Bilayer-Based Antiferroelectric HfZrO<sub>2</sub> Tunneling Junction With High Tunneling Electroresistance and Multilevel Nonvolatile Memory

Hsiang, K.-Y.; Liao, C.-Y.; Liu, J.-H.; Wang, J.-F.; Chiang, S.-H.; Chang, Shao Hsi; Hsieh, Fan-Chun; Liang, H.; Lin, Chun Yu; Lou, Z.-F.; Hou, Tuo‐Hung; Liu, C. W.; Lee, M. H.

doi:10.1109/led.2021.3107940

Cited by 25 publications

(9 citation statements)

References 18 publications

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“…These are a nominally DE-free ('HZO only') film, a film with 1.5 nm Al 2 O 3 and a film with 2 nm Al 2 O 3 . Finally, pulse measurements were performed at temperatures from 100-300 K. Assuming that the tunneling mechanism and thus the charge injection in the Al 2 O 3 layers is temperature-dependent (Hsiang et al, 2021), modifying the sample temperature gives control over the trap occupation, thereby also modifying E trap .…”

Section: Measurement Parameter Spacementioning

confidence: 99%

Investigating charge trapping in ferroelectric thin films through transient measurements

Lancaster

Lomenzo

Engl

et al. 2022

Front. Nanotechnol.

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Section: Measurement Parameter Spacementioning

confidence: 99%

Investigating charge trapping in ferroelectric thin films through transient measurements

Lancaster

Lomenzo

Engl

et al. 2022

Front. Nanotechnol.

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“…These are a nominally DE-free ('HZO only') film, a film with 1.5 nm Al 2 O 3 and a film with 2 nm Al 2 O 3 . Finally, pulse measurements were performed at temperatures from 100-300 K. Assuming that the tunneling mechanism and thus the charge injection in the Al 2 O 3 layers is temperature-dependent [15], modifying the sample temperature gives control over the trap occupation, thereby also modifying E trap .…”

Section: Measurement Parameter Spacementioning

confidence: 99%

Investigating charge trapping in ferroelectric thin films through transient measurements

Lancaster,

Lomenzo,

Engl

et al. 2022

Preprint

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A measurement technique is presented to quantify the polarization loss in ferroelectric thin films as a function of delay time during the first 100s after switching. This technique can be used to investigate charge trapping in ferroelectric thin films by analyzing the magnitude and rate of polarization loss.Exemplary measurements have been performed on Hf0.5Zr0.5O2 (HZO) and HZO/Al2O3 films, as a function of pulse width and temperature. It is found that the competing effects of the depolarization field, internal bias field and charge trapping lead to a characteristic Gaussian dependence of the rate of polarization loss on the delay time. From this, a charge trapping and screening model could be identified which describes the dynamics of polarization loss on short timescales. IntroductionCharge trapping at the interfaces of ferroelectric (FE) HfO 2 -based thin films plays an important role in both the dynamics of polarization switching and FE device operation. Charge trapping has a significant impact on device operation in the case of FE field-effect transistors (FeFETs) [22,1] as well as ferroelectric tunnel junctions (FTJs) [9]. In both of these devices, an intentional dielectric (DE) layer is added to a metal-ferroelectric-metal (MFM) stack, which will modulate the impact of charge trapping due to the additional FE-DE interface. Assuming fixed and trapped charge densities is necessary in order to fully model the switching behavior of ferroelectric devices with DE layers [8,14]. Nonetheless, charge trapping is also involved in the switching of HfO 2 ferroelectrics without any intentional interfacial layer (IL) [25,16], due to the unavoidable presence of non-switching 'dead layers' at the FE-electrode interfaces [36]. It has been shown that even after switching, the injection of charges can continue to modify switching behaviour by shifting the coercive voltage through a so-called 'fluid imprint ' effect [4]. As such, a thorough understanding of charge trapping, including its origin, how it can be characterized and how it can be improved or harnessed, is clearly necessary, in order to optimize the operation of FE films in real devices.When a non-switching DE layer is introduced between a FE layer and an electrode, numerous impacts on the FE switching need to be considered. Non-switching layers generate a depolarization field which destabilizes 1

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“…The fatigue mechanisms of ferroelectric layer are attributed to polarization degradation with domain pinning and/or nucleation inhibition for switch cycling [42]. The oxygen vacancies at the interface between the HZO and the TiN electrode benefit the t-phase stability, i.e., suppress the m-phase formation [33,43]. The excessive oxygen vacancies accumulation would lead to a breakdown via strong interactions between the individual vacancies [44].…”

Section: Memory Reliability Of (A)fecapsmentioning

confidence: 99%

“…Furthermore, anti-ferroelectric (AFE) Hf 1−x Zr x O 2 (HZO) is reported to provide a faster switching speed for polarization and a higher fatigue resistance than FE HZO under bipolar electrical cycling [31][32][33]. In addition, lead zirconate titanate (PZT)-based AFE materials applied with a unipolar voltage were reported to show unipolar polarization-electric field (P-E) hysteresis loops [34].…”

Section: Introductionmentioning

confidence: 99%

Unipolar Parity of Ferroelectric-Antiferroelectric Characterized by Junction Current in Crystalline Phase Hf1−xZrxO2 Diodes

et al. 2021

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Ferroelectric (FE) Hf1−xZrxO2 is a potential candidate for emerging memory in artificial intelligence (AI) and neuromorphic computation due to its non-volatility for data storage with natural bi-stable characteristics. This study experimentally characterizes and demonstrates the FE and antiferroelectric (AFE) material properties, which are modulated from doped Zr incorporated in the HfO2-system, with a diode-junction current for memory operations. Unipolar operations on one of the two hysteretic polarization branch loops of the mixed FE and AFE material give a low program voltage of 3 V with an ON/OFF ratio >100. This also benefits the switching endurance, which reaches >109 cycles. A model based on the polarization switching and tunneling mechanisms is revealed in the (A)FE diode to explain the bipolar and unipolar sweeps. In addition, the proposed FE-AFE diode with Hf1−xZrxO2 has a superior cycling endurance and lower stimulation voltage compared to perovskite FE-diodes due to its scaling capability for resistive FE memory devices.

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Bilayer-Based Antiferroelectric HfZrO₂ Tunneling Junction With High Tunneling Electroresistance and Multilevel Nonvolatile Memory

Cited by 25 publications

References 18 publications

Investigating charge trapping in ferroelectric thin films through transient measurements

Investigating charge trapping in ferroelectric thin films through transient measurements

Investigating charge trapping in ferroelectric thin films through transient measurements

Unipolar Parity of Ferroelectric-Antiferroelectric Characterized by Junction Current in Crystalline Phase Hf1−xZrxO2 Diodes

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Bilayer-Based Antiferroelectric HfZrO2 Tunneling Junction With High Tunneling Electroresistance and Multilevel Nonvolatile Memory

Cited by 25 publications

References 18 publications

Investigating charge trapping in ferroelectric thin films through transient measurements

Investigating charge trapping in ferroelectric thin films through transient measurements

Investigating charge trapping in ferroelectric thin films through transient measurements

Unipolar Parity of Ferroelectric-Antiferroelectric Characterized by Junction Current in Crystalline Phase Hf1−xZrxO2 Diodes

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Bilayer-Based Antiferroelectric HfZrO₂ Tunneling Junction With High Tunneling Electroresistance and Multilevel Nonvolatile Memory