Carrier confinement effect-driven channel design and achievement of robust electrical/photostability and high mobility in oxide thin-film transistors

Ahn, Cheol Hyoun; Cho, Hyung Koun; Kim, Hyoungsub

doi:10.1039/c5tc03766b

Cited by 14 publications

(11 citation statements)

References 44 publications

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“…It facilitates conformal material deposition with a high degree of reproducibility of thin layered films with a superior control over film thickness due to its intrinsic reaction-controlled film deposition. This advantage allows the possibility of precise deposition over large-area substrates, either planar or three-dimensional structured with precise thickness control at angstrom levels, which is enabled by surface-limited reactions of the molecular precursors employed. − In this context, heterostructure devices based on aluminum oxide/zinc oxide and aluminum oxide/indium oxide compositions have been demonstrated, showing considerable evidence of tunability of their properties in favor of high-performance semiconductor/conductor behavior. , Thus, the ALD technique offers its largely underutilized potential to take advantage of such phenomena arising at the heterointerface and enabling their fine-tuning on a more or less atomic scale. ,, In this realm, we have recently reported on multilayered heterostructures obtained by ALD, consisting of alternating layers of In 2 O 3 and ZnO …”

Section: Introductionmentioning

confidence: 99%

Charge Transport in Low-Temperature Processed Thin-Film Transistors Based on Indium Oxide/Zinc Oxide Heterostructures

Krausmann

Sanctis

Engstler

et al. 2018

ACS Appl. Mater. Interfaces

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The influence of the composition within multilayered heterostructure oxide semiconductors has a critical impact on the performance of thin-film transistor (TFT) devices. The heterostructures, comprising alternating polycrystalline indium oxide and zinc oxide layers, are fabricated by a facile atomic layer deposition (ALD) process, enabling the tuning of its electrical properties by precisely controlling the thickness of the individual layers. This subsequently results in enhanced TFT performance for the optimized stacked architecture after mild thermal annealing at temperatures as low as 200 °C. Superior transistor characteristics, resulting in an average field-effect mobility (μ) of 9.3 cm V s ( W/ L = 500), an on/off ratio ( I/ I) of 5.3 × 10, and a subthreshold swing of 162 mV dec, combined with excellent long-term and bias stress stability are thus demonstrated. Moreover, the inherent semiconducting mechanism in such multilayered heterostructures can be conveniently tuned by controlling the thickness of the individual layers. Herein, devices comprising a higher InO/ZnO ratio, based on individual layer thicknesses, are predominantly governed by percolation conduction with temperature-independent charge carrier mobility. Careful adjustment of the individual oxide layer thicknesses in devices composed of stacked layers plays a vital role in the reduction of trap states, both interfacial and bulk, which consequently deteriorates the overall device performance. The findings enable an improved understanding of the correlation between TFT performance and the respective thin-film composition in ALD-based heterostructure oxides.

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Section: Introductionmentioning

confidence: 99%

Charge Transport in Low-Temperature Processed Thin-Film Transistors Based on Indium Oxide/Zinc Oxide Heterostructures

Krausmann

Sanctis

Engstler

et al. 2018

ACS Appl. Mater. Interfaces

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“…However, in order to realize high definition, high frame-rate displays, and the relevant driving circuitry, the carrier mobility must be further improved while exhibiting good operational stability. For these reasons, various metal-oxide semiconductors [ 7 , 8 ], gate dielectrics [ 9 , 10 ], novel device structures [ 11 , 12 ], and post treatments [ 13 , 14 ] have been proposed to enhance the carrier mobility of these devices. Among the various approaches in achieving high mobility metal-oxide TFTs, using an ionic-type gate dielectric is a promising method of achieving both the high mobility and low voltage operation characteristics [ 15 , 16 , 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Frequency-Stable Ionic-Type Hybrid Gate Dielectrics for High Mobility Solution-Processed Metal-Oxide Thin-Film Transistors

