Multibit Ferroelectric FET Based on Nonidentical Double HfZrO2 for High-Density Nonvolatile Memory

• Published in: IEEE electron device letters Vol. 42; no. 4; pp. 617 - 620
• Main Authors: Liao, C.-Y., Hsiang, K.-Y., Hsieh, F.-C., Chiang, S.-H., Chang, S.-H., Liu, J.-H., Lou, C.-F., Lin, C.-Y., Chen, T.-C., Chang, C.-S., Lee, M. H.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Density; Erbium; FeFET; FeFETs; ferroelectric; Ferroelectric materials; Ferroelectricity; Iron; Logic gates; Multilevel; Nonvolatile memory; Probability density function; Tin
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3060589

A double-HZO (HfZrO 2 ) FeFET (ferroelectric FET) with nonidentical ferroelectric thicknesses is experimentally demonstrated with as low as <inline-formula> <tex-math notation="LaTeX">\vert {V}_{P/{E}}\vert = {5} </tex-math></inline-formula> V, 2-bit endurance > 10 5 cycles and retention > 10 4 s. Inserting an insulator to separate the ferroelectric layers and avoid the monoclinic formation of a thick Fe-HZO (ferroelectric-HZO) is a useful method to enhance the MW (memory window) for MLC (multilevel cell) applications. Double-HZO has a lower ER (error rate) and shows a 600X improvement compared to single-HZO. The stacked HZO FeFET has potential as an MLC for high-density NVM (nonvolatile memory) applications.