Analysis of memory retention characteristics of ferroelectric field effect transistors using a simple metal–ferroelectric–metal–insulator–semiconductor structure

Ashikaga, Kinya; Ito, Toshio

doi:10.1063/1.369381

Cited by 21 publications

(6 citation statements)

References 8 publications

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“…This phenomenon might have originated from the polarization relaxation of the ferroelectric domain (37)(38). The polarization loss can be accelerated by polarization shielding effects of injected and trapped mobile charges and by the depolarization field inevitably remaining in the ferroelectric film during retention interval (39)(40). However, we should note that the I PSC relaxation could substantially affect the learning accuracy if enough time has passed, which is one of the challenges of the ferroelectric-based synapse (fig.…”

Section: Synaptic Characteristics and Switching Mechanismmentioning

confidence: 99%

One-dimensional organic artificial multi-synapses enabling electronic textile neural network for wearable neuromorphic applications

et al. 2020

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One-dimensional (1D) devices are becoming the most desirable format for wearable electronic technology because they can be easily woven into electronic (e-) textile(s) with versatile functional units while maintaining their inherent features under mechanical stress. In this study, we designed 1D fiber-shaped multi-synapses comprising ferroelectric organic transistors fabricated on a 100-μm Ag wire and used them as multisynaptic channels in an e-textile neural network for wearable neuromorphic applications. The device mimics diverse synaptic functions with excellent reliability even under 6000 repeated input stimuli and mechanical bending stress. Various NOR-type textile arrays are formed simply by cross-pointing 1D synapses with Ag wires, where each output from individual synapse can be integrated and propagated without undesired leakage. Notably, the 1D multi-synapses achieved up to ~90 and ~70% recognition accuracy for MNIST and electrocardiogram patterns, respectively, even in a single-layer neural network, and almost maintained regardless of the bending conditions.

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Section: Synaptic Characteristics and Switching Mechanismmentioning

confidence: 99%

One-dimensional organic artificial multi-synapses enabling electronic textile neural network for wearable neuromorphic applications

et al. 2020

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“…18 However, their retention properties, which are closely related to the performance of memory devices, have been studied less. [19][20][21][22][23][24] In this article, we focus on investigation of polarization decay dynamics by means of SFM and on the effect of the switching pulse parameters, switching prehistory, and domain polarity on polarization retention. It will be shown how a particular bottom electrode material affects film retentivity.…”

Section: Introductionmentioning

confidence: 99%

Polarization retention in SrBi2Ta2O9 thin films investigated at nanoscale

Gruverman¹,

Tanaka²

2001

Journal of Applied Physics

111

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The nanoscale mechanism of retention behavior in SrBi 2 Ta 2 O 9 ͑SBT͒ thin films has been investigated by means of piezoresponse scanning force microscopy. It has been found that SBT films with Pt electrodes ͑SBT/Pt͒ exhibit a strong dependence of retention characteristics upon domain polarity: positive domains with the polarization vector pointing to the bottom electrode exhibit excellent stability in sharp contrast to the negative domains which show poor retention. The backswitching of the negative domains proceeds via sidewise motion of the domain walls and shows a log-time dependence. The strong effect of the poling voltage parameters ͑duration and amplitude͒ and the previous switching pattern on domain retention behavior is reported. On the other hand, in SBT films with IrO 2 electrodes ͑SBT/IrO 2 ), the written domains of both polarities show no sign of relaxation to the original state irrespective of the parameters of the poling voltage. The difference in retention behavior of opposite domains in SBT/Pt films is explained by the presence of the polarization-independent built-in bias at the SBT/Pt interface pointing to the bottom electrode. This built-in bias triggers the backswitching of a negative domain by generating positive nuclei at the interface. The forward growth of the nuclei is further governed by the field of the space charge which screens the original polarization state. The symmetric retention behavior and the stability of domain in SBT films with IrO 2 electrodes are attributed to the inhibition of the nucleation process at the SBT/IrO 2 interface.

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“…Among several polytypes, 4H-SiC is considered as the most attractive one because of its wider bandgap (E g ∼ = 3.2 eV) as well as higher and more isotropic bulk mobility than other polytypes. However, up to now the electrical properties and the defect charges in SiC MF(I)S have not been studied in detail [9,10] and the studies on MFMIS have only been on Si. In this work, we report on the electrical characteristics and the properties of MFMIS and MF(I)S structures on 4H-SiC as well as process integration for FETs using these structures.…”

Section: Introductionmentioning

confidence: 98%

Processing and Properties of Ferroelectric Pb(Zr,Ti)O 3 /Silicon Carbide Field-Effect Transistor

Koo¹,

Khartsev²,

Zetterling³

et al. 2003

Integrated Ferroelectrics

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Metal-ferroelectric-(insulator)-semiconductor MF(I)S structures have been fabricated and the properties of pulsed laser-deposited PZT/Al 2 O 3 gate stacks have been studied on n-and p-type 4H-SiC. Among several polytypes of SiC, 4H-SiC is considered as the most attractive one because of its wider bandgap (E g ∼ = 3.2 eV) as well as higher and more isotropic bulk mobility than other polytypes. Single PZT phase without a preferred orientation was confirmed by x-ray diffraction. The interface trap densities N IT , fixed oxide charges Q F , and trapped oxide charges Q HY have been estimated by C-V curves with and without photo-illuminated measurements at room temperature. It is found that the charge injection from SiC is the dominant mechanism for C-V hysteresis. Importantly, with PZT/Al 2 O 3 gate stacks, superior C-V characteristics with negligible sweep rate dependence and negligible time dependence under the applied bias were obtained compared to PZT directly deposited on SiC. The MFIS structures exhibited very stable capacitance-voltage C-V loops with low conductance (<0.1 mS/cm 2 , tan δ ∼ 0.0007 at 400 kHz) and memory window as wide as 10 V, when 5 nm-thick Al 2 O 3 was used as a high bandgap (E g ∼ 9 eV) barrier buffer layer between PZT (E g ∼ 3.5 eV) and SiC (E g ∼ 3.2 eV). The structures have shown excellent electrical properties promising for the gate stacks as the SiC field-effect transistors (FETs). Depletion mode transistors were prepared by forming a Pb(Zr 0.52 Ti 0.48 )O 3 /Al 2 O 3 gate stack on 4H-SiC. Based on this structure, ferroelectric Pb(Zr,Ti)O 3 (PZT) thin films have been integrated on 4H-silicon carbide (SiC) in a SiC field-effect transistor process. Nonvolatile operation of ferroelectric-gate field-effect transistors in silicon carbide (SiC) is demonstrated. 1221 1222 SANG-MO KOO et al.

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Analysis of memory retention characteristics of ferroelectric field effect transistors using a simple metal–ferroelectric–metal–insulator–semiconductor structure

Cited by 21 publications

References 8 publications

One-dimensional organic artificial multi-synapses enabling electronic textile neural network for wearable neuromorphic applications

One-dimensional organic artificial multi-synapses enabling electronic textile neural network for wearable neuromorphic applications

Polarization retention in SrBi2Ta2O9 thin films investigated at nanoscale

Processing and Properties of Ferroelectric Pb(Zr,Ti)O 3 /Silicon Carbide Field-Effect Transistor

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