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Journal of Advanced Ceramics 2024, 13(3): 282-292 https://doi.org/10.26599/JAC.2024.9220852
Research Article | Open Access | Issue | Published: 13 March 2024

Depolarization mitigated in ferroelectric Hf0.5Zr0.5O2 ultrathin films (< 5 nm) on Si substrate by interface engineering

Show Author's Information Se Hyun Kim1,†,  Younghwan Lee2,†,  Dong Hyun Lee1,†,  Geun Hyeong Park1,  Hyun Woo Jeong1,  Kun Yang1,  Yong Hyeon Cho1,  Young Yong Kim4,  Min Hyuk Park1,2,3( )
Department of Materials Science and Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
Research Institute of Advanced Materials, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
Inter-university Semiconductor Research Center, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
Pohang Accelerator Laboratory, Pohang University of Science & Technology, Pohang 790784, Republic of Korea

† Se Hyun Kim, Younghwan Lee, and Dong Hyun Lee contributed equally to this work.

Keywords:
ferroelectric, charge trapping, hafnia, depolarization
Cite this article:
Kim SH, Lee Y, Lee DH, et al. Depolarization mitigated in ferroelectric Hf0.5Zr0.5O2 ultrathin films (< 5 nm) on Si substrate by interface engineering. Journal of Advanced Ceramics, 2024, 13(3): 282-292. https://doi.org/10.26599/JAC.2024.9220852
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Abstract Full text Electronic supplementary material About this article

(Hf,Zr)O2 offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the nanoscale. However, scaling this material to sub-5 nm thickness poses several challenges, including the formation of an interfacial layer and high trap concentration. In particular, a low-k SiO2 interfacial layer is naturally formed when (Hf,Zr)O2 films are directly grown on a Si substrate, leading to high depolarization fields and rapid reduction of the remanent polarization. To address these issues, we conducted a study to significantly improve ferroelectricity and switching endurance of (Hf,Zr)O2 films with sub-5 nm thicknesses by inserting a TiO2 interfacial layer. The deposition of a Ti film prior to Hf0.5Zr0.5O2 film deposition resulted in a high-k TiO2 interfacial layer and prevented the direct contact of Hf0.5Zr0.5O2 with Si. Our findings show that the high-k TiO2 interfacial layer can reduce the SiO2/Si interface trap density and the depolarization field, resulting in a switchable polarization of 60.2 μC/cm2 for a 5 nm thick Hf0.5Zr0.5O2 film. Therefore, we propose that inserting a high-k TiO2 interfacial layer between the Hf0.5Zr0.5O2 film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of (Hf,Zr)O2 grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.


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Electronic supplementary material
About this article

Depolarization mitigated in ferroelectric Hf0.5Zr0.5O2 ultrathin films (< 5 nm) on Si substrate by interface engineering

Show Author's information Se Hyun Kim1,†, Younghwan Lee2,†, Dong Hyun Lee1,†, Geun Hyeong Park1, Hyun Woo Jeong1, Kun Yang1, Yong Hyeon Cho1, Young Yong Kim4, Min Hyuk Park1,2,3( )
Department of Materials Science and Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
Research Institute of Advanced Materials, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
Inter-university Semiconductor Research Center, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
Pohang Accelerator Laboratory, Pohang University of Science & Technology, Pohang 790784, Republic of Korea

† Se Hyun Kim, Younghwan Lee, and Dong Hyun Lee contributed equally to this work.

Abstract

(Hf,Zr)O2 offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the nanoscale. However, scaling this material to sub-5 nm thickness poses several challenges, including the formation of an interfacial layer and high trap concentration. In particular, a low-k SiO2 interfacial layer is naturally formed when (Hf,Zr)O2 films are directly grown on a Si substrate, leading to high depolarization fields and rapid reduction of the remanent polarization. To address these issues, we conducted a study to significantly improve ferroelectricity and switching endurance of (Hf,Zr)O2 films with sub-5 nm thicknesses by inserting a TiO2 interfacial layer. The deposition of a Ti film prior to Hf0.5Zr0.5O2 film deposition resulted in a high-k TiO2 interfacial layer and prevented the direct contact of Hf0.5Zr0.5O2 with Si. Our findings show that the high-k TiO2 interfacial layer can reduce the SiO2/Si interface trap density and the depolarization field, resulting in a switchable polarization of 60.2 μC/cm2 for a 5 nm thick Hf0.5Zr0.5O2 film. Therefore, we propose that inserting a high-k TiO2 interfacial layer between the Hf0.5Zr0.5O2 film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of (Hf,Zr)O2 grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

Keywords: ferroelectric, charge trapping, hafnia, depolarization

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Received: 29 April 2023
Revised: 20 December 2023
Accepted: 16 January 2024
Published: 13 March 2024
Issue date: March 2024

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© The Author(s) 2024.

Acknowledgements

Acknowledgements

This study was supported by the National Research Foundation (NRF) grant, funded by the Ministry of Science and Information and Communication Technology of Korea (MSIT) (Nos. 2022M3F3A2A01073562, 2020R1C1C1008193, and 2021M3F3A2A02037889). Younghwan Lee acknowledges support from the NRF grant, funded by the MSIT (No. NRF-2022R1A6A3A01086832). We would like to thank Editage (www.editage.co.kr) for editing and reviewing the English language in the manuscript. Experiments at PLS-II were supported in part by the Korean government MSIT and POSTECH.

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