Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seong Bin Bae
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Seung Gyo Jeong
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jin Young Oh
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yeongju Choi
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hojin Lee
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea
| | - Yunseok Kim
- School of Advanced Materials and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Taekjib Choi
- Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sang Mo Yang
- Department of Physics, Sogang University, Seoul 04107, Republic of Korea
| | - Hu Young Jeong
- Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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Do HB, Luc QH, Pham PV, Phan-Gia AV, Nguyen TS, Le HM, De Souza MM. Metal-Induced Trap States: The Roles of Interface and Border Traps in HfO 2/InGaAs. MICROMACHINES 2023; 14:1606. [PMID: 37630142 PMCID: PMC10456933 DOI: 10.3390/mi14081606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/01/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023]
Abstract
By combining capacitance-voltage measurements, TCAD simulations, and X-ray photoelectron spectroscopy, the impact of the work function of the gate metals Ti, Mo, Pd, and Ni on the defects in bulk HfO2 and at the HfO2/InGaAs interfaces are studied. The oxidation at Ti/HfO2 is found to create the highest density of interface and border traps, while a stable interface at the Mo/HfO2 interface leads to the smallest density of traps in our sample. The extracted values of Dit of 1.27 × 1011 eV-1cm-2 for acceptor-like traps and 3.81 × 1011 eV-1cm-2 for donor-like traps are the lowest reported to date. The density and lifetimes of border traps in HfO2 are examined using the Heiman function and strongly affect the hysteresis of capacitance-voltage curves. The results help systematically guide the choice of gate metal for InGaAs.
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Affiliation(s)
- Huy-Binh Do
- Faculty of Applied Science, Ho Chi Minh City University of Technology and Education, 01 Vo Van Ngan Street, Ho Chi Minh City 700000, Vietnam
| | - Quang-Ho Luc
- Department of Materials Science and Engineering, National Yang Ming Chiao Tung University, 1001, Daxue Road, East District, Hsinchu 300093, Taiwan
| | - Phuong V. Pham
- Department of Physics, National Sun Yat-sen University, Kaohsiung 80424, Taiwan
| | - Anh-Vu Phan-Gia
- Faculty of Applied Science, Ho Chi Minh City University of Technology and Education, 01 Vo Van Ngan Street, Ho Chi Minh City 700000, Vietnam
| | - Thanh-Son Nguyen
- Faculty of Fundamental Sciences, University of Architecture Ho Chi Minh City, 196 Pasteur St., Dist. 3, Ho Chi Minh City 700000, Vietnam
| | - Hoang-Minh Le
- Faculty of electrical and electronics engineering, Ho Chi Minh City University of Technology and Education, 01 Vo Van Ngan Street, Ho Chi Minh City 700000, Vietnam
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Liao J, Dai S, Peng RC, Yang J, Zeng B, Liao M, Zhou Y. HfO 2-based ferroelectric thin film and memory device applications in the post-Moore era: A review. FUNDAMENTAL RESEARCH 2023; 3:332-345. [PMID: 38933762 PMCID: PMC11197553 DOI: 10.1016/j.fmre.2023.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 02/11/2023] [Accepted: 02/23/2023] [Indexed: 03/05/2023] Open
Abstract
The rapid development of 5G, big data, and Internet of Things (IoT) technologies is urgently required for novel non-volatile memory devices with low power consumption, fast read/write speed, and high reliability, which are crucial for high-performance computing. Ferroelectric memory has undergone extensive investigation as a viable alternative for commercial applications since the post-Moore era. However, conventional perovskite-structure ferroelectrics (e.g., PbZr x Ti1- x O3) encounter severe limitations for high-density integration owing to the size effect of ferroelectricity and incompatibility with complementary metal-oxide-semiconductor technology. Since 2011, the ferroelectric field has been primarily focused on HfO2-based ferroelectric thin films owing to their exceptional scalability. Several reviews discussing the control of ferroelectricity and device applications exist. It is believed that a comprehensive understanding of mechanisms based on industrial requirements and concerns is necessary, such as the wake-up effect and fatigue mechanism. These mechanisms reflect the atomic structures of the materials as well as the device physics. Herein, a review focusing on phase stability and domain structure is presented. In addition, the recent progress in related ferroelectric memory devices and their challenges is briefly discussed.
