| Autor: |
Zefu Zhao, Yun-Wen Chen, Yu-Rui Chen, C. W. Liu |
| Jazyk: |
angličtina |
| Rok vydání: |
2024 |
| Předmět: |
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| Zdroj: |
IEEE Access, Vol 12, Pp 71598-71605 (2024) |
| Druh dokumentu: |
article |
| ISSN: |
2169-3536 |
| DOI: |
10.1109/ACCESS.2024.3402120 |
| Popis: |
Metal-Ferroelectric-Metal (MFM) devices possessing high remanent polarizations ( $2P_{r}$ ) of 84 and $73~\mu $ C/cm2 are demonstrated with nearly epitaxially grown Hf0.5Zr0.5O2 (HZO) films on (001) n+-Si(3E19/cm $^{3}$ ) and n+-Ge(3E20/cm $^{3}$ ) substrates, respectively, which are higher than MFM devices with HZO films grown on amorphous SiO2 and partially crystallized TiN underlayers/substrates. The HZO superlattice films by sequential ZrO2/HfO2 plasma-enhanced atomic layer deposition (PEALD) process show high crystallinity in TEM images of all devices; however, the measured $2P_{r}$ values are quite different, ranging from 84 to $33\mu $ C/cm2. The high-resolution scanning transmission electron microscopy (HR-STEM) images of HZO films on n+-Si and n+-Ge show the polarization axis of o-phase is well-aligned with the growth direction which is consistent with observed high $2P_{r}$ values. Much lower interfacial energy at o-phase/Si(Ge) interfaces than m-(t-)phase/Si(Ge) by density functional theory (DFT) calculations indicates that o-phase is greatly stabilized in the HZO films on n+-Si(Ge) substrates. Strong $2P_{r}$ of 51 and $47~\mu $ C/cm2 are measured after 1E9 and 1E11 endurance cycles for HZO films on n+-Si and n+-Ge substrates, respectively. This study shows epitaxial ferroelectric HZO films could be achieved by using small misfit substrates with the thermal budget as low as 450°C. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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