| Autor: |
Jinseong Heo, Hyangsook Lee, Yeehyun Park, Yeonchoo Cho, Duk-Hyun Choe, Hyun Hwi Lee, Hyoungsub Kim, Seunghun Kang, Mirine Leem, Eunha Lee, Taehwan Moon, Jung-Hwa Kim, Sanghyun Jo, Yunseok Kim, Deokjoon Eom, Seontae Park, Hyun-Joon Shin |
| Rok vydání: |
2021 |
| Předmět: |
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| Zdroj: |
ACS applied materialsinterfaces. 13(30) |
| ISSN: |
1944-8252 |
| Popis: |
HfO2-based ferroelectrics are highly expected to lead the new paradigm of nanoelectronic devices owing to their unexpected ability to enhance ferroelectricity in the ultimate thickness scaling limit (≤2 nm). However, an understanding of its physical origin remains uncertain because its direct microstructural and chemical characterization in such a thickness regime is extremely challenging. Herein, we solve the mystery for the continuous retention of high ferroelectricity in an ultrathin hafnium zirconium oxide (HZO) film (∼2 nm) by unveiling the evolution of microstructures and crystallographic orientations using a combination of state-of-the-art structural analysis techniques beyond analytical limits and theoretical approaches. We demonstrate that the enhancement of ferroelectricity in ultrathin HZO films originates from textured grains with a preferred orientation along an unusual out-of-plane direction of (112). In principle, (112)-oriented grains can exhibit 62% greater net polarization than the randomly oriented grains observed in thicker samples (>4 nm). Our first-principles calculations prove that the hydroxyl adsorption during the deposition process can significantly reduce the surface energy of (112)-oriented films, thereby stabilizing the high-index facet of (112). This work provides new insights into the ultimate scaling of HfO2-based ferroelectrics, which may facilitate the design of future extremely small-scale logic and memory devices. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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