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Ferroelectric Al1−xScxN has raised much interest in recent years due to its unique ferroelectric properties and complementary metal oxide semiconductor back-end-of-line compatible processing temperatures. Potential applications in embedded nonvolatile memory, however, require ferroelectric materials to switch at relatively low voltages. One approach to achieving a lower switching voltage is to significantly reduce the Al1−xScxN thickness. In this work, ferroelectric behavior in 5–27 nm films of sputter deposited Al0.72Sc0.28N has been studied. We find that the 10 kHz normalized coercive field increases from 4.4 to 7.3 MV/cm when reducing the film thickness from 27.1 to 5.4 nm, while over the same thickness range, the characteristic breakdown field of a 12.5 μm radius capacitor increases from 8.3 to 12.1 MV/cm. The 5.4 nm film demonstrates ferroelectric switching at 5.5 V when excited with a 500 ns pulse and a switching speed of 60 ns.
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This content will become publicly available on August 25, 2026
Characterization of ferroelectric switching in 43 nm Y-36 lithium niobate films
Lithium niobate (LN) is a promising ferroelectric material used for emerging memories and radio frequency (RF) micromechanical resonators. The ferroelectric behavior of the bulk properties of LN has been well studied, and investigations on thin films have shown promising performance. However, the macroscopic ferroelectric properties of LN films that are sub-100 nm thick, which are desired to truly harness the advantages and scalability of the material, have not been explored. Here, we report the ferroelectric properties of 43 nm ultra-thin films of Y-36 LN sandwiched between two metal electrodes. Y-36 is a particularly promising cut for RF microacoustics, but can also be employed for integrated memories and photonics. Switching occurred with an average positive coercive field (+Ec) of 0.92 MV cm−1 and an average −Ec of 0.39 MV cm−1, resulting in the ability to switch the film polarization with < 2 V. The 43 nm film maintains a large positive remanent polarization (+PR) of 58 μC·cm−2 and a -PR of 55 μC·cm−2. The thin film shows excellent endurance, maintaining a stable PR value after 1 billion polarization switching cycles. Retention characteristics also show stable PR value after 100 s. Additionally, findings indicate a power series relationship of Ec∝ Fβ with β value at 0.253 and 0.053 for +Ec and −Ec, respectively. Overall, the characterization of these ultra-thin films of LN showcase its potential for miniaturization and application to tunable RF acoustics or emerging memories.
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- Award ID(s):
- 2104142
- PAR ID:
- 10651493
- Publisher / Repository:
- AIP publishing
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 127
- Issue:
- 8
- ISSN:
- 0003-6951
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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