Switching dynamics and modeling of multi-domain Zr-Doped HfO2 ferroelectric thin films

Noh, Youngji; Jung, Moonyoung; Yoon, Jong‐Gul; Hong, Seunghyeon; Park, Sang‐Hyun; Kang, Bo Soo; Ahn, Seung‐Eon

doi:10.1016/j.cap.2019.01.022

Cited by 21 publications

(13 citation statements)

References 22 publications

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“…[25] Different domains have different nucleation rates owing to defects at the interface www.advmattechnol.de or in the interior of the polycrystalline ferroelectric thin film. [26][27][28] Therefore, the polarization reversal rate is a distribution rather than a single value. [29,30] Owing to the distributed switching characteristics, the resistance can be varied gradually between the LRS and HRS, and this analog implementation of the resistance state is the factor most directly related to weight implementation, which is the core element of artificial synaptic devices.…”

Section: Resultsmentioning

confidence: 99%

Highly Stable Artificial Synapses Based on Ferroelectric Tunnel Junctions for Neuromorphic Computing Applications

Song

Ham

Park

et al. 2022

Adv Materials Technologies

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of large-scale network applications. As a solution to the bottleneck of the von Neumann architecture, neuromorphic computing, which mimics the human brain to perform complex computations through massively parallel computations, has been proposed. The human brain consists of more than 10 11 neurons and more than 10 14 synapses. The neurons and synapses are connected in parallel to perform memory, computation, reasoning, and learning simultaneously, even with a low power of ≈20 W. In particular, the human brain learns by reconstructing the connection strength between synapses, called synaptic plasticity. As a result, developing artificial synaptic devices capable of mimicking synaptic plasticity for the implementation of artificial neural networks (ANNs) is a critical challenge. Recently, it has been reported that memristors, which have multiple resistance states that can be continuously modulated by an external electrical stimulus, can mimic the function of biological synapses. [4] Various devices, such as resistive switching memory, [5][6][7][8] phase change memory, [9][10][11] ferroelectric memory, [12][13][14][15] and others, [16][17][18] have been proposed as candidates for high-efficiency and highperformance memristors. A common feature of these devices is that they mimic synaptic weights by expressing values between 0 and 1 in an analog form, as opposed to the current digitalbased information communication devices that only use 0 and 1. Among them, the HfZrO 2 (HZO)-based ferroelectric tunnel junction (FTJ) device controls the partial polarization reversal of a ferroelectric thin film to mimic the synaptic weight. Consequently, it implements a multi-resistance state between the high-resistance state (HRS) and low-resistance state (LRS). [19,20] In addition, synaptic characteristics can be secured using a two-terminal metal-semiconductor-metal (MFM) device structure, which has the advantage of being able to design for high integration of 4F 2 . In this study, we investigated the synaptic properties of the HZO FTJ device with an MFM structure for neuromorphic computing applications. HZO ferroelectric thin films with a non-perovskite structure are appropriate for ultra-thin three dimensional capacitors, because they exhibit ferroelectric properties even in a thin film close to 1 nm and have large bandgaps. Moreover, Ferroelectric doped-HfO 2 is considered an alternative to ferroelectric perovskites because of its full CMOS (complementary metal-oxide-semiconductor) process compatibility, high scalability and easy stabilization Owing to the limited processing speed and power efficiency of the current computing method based on the von Neumann architecture, research on artificial synaptic devices for implementing neuromorphic computing capable of parallel computation is accelerating. The potential application of artificial synapses composed of ferroelectric tunnel junctions based on metal-hafnium zirconium oxide-metal structure for neuromorphic computing is investigated. Multiple resistance levels are implemented t...

