Proximity-Induced Ferroelectric Switching in Wurtzite/Fluorite Bilayers for High-Performance Ferroelectric Field-Effect Transistor.

Kim, Kyung Do; Yeom, Min Kyu; Park, Han Sol; Jeon, Gwangsik; Hwang, Cheol Seong · Adv Mater · 2025

basic_science · Level V

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Abstract

Proximity ferroelectricity, wherein polarization switching in one ferroelectric layer with a lower energy barrier can trigger switching in an adjacent ferroelectric with a higher energy barrier, has been demonstrated only in bilayers composed of structurally similar wurtzite-structured materials. This work demonstrates proximity-induced ferroelectric switching across a heterostructure composed of crystallographically and functionally dissimilar materials, wurtzite-structured AlScN and fluorite-structured HfZrO<sub>2</sub>. The AlScN/HfZrO<sub>2</sub> and AlN/HfZrO<sub>2</sub> bilayers exhibit cooperative switching dynamics despite their contrasting symmetry and polarization behaviors. This interfacial coupling produces a unique ferroelectric response, characterized by low remanent polarization and a high coercive field. Using the AlN/HfZrO<sub>2</sub> bilayer, a ferroelectric field-effect transistor is fabricated on a p-type Si substrate with phosphorus-doped source and drain regions. The device shows a wide memory window with excellent retention and endurance. These results establish a versatile materials design strategy for engineering ferroelectricity via structural and functional heterogeneity.