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Pujar P, Cho H, Kim YH, Zagni N, Oh J, Lee E, Gandla S, Nukala P, Kim YM, Alam MA, Kim S. An Aqueous Route to Oxygen-Deficient Wake-Up-Free La-Doped HfO 2 Ferroelectrics for Negative Capacitance Field Effect Transistors. ACS NANO 2023; 17:19076-19086. [PMID: 37772990 DOI: 10.1021/acsnano.3c04983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
The crucial role of nanocrystalline morphology in stabilizing the ferroelectric orthorhombic (o)-phase in doped-hafnia films is achieved via chemical solution deposition (CSD) by intentionally retaining carbonaceous impurities to inhibit grain growth. However, in the present study, large-grained (>100 nm) La-doped HfO2 (HLO) films are grown directly on silicon by adopting engineered water-diluted precursors with a minimum carbonaceous load and excellent shelf life. The o-phase stabilization is accomplished through a well-distributed La dopant, which generates uniformly populated oxygen vacancies, eliminating the need for oxygen-scavenging electrodes. These oxygen-deficient HLOs show a maximum remnant polarization of 37.6 μC/cm2 (2Pr) without wake-up and withstand large fields (>6.2 MV/cm). Furthermore, CSD-HLO in series with Al2O3 improves switching of MOSFETs (with an amorphous oxide channel) based on the negative capacitance effect. Thus, uniformly distributed oxygen vacancies serve as a standalone factor in stabilizing the o-phase, enabling efficient wake-up-free ferroelectricity without the need for nanostructuring, capping stresses, or oxygen-reactive electrodes.
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Affiliation(s)
- Pavan Pujar
- Department of Ceramic Engineering, Indian Institute of Technology (IIT-BHU), Varanasi, Uttar Pradesh 221005, India
| | - Haewon Cho
- Multifunctional Nano Bio Electronics Lab, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Gyeonggi-do, Republic of Korea
| | - Young-Hoon Kim
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Nicolò Zagni
- Department of Engineering "Enzo Ferrari" (DIEF), University of Modena and Reggio Emilia, Modena 41125, Italy
| | - Jeonghyeon Oh
- Multifunctional Nano Bio Electronics Lab, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Gyeonggi-do, Republic of Korea
| | - Eunha Lee
- Analytical Engineering Group, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics, Suwon 16678 Republic of Korea
| | - Srinivas Gandla
- Multifunctional Nano Bio Electronics Lab, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Gyeonggi-do, Republic of Korea
| | - Pavan Nukala
- Centre for Nano Science and Engineering, Indian Institute of Science, Bengaluru 560012, India
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Muhammad Ashraful Alam
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States
| | - Sunkook Kim
- Multifunctional Nano Bio Electronics Lab, School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Gyeonggi-do, Republic of Korea
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Kang S, Jang WS, Morozovska AN, Kwon O, Jin Y, Kim YH, Bae H, Wang C, Yang SH, Belianinov A, Randolph S, Eliseev EA, Collins L, Park Y, Jo S, Jung MH, Go KJ, Cho HW, Choi SY, Jang JH, Kim S, Jeong HY, Lee J, Ovchinnikova OS, Heo J, Kalinin SV, Kim YM, Kim Y. Highly enhanced ferroelectricity in HfO 2-based ferroelectric thin film by light ion bombardment. Science 2022; 376:731-738. [PMID: 35549417 DOI: 10.1126/science.abk3195] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Continuous advancement in nonvolatile and morphotropic beyond-Moore electronic devices requires integration of ferroelectric and semiconductor materials. The emergence of hafnium oxide (HfO2)-based ferroelectrics that are compatible with atomic-layer deposition has opened interesting and promising avenues of research. However, the origins of ferroelectricity and pathways to controlling it in HfO2 are still mysterious. We demonstrate that local helium (He) implantation can activate ferroelectricity in these materials. The possible competing mechanisms, including He ion-induced molar volume changes, vacancy redistribution, vacancy generation, and activation of vacancy mobility, are analyzed. These findings both reveal the origins of ferroelectricity in this system and open pathways for nanoengineered binary ferroelectrics.
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Affiliation(s)
- Seunghun Kang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Woo-Sung Jang
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Anna N Morozovska
- Institute of Physics, National Academy of Sciences of Ukraine, 46, Prospekt. Nauky, 03028 Kyiv, Ukraine
| | - Owoong Kwon
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Yeongrok Jin
- Department of Physics, Pusan National University, Busan 46241, Republic of Korea
| | - Young-Hoon Kim
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Hagyoul Bae
- Samsung Advanced Institute of Technology, Suwon 16678, Republic of Korea
| | - Chenxi Wang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Sang-Hyeok Yang
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Alex Belianinov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.,Sandia National Laboratories, Albuquerque, NM 87123, USA
| | - Steven Randolph
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Eugene A Eliseev
- Institute for Problems of Materials Science, National Academy of Sciences of Ukraine, Krjijanovskogo 3, 03142 Kyiv, Ukraine
| | - Liam Collins
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Yeehyun Park
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Sanghyun Jo
- Samsung Advanced Institute of Technology, Suwon 16678, Republic of Korea
| | - Min-Hyoung Jung
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Kyoung-June Go
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hae Won Cho
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Si-Young Choi
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Jae Hyuck Jang
- Center for Scientific Instrumentation, Korea Basic Science Institute (KBSI), Daejeon 34133, Republic of Korea
| | - Sunkook Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Hu Young Jeong
- Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Jaekwang Lee
- Department of Physics, Pusan National University, Busan 46241, Republic of Korea
| | - Olga S Ovchinnikova
- Computational Sciences and Engineering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jinseong Heo
- Samsung Advanced Institute of Technology, Suwon 16678, Republic of Korea
| | - Sergei V Kalinin
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.,Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37920, USA
| | - Young-Min Kim
- Department of Energy Science, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
| | - Yunseok Kim
- School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 16419, Republic of Korea
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Yamaguchi A, Nemoto T, Kurata H. Study of C K-Edge High Energy Resolution Energy-Loss Near-Edge Structures of Copper Phthalocyanine and Its Chlorinated Molecular Crystals by First-Principles Band Structure Calculations. J Phys Chem A 2020; 124:1735-1743. [PMID: 32040325 DOI: 10.1021/acs.jpca.9b10832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
High energy resolution energy-loss near-edge structures (ELNES) at the carbon K-edge of copper phthalocyanine (CuPc) and its chlorinated molecular crystals were observed using electron energy-loss spectroscopy combined with a scanning transmission electron microscope equipped with a monochromator. The ELNES spectra were investigated using first-principles band structure calculations with a core-hole introduced into the 1s orbitals of the nonequivalent C atoms. The calculated spectra including half a core-hole were consistent with the experimental spectra. The spectral features could be interpreted in terms of the different contributions of the partial density of states (PDOS) of nonequivalent C atoms with different transition energies depending on the site. The core-hole effects were also discussed using the spatial distribution of unoccupied states and PDOSs, which revealed site-dependent core-hole effects, where a C atom with a strong spatial distribution intensity of the unoccupied states in the ground state (GS) are susceptible to the core-hole effects. The spectral changes due to chlorination of the CuPc molecule were mainly attributed to an increase of the threshold energy of the C atoms bonded to chlorine, and the influence of the change in the PDOS by chlorination was not significantly large.
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Affiliation(s)
- Atsushi Yamaguchi
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Takashi Nemoto
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Hiroki Kurata
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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