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Section: Resultsmentioning

confidence: 99%

Highly Stable Artificial Synapses Based on Ferroelectric Tunnel Junctions for Neuromorphic Computing Applications

Song

Ham

Park

et al. 2022

Adv Materials Technologies

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“…When the required electric field and time for the polarization to switch are different in each ferroelectric domain, the slope of the electrical current I D with respect to the gate voltage V GS becomes more gradual, for both branches of the hysteresis. This indicates that polarization switching takes place in a sequential manner across all grains (Noh et al, 2019).…”

Section: Multi-domain Characterizationmentioning

confidence: 91%

“…To accurately model the peculiarities of HZO layers, a two-to three-dimensional Ginzburg-Landau-type numerical approach is necessary (Chandra and Littlewood, 2007). Important is that it offers the possibility to explicitly account for the presence of grains displaying different polarization switching properties (Noh et al, 2019). In S-Device, such a model has been incorporated into a classical drift-diffusion solver which is employed to describe the electron and hole transport characteristics of the WO x semiconducting channel and to compute the resulting electrical currents (Selberherr, 1984).…”

Section: Introductionmentioning

confidence: 99%

Physical modeling of HZO-based ferroelectric field-effect transistors with a WOx channel

Wen¹,

Halter²,

Bégon‐Lours³

et al. 2022

Front. Nanotechnol.

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The quasistatic and transient transfer characteristics of Hf0.57Zr0.43O2 (HZO)-based ferroelectric field-effect transistors (FeFETs) with a WOx channel are investigated using a 2-D time-dependent Ginzburg-Landau model as implemented in a state-of-the-art technology computer aided design tool. Starting from an existing FeFET configuration, the influence of different design parameters and geometries is analyzed before providing guidelines for next-generation devices with an increased “high (RH) to low (RL)” resistance ratio, i.e., RH/RL. The suitability of FeFETs as solid-state synapses in memristive crossbar arrays depends on this parameter. Simulations predict that a 13 times larger RH/RL ratio can be achieved in a double-gate FeFET, as compared to a back-gated one with the same channel geometry and ferroelectric layer. The observed improvement can be attributed to the enhanced electrostatic control over the semiconducting channel thanks to the addition of a second gate. A similar effect is obtained by thinning either the HZO dielectric or the WOx channel. These findings could pave the way for FeFETs with enhanced synaptic-like properties that play a key role in future neuromorphic computing applications.

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“…Since the Si: HfO 2 thin film used in this experiment is multi-domain, as shown in the P-V characteristic curve, the polarization switching gradually occurs starting before the coercive voltage (V C ) ( Figure S2, Supporting Information). To express the polarization characteristics of a multi-domain ferroelectric thin film, a normal distribution (Equation 14) is used for the probability density function representing the switching [42]…”

Section: T P Rmentioning

confidence: 99%

Compensation Charge Control and Modeling for Reproducing Negative Capacitance Effect of Hafnia Ferroelectric Thin Films

Ahn

Jung

Lee

et al. 2020

Adv Materials Inter

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To enable continuing development of the performance of highly integrated semiconductor chips, it is necessary to dramatically lower the power consumption of transistors. The discovery of the negative capacitance (NC) effect and the ferroelectric properties of HfO2 thin films have raised the possibility of surpassing the known physical limitations of the 60 mV subthreshold slope of the current MOSFETs. However, for commercial application, stable reproducibility of the voltage drop effect due to the ferroelectric polarization and a model that can fully interpret this phenomenon must be obtained. Despite intense recent efforts, guidance for the design of devices for mass production based on the NC effect is currently unavailable. This study has directly observed the NC effect and confirmed that the NC effect can be controlled through analysis based on the equivalent circuit theory. It is experimentally verified that the NC effect is caused by an imbalance between the amount of polarization switching and the amount of charge supplied to compensate for such switching in the initial stage of the applied voltage pulse. The results suggest that a gate structure or peripheral circuit that can actively respond to polarization switching is necessary to implement a novel MOSFET with breakthrough power consumption.

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Switching dynamics and modeling of multi-domain Zr-Doped HfO2 ferroelectric thin films

Cited by 21 publications

References 22 publications

Highly Stable Artificial Synapses Based on Ferroelectric Tunnel Junctions for Neuromorphic Computing Applications

Highly Stable Artificial Synapses Based on Ferroelectric Tunnel Junctions for Neuromorphic Computing Applications

Physical modeling of HZO-based ferroelectric field-effect transistors with a WOx channel

Compensation Charge Control and Modeling for Reproducing Negative Capacitance Effect of Hafnia Ferroelectric Thin Films

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