Multilevel Operation in Scaled Back-End-of-Line Ferroelectric FETs With a Metal Interlayer

Multi-level operation, conventionally obtained in ferroelectric devices thanks to a domain-dependent inhomogeneous polarization, poses a big challenge for highly-scaled ferroelectric devices, where the number of ferroelectric domains is drastically reduced. In this work, we study a highly scaled bac...

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Bibliographic Details
Main Authors: Chiara Rossi, Daniel Lizzit, David Esseni
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/10966879/
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Summary:Multi-level operation, conventionally obtained in ferroelectric devices thanks to a domain-dependent inhomogeneous polarization, poses a big challenge for highly-scaled ferroelectric devices, where the number of ferroelectric domains is drastically reduced. In this work, we study a highly scaled back-end-of-line (BEOL) compatible, ferroelectric field-effect transistor (FeFET) that integrates a metal interlayer in the gate stack. Through analytical models and calibrated TCAD simulations, we show how this device can achieve a multi-level operation exploiting the interplay between the ferroelectric polarization and the charge in the metal interlayer. Such a working principle does not rely on a domain-dependent inhomogeneous polarization, and the device operation is thus ensured also for a homogeneous ferroelectric material. We also demonstrate that the charge in the interlayer can effectively stabilize the ferroelectric polarization even in the absence of a high concentration of trapped charges in the gate stack. The potentiation and depression curves for the readout conductance confirm that the proposed device can be operated as a memristor for neuromorphic computing applications. Moreover, we show how the choice of the dielectric in the metal-ferroelectric-dielectric-metal gate stack can be used as a design knob to reduce the device operation voltage.
ISSN:2169-3536