Deep electron traps in HfO2-based ferroelectrics: (Al/Si-doped) HfO2 versus HfZrO4

Izmailov, R. A.; O’Sullivan, B. J.; Popovici, Mihaela; Afanasʼev, Valeri

doi:10.1016/j.sse.2022.108388

Cited by 4 publications

(1 citation statement)

References 14 publications

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“…9.5-nm-thick HfO 2 layers were synthesized by ALD from HfCl 4 and H 2 O precursors at a substrate temperature of 300 °C on top of 7.5-nm-thick SiO 2 layers thermally grown on low-doped p-type Si(100) substrates as described in ref . In order to stabilize the ferroelectric phase, several ALD cycles of Al or Si precursor were included, resulting in the doped (5.5%) Al:HfO 2 and (3.6%) Si:HfO 2 films.…”

Section: Methodsmentioning

confidence: 99%

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of Hf_xSi_1–xO₂ at the SiO₂/FE:HfO₂ Interface in a Ferroelectric Field-Effect Transistor

et al. 2023

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Characterization of the composition and extension of the SiO2/HfO2 interface in the model systems Si-sub./SiO2 (7.5 nm)/FE:HfO2 (9.5 nm)/TiN (9 nm) for standard impurity concentrations and annealing temperatures (Si 3.6%, 1000 °C; Al 5.5%, 850 °C) were carried out using X-ray photoelectron spectroscopy with high kinetic energies. In addition, the crystalline properties of HfO2 were characterized by transmission electron microscopy and grazing incidence X-ray diffraction depending on the type of impurity. Formation of Hf x Si1–x O2 at the SiO2/HfO2 interface was revealed, and the dependence of its thickness d silicate and stoichiometry X on the formation of the tetragonal phase P42/nmc of HfO2 was established. It is shown that doping with aluminum followed by annealing prevents the formation of a tetragonal phase and reduces both d silicate and X by about 20% (with respect to undoped HfO2 annealed at the same temperature), in contrast to doping with Si followed by annealing, which practically does not affect d silicate and X. The results obtained are important for the problem of imbalance in the voltage drop across the gate oxides stack in a ferroelectric field-effect transistor and improvement of its endurance and retention characteristics.

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Section: Methodsmentioning

confidence: 99%

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of Hf_xSi_1–xO₂ at the SiO₂/FE:HfO₂ Interface in a Ferroelectric Field-Effect Transistor

et al. 2023

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The Reliability Impact of Bi Doping on the HfO2 Charge-Trapping Layer: A First-Principles Study

Ye,

Zhu,

Yuan

et al. 2024

J. Electron. Mater.

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Electron emission from deep traps in HfO2 under thermal and optical excitation

Izmailov,

Strand,

Ronchi

et al. 2024

Phys. Rev. B

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The ratio between the energies of optical and thermal ionization depends on the defect nature and the strength of the interaction of trapped electrons with phonons. Knowing this ratio for a certain type of defect allows one to predict, e.g., thermal emission energies from the optically measured values. We present the results of direct empirical extraction of the ratio between optical and thermal electron emission energies for HfO2 bulk electron traps combined with theoretical analysis of the physical mechanism of electron transitions from the trapped state to the mobility edge. We show that, by applying different excitation mechanisms, we affect the same deep traps inside the HfO2 band gap; i.e., these traps are both optically and thermally active and are likely to have similar nature. The extracted empirical optical/thermal ionization energy ratio of 2.2±0.3 is in good agreement with the polaronic nature of the probed electron traps, as shown by the results of theoretical calculations. Our results provide experimental and theoretical methodologies for consistently linking thermal and optical ionization energies of electron traps and describing their distributions in the band gap of amorphous oxides, and can help improve modeling frameworks for reliability issues related to oxide traps. Published by the American Physical Society 2024

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Deep electron traps in HfO2-based ferroelectrics: (Al/Si-doped) HfO2 versus HfZrO4

Cited by 4 publications

References 14 publications

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of Hf_xSi_1–xO₂ at the SiO₂/FE:HfO₂ Interface in a Ferroelectric Field-Effect Transistor

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of Hf_xSi_1–xO₂ at the SiO₂/FE:HfO₂ Interface in a Ferroelectric Field-Effect Transistor

The Reliability Impact of Bi Doping on the HfO2 Charge-Trapping Layer: A First-Principles Study

Electron emission from deep traps in HfO2 under thermal and optical excitation

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Deep electron traps in HfO2-based ferroelectrics: (Al/Si-doped) HfO2 versus HfZrO4

Cited by 4 publications

References 14 publications

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of HfxSi1–xO2 at the SiO2/FE:HfO2 Interface in a Ferroelectric Field-Effect Transistor

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of HfxSi1–xO2 at the SiO2/FE:HfO2 Interface in a Ferroelectric Field-Effect Transistor

The Reliability Impact of Bi Doping on the HfO2 Charge-Trapping Layer: A First-Principles Study

Electron emission from deep traps in HfO2 under thermal and optical excitation

Contact Info

Product

Resources

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Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of Hf_xSi_1–xO₂ at the SiO₂/FE:HfO₂ Interface in a Ferroelectric Field-Effect Transistor

Role of Postdeposition Annealing and Doping with Si and Al Impurities in the Formation of Hf_xSi_1–xO₂ at the SiO₂/FE:HfO₂ Interface in a Ferroelectric Field-Effect Transistor