Coercive Field Reduction in Ultra-thin Al1-XScXN via Interfacial Engineering with a Scandium Electrode

Fuente: arXiv
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Main Authors: Zhang, Yinuo, Rai, Rajeev Kumar, Esteves, Giovanni, Wang, Yubo, Jariwala, Deep M., Stach, Eric A., Olsson III, Roy H.
Format: Preprint
Published: 2025
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author Zhang, Yinuo
Rai, Rajeev Kumar
Esteves, Giovanni
Wang, Yubo
Jariwala, Deep M.
Stach, Eric A.
Olsson III, Roy H.
author_facet Zhang, Yinuo
Rai, Rajeev Kumar
Esteves, Giovanni
Wang, Yubo
Jariwala, Deep M.
Stach, Eric A.
Olsson III, Roy H.
contents Aluminum scandium nitride (AlScN) ferroelectrics are promising for next-generation non-volatile memory applications due to high remnant polarization compared with Pb(ZrxTi1-x)O3 and doped-HfO2 material systems, as well as their fast switching and scalability to nanometer thicknesses. As AlScN films are thinned to 10 nm thickness, coercive field has been shown to substantially increase, which hinders low voltage operation. We demonstrate that interfacial engineering through bottom electrode selection and strain management reduces this coercive field increase with scaling and improves ferroelectric performance. Here, we demonstrate robust ferroelectricity in ultra-thin AlScN capacitors deposited on a Sc bottom electrode under both alternating current and direct current conditions. The coercive field is reduced by over 20 percent compared to capacitors with an Al bottom electrode. Furthermore, the difference in dynamic switching behavior over a decade of frequency was evaluated by applying the KAI model. At frequencies lower than 16.7 kHz, the capacitors with Sc and Al bottom electrodes exhibit comparable KAI exponents of 0.030 and 0.028, indicating similar switching kinetics. However, at higher frequencies, the capacitor with an Al bottom electrode shows a significantly higher exponent of 0.063, indicating a stronger frequency dependence, whereas the capacitor with a Sc bottom electrode maintains a stable exponent of 0.030, suggesting a lower frequency dependence during faster switching scenarios. The Scanning Electron Nanobeam Diffraction technique was selected to measure the strain difference in AlScN thin films grown on templates with different lattice mismatch, providing a correlation between lattice mismatch, film strain and switching behavior in ultra-thin film systems.
format Preprint
id arxiv_https___arxiv_org_abs_2506_10169
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Coercive Field Reduction in Ultra-thin Al1-XScXN via Interfacial Engineering with a Scandium Electrode
Zhang, Yinuo
Rai, Rajeev Kumar
Esteves, Giovanni
Wang, Yubo
Jariwala, Deep M.
Stach, Eric A.
Olsson III, Roy H.
Materials Science
Applied Physics
Aluminum scandium nitride (AlScN) ferroelectrics are promising for next-generation non-volatile memory applications due to high remnant polarization compared with Pb(ZrxTi1-x)O3 and doped-HfO2 material systems, as well as their fast switching and scalability to nanometer thicknesses. As AlScN films are thinned to 10 nm thickness, coercive field has been shown to substantially increase, which hinders low voltage operation. We demonstrate that interfacial engineering through bottom electrode selection and strain management reduces this coercive field increase with scaling and improves ferroelectric performance. Here, we demonstrate robust ferroelectricity in ultra-thin AlScN capacitors deposited on a Sc bottom electrode under both alternating current and direct current conditions. The coercive field is reduced by over 20 percent compared to capacitors with an Al bottom electrode. Furthermore, the difference in dynamic switching behavior over a decade of frequency was evaluated by applying the KAI model. At frequencies lower than 16.7 kHz, the capacitors with Sc and Al bottom electrodes exhibit comparable KAI exponents of 0.030 and 0.028, indicating similar switching kinetics. However, at higher frequencies, the capacitor with an Al bottom electrode shows a significantly higher exponent of 0.063, indicating a stronger frequency dependence, whereas the capacitor with a Sc bottom electrode maintains a stable exponent of 0.030, suggesting a lower frequency dependence during faster switching scenarios. The Scanning Electron Nanobeam Diffraction technique was selected to measure the strain difference in AlScN thin films grown on templates with different lattice mismatch, providing a correlation between lattice mismatch, film strain and switching behavior in ultra-thin film systems.
title Coercive Field Reduction in Ultra-thin Al1-XScXN via Interfacial Engineering with a Scandium Electrode
topic Materials Science
Applied Physics
url https://arxiv.org/abs/2506.10169