Communication Dans Un Congrès Année : 2025

Enhancing Polarization and Reliability in HZO-Based FTJs Using WOx Electrodes and Interfacial Layers

Résumé

HfO₂-based ferroelectric devices have gained significant attention due to their excellent scalability and compatibility with CMOS processes, making them promising for future memory and logic technologies. While Atomic Layer Deposition is currently the most widely used method for fabricating these devices, this study explores Radio-Frequency sputtering as an alternative, owing to its low carbon contamination, industrial relevance, and the advantage of room-temperature deposition [1]. TiN is commonly used as an electrode in HfO₂-based devices because it facilitates the stabilization of the orthorhombic phase, which is essential for ferroelectricity [2]. However, part of this stabilization arises from oxygen vacancies induced by TiN’s oxygen scavenging behaviour [3]. While beneficial to some extent, excessive oxygen deficiency can introduce point defects and negatively impact device reliability— especially in ferroelectric tunnel junctions (FTJs), where direct tunnelling is the desired conduction mechanism. To mitigate this issue, we investigate the use of a WOₓ-based electrode or interfacial layer that acts as an oxygen reservoir [4], compensating for the oxygen vacancies caused by TiN. Various device structures were fabricated using a ferroelectric Hf0.5Zr0.5O2(HZO) layer, incorporating different sequences of rapid thermal annealing, to study its impact on ferroelectric properties, structure, chemistry, and interfacial states of HZO devices. Initial electrical measurements showed promising ferroelectric characteristics, with a 2Pr value of 40 μC/cm² in films thinner than 6 nm, indicating suitability for tunnelling studies. Structural characterization using X-ray diffraction was performed to identify phase composition, while X-ray photoelectron spectroscopy was used to analyse chemical states and interfacial behaviour. Electrical characterizations were carried out to further evaluate polarization performance and overall device behaviour. These findings offer valuable insights into optimizing sputtered HZO devices for reliable FTJ applications and present a foundation for developing artificial synapses in neuromorphic computing systems. References : [1] Bouaziz, J., et al. (2019) APL Materials, 7(8). [2] Schroeder, U., et al. (2022). Nature Reviews Materials, 7(8), 653-669. [3] Hamouda, W., et al. (2020). Journal of Applied Physics, 127(6). [4] Wang, X., et al. (2024). Advanced Electronic Materials, 10(6), 2300798

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Dates et versions

hal-05279432 , version 1 (23-09-2025)

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  • HAL Id : hal-05279432 , version 1

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Anjana Thomas, Alexandre Boyer, Akash Mhase, Bertrand Vilquin, Jordan Bouaziz, et al.. Enhancing Polarization and Reliability in HZO-Based FTJs Using WOx Electrodes and Interfacial Layers. South Asia Ferroelectric Symposium (SAFS), IEEE UFFC, Aug 2025, Bengaluru (Bangalore), India. ⟨hal-05279432⟩
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