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Lanthanum Oxide Surface Treatment to Form Diffusion Barrier and Interface Dipoles on Ferroelectric FET
Journal
IEEE Electron Device Letters
Author
Changyeon Kang, Sheung Hun Kim, Jun Hong Chu, Youngkeun Park, Gyusoup Lee, Seong Ho Kim, and Byung Jin Cho
Year
2024
Date
August, 2024

Abstract

 We propose a novel surface treatment tech-nique using a few La2O3 ALD cycles to improve the per-formance and reliability of FeFET-based non-volatile memory devices. The interfacial layer formed by a few La2O3 ALD cycles prior to the deposition of the HfZrO (HZO) ferroelectric layer on the silicon substrate, acts as a diffusion barrier, reducing the number of trap sites in the gate stack. The La2O3 interfacial layer also creates an im-print effect by forming interface dipoles between the HZO and Si. This reduces the switching voltage (Vsw) and in-creases program efficiency. Compared to the conventional SiO2 interlayer (IL), this approach significantly improves performance and reliability, resulting in an increase in the memory window (MW) from 1.1 V to 2.4 V and an increase in electron mobility from 105 cm2/V∙s to 382 cm2/V∙s, compared to the control sample. Endurance of 3 × 107 cycles and improved retention characteristics were also achieved.