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| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2501.12616 |
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| _version_ | 1866913661041246208 |
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| author | Wang, Tiantian Zhang, He Xie, Yongjie Du, Subi Sheng, Da Liu, Zhaolong Wang, Sheng Li, Hui Zhang, Qinghua Wang, Kai Xu, Bing Qiu, Xianggang Xu, Yang Gu, Lin Chen, Xiaolong |
| author_facet | Wang, Tiantian Zhang, He Xie, Yongjie Du, Subi Sheng, Da Liu, Zhaolong Wang, Sheng Li, Hui Zhang, Qinghua Wang, Kai Xu, Bing Qiu, Xianggang Xu, Yang Gu, Lin Chen, Xiaolong |
| contents | Hafnium oxide (HfO2), particularly at low-dimensional scales, exhibits extensive promising applications in ultrahigh density devices like low-power logic and non-volatile memory devices due to its compatibility with current semiconductor technology1-5. However, achieving ferroelectricity (FE) at ultimate scale especially in undoped HfO2 remains challenging as the non-centrosymmetric FE phase, so-called O-III (space group: Pca21) is metastable and FE has a strong tendency of depolarization with the decrease in thickness6. Up to now, this phase has usually stabilized via doping with other elements7-9. But the minimum film thickness is still limited to 1 nm, about 2-unit-cell, to keep FE8. Thinner and undoped films, conducive to further miniature device size and avoid contamination during deposition process, have been a challenge to fabricate on Si substrates. Herein, we report the robust FE observed in undoped HfO2 ultrathin films directly grown on Si substrate via atomic layer deposition (ALD) and post-heat treat in vacuum. The so-fabricated ferroelectric O-III phase contains about 4.48 at% oxygen vacancy, is robust even monoclinic phase (space group: P21/c) coexists. The spontaneous and switchable polarization is remarkably stable, still surviving even in films down to 0.5 nm (one-unit-cell). Our results show the robust FE O-III phase can be obtained in films down to one-unit-cell in thickness on Si, providing a practical way to fabricating this important material in thickness limit. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_12616 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Ferroelectricity in undoped HfO2 down to one-unit-cell on Si substrate Wang, Tiantian Zhang, He Xie, Yongjie Du, Subi Sheng, Da Liu, Zhaolong Wang, Sheng Li, Hui Zhang, Qinghua Wang, Kai Xu, Bing Qiu, Xianggang Xu, Yang Gu, Lin Chen, Xiaolong Materials Science Other Condensed Matter Hafnium oxide (HfO2), particularly at low-dimensional scales, exhibits extensive promising applications in ultrahigh density devices like low-power logic and non-volatile memory devices due to its compatibility with current semiconductor technology1-5. However, achieving ferroelectricity (FE) at ultimate scale especially in undoped HfO2 remains challenging as the non-centrosymmetric FE phase, so-called O-III (space group: Pca21) is metastable and FE has a strong tendency of depolarization with the decrease in thickness6. Up to now, this phase has usually stabilized via doping with other elements7-9. But the minimum film thickness is still limited to 1 nm, about 2-unit-cell, to keep FE8. Thinner and undoped films, conducive to further miniature device size and avoid contamination during deposition process, have been a challenge to fabricate on Si substrates. Herein, we report the robust FE observed in undoped HfO2 ultrathin films directly grown on Si substrate via atomic layer deposition (ALD) and post-heat treat in vacuum. The so-fabricated ferroelectric O-III phase contains about 4.48 at% oxygen vacancy, is robust even monoclinic phase (space group: P21/c) coexists. The spontaneous and switchable polarization is remarkably stable, still surviving even in films down to 0.5 nm (one-unit-cell). Our results show the robust FE O-III phase can be obtained in films down to one-unit-cell in thickness on Si, providing a practical way to fabricating this important material in thickness limit. |
| title | Ferroelectricity in undoped HfO2 down to one-unit-cell on Si substrate |
| topic | Materials Science Other Condensed Matter |
| url | https://arxiv.org/abs/2501.12616 |