An Aqueous Route to Oxygen-Deficient Wake-Up-Free La-Doped HfO2 Ferroelectrics for Negative Capacitance Field Effect Transistors

Pujar, P and Cho, H and Kim, Y-H and Zagni, N and Oh, J and Lee, E and Gandla, S and Nukala, P and Kim, Y-M and Alam, MA and Kim, S (2023) An Aqueous Route to Oxygen-Deficient Wake-Up-Free La-Doped HfO2 Ferroelectrics for Negative Capacitance Field Effect Transistors. In: ACS nano, 17 (19). pp. 19076-19086.

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Abstract

The crucial role of nanocrystalline morphology in stabilizing the ferroelectric orthorhombic (o)-phase in doped-hafnia films is achieved via chemical solution deposition (CSD) by intentionally retaining carbonaceous impurities to inhibit grain growth. However, in the present study, large-grained (>100 nm) La-doped HfO2 (HLO) films are grown directly on silicon by adopting engineered water-diluted precursors with a minimum carbonaceous load and excellent shelf life. The o-phase stabilization is accomplished through a well-distributed La dopant, which generates uniformly populated oxygen vacancies, eliminating the need for oxygen-scavenging electrodes. These oxygen-deficient HLOs show a maximum remnant polarization of 37.6 μC/cm2 (2Pr) without wake-up and withstand large fields (>6.2 MV/cm). Furthermore, CSD-HLO in series with Al2O3 improves switching of MOSFETs (with an amorphous oxide channel) based on the negative capacitance effect. Thus, uniformly distributed oxygen vacancies serve as a standalone factor in stabilizing the o-phase, enabling efficient wake-up-free ferroelectricity without the need for nanostructuring, capping stresses, or oxygen-reactive electrodes.

Item Type:	Journal Article
Publication:	ACS nano
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to the American Chemical Society.
Department/Centre:	Division of Interdisciplinary Sciences > Centre for Nano Science and Engineering
Date Deposited:	30 Nov 2023 07:17
Last Modified:	30 Nov 2023 07:17
URI:	https://eprints.iisc.ac.in/id/eprint/83392

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