Heo

Choi

et al. 2017

Materials

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In this paper, we demonstrate high mobility solution-processed metal-oxide thin-film transistors (TFTs) by using a high-frequency-stable ionic-type hybrid gate dielectric (HGD). The HGD gate dielectric, a blend of sol-gel aluminum oxide (AlOx) and poly(4-vinylphenol) (PVP), exhibited high dielectric constant (ε~8.15) and high-frequency-stable characteristics (1 MHz). Using the ionic-type HGD as a gate dielectric layer, an minimal electron-double-layer (EDL) can be formed at the gate dielectric/InOx interface, enhancing the field-effect mobility of the TFTs. Particularly, using the ionic-type HGD gate dielectrics annealed at 350 °C, InOx TFTs having an average field-effect mobility of 16.1 cm2/Vs were achieved (maximum mobility of 24 cm2/Vs). Furthermore, the ionic-type HGD gate dielectrics can be processed at a low temperature of 150 °C, which may enable their applications in low-thermal-budget plastic and elastomeric substrates. In addition, we systematically studied the operational stability of the InOx TFTs using the HGD gate dielectric, and it was observed that the HGD gate dielectric effectively suppressed the negative threshold voltage shift during the negative-illumination-bias stress possibly owing to the recombination of hole carriers injected in the gate dielectric with the negatively charged ionic species in the HGD gate dielectric.

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“…Moreover, the hysteretic phenomenon reduces in the transfer curves of Nd:IZO/Al 2 O 3 TFT. According to our previous study [ 11 ] and other reports [ 12 , 13 ], the Al 2 O 3 acts as an electrical controller layer, inducing high-flux electron movement in the bulk and near-channel regions of the semiconductor layer by the carrier confinement effect under an electrical field, which avoids the scatting and trapping effect by the back-channel defects, and hence efficiently improves the device’s mobility. Meanwhile, in the Nd:IZO/Al 2 O 3 system, the Al 2 O 3 layer should have a specific role in the modification of the Nd:IZO semiconductor layer, which will be further discussed in this paper.…”

Section: Resultsmentioning

confidence: 99%

High-Performance Thin Film Transistor with an Neodymium-Doped Indium Zinc Oxide/Al2O3 Nanolaminate Structure Processed at Room Temperature

Yao

Zheng

et al. 2018

Materials

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In this work, a high-performance thin film transistor with an neodymium-doped indium zinc oxide (Nd:IZO) semiconductor via a room temperature approach and adopting the Nd:IZO/Al2O3 nanolaminate structure was investigated. The effects of the ultrathin Al2O3 layer and the thickness of Nd:IZO layer in the nanolaminate structure on the improvement of electrical performance and stability of thin film transistors (TFTs) were systematically studied. Besides the carrier movement confined along the near-channel region, driven by the Al2O3 layer under an electrical field, the high performance of the TFT is also attributed to the high quality of the 8-nm-thick Nd:IZO layer and the corresponding optimal Nd:IZO/Al2O3 interface, which reduce the scattering effect and charge trapping with strong M–O bonds in bulk and the back-channel surface of Nd:IZO, according to the X-ray reflectivity (XRR), X-ray photoelectron spectroscopy (XPS), and micro-wave photo conductivity decay (μ-PCD) results. As a result, the Nd:IZO/Al2O3 TFT exhibits an outstanding performance, with a high μsat of 32.7 cm2·V−1·s−1, an Ion/Ioff of 1.9 × 108, and a low subthreshold swing (SS) value of 0.33 V·dec−1, which shows great potential for the room temperature fabrication of TFTs in high-resolution or high-frame-rate displays by a scalable, simple, and feasible approach.

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Carrier confinement effect-driven channel design and achievement of robust electrical/photostability and high mobility in oxide thin-film transistors

Abstract: Carrier confinement effect-driven channel structures promoted stability under photo-bias stress condition, which was attributed increased recombinations events between photo-ionized oxygen vacancies and charged electrons due to the effective carrier confinement.

Cited by 14 publications

References 44 publications

Charge Transport in Low-Temperature Processed Thin-Film Transistors Based on Indium Oxide/Zinc Oxide Heterostructures

Charge Transport in Low-Temperature Processed Thin-Film Transistors Based on Indium Oxide/Zinc Oxide Heterostructures

Frequency-Stable Ionic-Type Hybrid Gate Dielectrics for High Mobility Solution-Processed Metal-Oxide Thin-Film Transistors

High-Performance Thin Film Transistor with an Neodymium-Doped Indium Zinc Oxide/Al2O3 Nanolaminate Structure Processed at Room Temperature

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