{"title":"Origin of charges in bulk Si:HfO2 FeFET probed by nanosecond polarization measurements","authors":"","doi":"10.1016/j.mee.2024.112284","DOIUrl":null,"url":null,"abstract":"<div><div>FeFET technology offers the potential for fast, energy-efficient, low-cost, and high-capacity non-volatile memory and neuromorphic devices. However, charge trapping significantly affects device operation, leading to issues like read-after-write delay and limited endurance. Therefore, a detailed understanding of charge trapping, charge origin and its role in polarization switching is crucial. In this study, we uncover the spectral energy origin of polarization charges in Si:HfO<sub>2</sub> N-FeFET by probing electron (conduction band) and hole (valence band) currents separately during polarization-voltage (<em>P–V</em>) measurements. We utilize a fast (∼20 ns) and modified positive-up-negative-down (PUND) technique, where bulk, source, and drain currents of the FeFET are measured separately. The nanosecond timescale of the measurement results in measurable currents in FeFETs having dimensions of a few μm. This charge separation shows that program (PRG, <em>V</em><sub>GS</sub> > 0) charge originates from the conduction band, whereas erase (ERS, <em>V</em><sub>GS</sub> < 0) originates from the valence band of the Si. Moreover, the polarization curve (<em>P–V</em>) of a cycled device (following 5000 PRG/ERS pulses) shows measurable hysteresis even though the transfer curve of the same device shows that the memory window in the threshold voltage vanishes. Therefore, the FeFET polarization state can be read without delay after write operation by the fast PUND measurement, both for pristine and cycled FeFETs.</div></div>","PeriodicalId":18557,"journal":{"name":"Microelectronic Engineering","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Microelectronic Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0167931724001539","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}
引用次数: 0
Abstract
FeFET technology offers the potential for fast, energy-efficient, low-cost, and high-capacity non-volatile memory and neuromorphic devices. However, charge trapping significantly affects device operation, leading to issues like read-after-write delay and limited endurance. Therefore, a detailed understanding of charge trapping, charge origin and its role in polarization switching is crucial. In this study, we uncover the spectral energy origin of polarization charges in Si:HfO2 N-FeFET by probing electron (conduction band) and hole (valence band) currents separately during polarization-voltage (P–V) measurements. We utilize a fast (∼20 ns) and modified positive-up-negative-down (PUND) technique, where bulk, source, and drain currents of the FeFET are measured separately. The nanosecond timescale of the measurement results in measurable currents in FeFETs having dimensions of a few μm. This charge separation shows that program (PRG, VGS > 0) charge originates from the conduction band, whereas erase (ERS, VGS < 0) originates from the valence band of the Si. Moreover, the polarization curve (P–V) of a cycled device (following 5000 PRG/ERS pulses) shows measurable hysteresis even though the transfer curve of the same device shows that the memory window in the threshold voltage vanishes. Therefore, the FeFET polarization state can be read without delay after write operation by the fast PUND measurement, both for pristine and cycled FeFETs.
期刊介绍:
Microelectronic Engineering is the premier nanoprocessing, and nanotechnology journal focusing on fabrication of electronic, photonic, bioelectronic, electromechanic and fluidic devices and systems, and their applications in the broad areas of electronics, photonics, energy, life sciences, and environment. It covers also the expanding interdisciplinary field of "more than Moore" and "beyond Moore" integrated nanoelectronics / photonics and micro-/nano-/bio-systems. Through its unique mixture of peer-reviewed articles, reviews, accelerated publications, short and Technical notes, and the latest research news on key developments, Microelectronic Engineering provides comprehensive coverage of this exciting, interdisciplinary and dynamic new field for researchers in academia and professionals in industry.