Reactive sputtering of ferroelectric AlScN films with H2 gas flow for endurance improvement

The impact of H2 gas flow in the reactive sputtering process to 60 nm-thick ferroelectric Al1−xScxN films is investigated with x of 0.26 (high-Sc) and 0.12 (low-Sc). Al1−xScxN films exhibit clear ferroelectric switching, confirming the robustness against reducing ambient. The dielectric constants (ε...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 2024-03, Vol.63 (3), p.03SP45
Main Authors: Chen, Si-Meng, Hoshii, Takuya, Wakabayashi, Hitoshi, Tsutsui, Kazuo, Chang, Edward Yi, Kakushima, Kuniyuki
Format: Article
Language:English
Subjects:
AlScN
Coercivity
Endurance
Ferroelectric materials
Ferroelectricity
Gas flow
III-N ferroelectric
Leakage current
oxygen impurities
reactive sputtering
Sputtering
Switching
Thick films
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Summary:The impact of H2 gas flow in the reactive sputtering process to 60 nm-thick ferroelectric Al1−xScxN films is investigated with x of 0.26 (high-Sc) and 0.12 (low-Sc). Al1−xScxN films exhibit clear ferroelectric switching, confirming the robustness against reducing ambient. The dielectric constants (εi) as well as the leakage current decrease, and the breakdown field (EBD) increases with H2 flow. Although the remanent polarization (Pr) decreases with H2 flow, the wake-up effect is suppressed for the high-Sc film, and the fatigue effect is weakened for the low-Sc film. By probing the change in the coercive field (Ec) after the switching cycle test, we anticipate oxygen impurities bonded to Sc and Al atoms are the source of wake-up and fatigue effects, respectively. As a result, a high endurance cycle of 2 × 107 times was achieved for low-Sc films with H2 flow.
ISSN:0021-4922
1347-4065
DOI:10.35848/1347-4065/ad21bd