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Affiliation(s)
- Jiajia Liao
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China
- Frontier Research Center of Thin Films and Coatings for Device Applications, Academy of Advanced Interdisciplinary Research, Xidian University, Xi'an 710126, China
| | - Siwei Dai
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China
| | - Ren-Ci Peng
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China
- Frontier Research Center of Thin Films and Coatings for Device Applications, Academy of Advanced Interdisciplinary Research, Xidian University, Xi'an 710126, China
| | - Jiangheng Yang
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China
| | - Binjian Zeng
- Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China
| | - Min Liao
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China
- Frontier Research Center of Thin Films and Coatings for Device Applications, Academy of Advanced Interdisciplinary Research, Xidian University, Xi'an 710126, China
| | - Yichun Zhou
- School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710126, China
- Frontier Research Center of Thin Films and Coatings for Device Applications, Academy of Advanced Interdisciplinary Research, Xidian University, Xi'an 710126, China
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Cao Y, Zhang W, Li Y. Hafnium-doped zirconia ferroelectric thin films with excellent endurance at high polarization. NANOSCALE 2023; 15:1392-1401. [PMID: 36594335 DOI: 10.1039/d2nr05678j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Using thermal atomic layer deposition and subsequent rapid thermal annealing without the need for metal clamping atop, a remanent polarization (Pr) of 25.5 μC cm-2 was achieved in a 10 nm-thick ZrO2 film deposited on a W bottom electrode. Hafnium doping was further explored to improve the ferroelectric properties in Pr as well as the endurance of zirconia-based thin films. A significantly enhanced Pr reaching 41 μC cm-2 was obtained for 10 nm-thick hafnium-doped ZrO2 with an optimal Zr : Hf ratio of 3 : 1. Importantly, owing to the greatly reduced leakage, the optimal hafnium-doped ZrO2 thin films exhibited superior retention and outstanding endurance performances at relatively high polarizations, free of serious degradation for up to 2.3 × 109-6.8 × 109 field cycles at an initial Pr of 27 μC cm-2 and were even capable of over 107 cycles at a maximum Pr of 41 μC cm-2. The superb ferroelectricities were demonstrated on big-sized capacitors as well as sub-micrometer ones, isolated or in array. This would empower zirconia-based ferroelectric thin films as a competitive front-runner for practical applications in ferroelectric-related nanoelectronics.
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Affiliation(s)
- Yating Cao
- College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China.
| | - Wei Zhang
- College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China.
| | - Yubao Li
- College of Physics Science and Technology, Hebei University, Baoding 071002, P. R. China.
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Kingra SK, Parmar V, Suri M. In-Memory Computation Based Mapping of Keccak-f Hash Function. FRONTIERS IN NANOTECHNOLOGY 2022. [DOI: 10.3389/fnano.2022.841756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cryptographic hash functions play a central role in data security for applications such as message authentication, data verification, and detecting malicious or illegal modification of data. However, such functions typically require intensive computations with high volume of memory accesses. Novel computing architectures such as logic-in-memory (LIM)/in-memory computing (IMC) have been investigated in the literature to address the limitations of intense compute and memory bottleneck. In this work, we present an implementation of Keccak-f (a state-of-the-art secure hash algorithm) using a variant of simultaneous logic-in-memory (SLIM) that utilizes emerging non-volatile memory (NVM) devices. Detailed operation and instruction mapping on SLIM-based digital gates is presented. Through simulations, we benchmark the proposed approach using LIM cells based on four different emerging NVM devices (OxRAM, CBRAM, PCM, and FeRAM). The proposed mapping strategy when used with state-of-the-art emerging NVM devices offers EDP savings of up to 300× compared to conventional methods.
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