Improvements in the device characteristics of amorphous indium gallium zinc oxide thin-film transistors by Ar plasma treatment

Park, Jin‐Seong; Jeong, Jae Kyeong; Mo, Yeon‐Gon; Kim, Hye Dong; Kim, Sunil

doi:10.1063/1.2753107

Cited by 338 publications

(199 citation statements)

References 16 publications

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“…In fact it is reported that the Ar plasma treated surface has relatively higher In and relatively lower Ga and Zn due to the difference of the sputtering yield of these atoms. 20 However, these differences are reduced after an annealing step. In case of TFT with mf-PVD ESLs, high mobility and negative V TH could be due to the change in the conductivity of the channel at the ESL interface.…”

Section: Resultsmentioning

confidence: 99%

Medium Frequency Physical Vapor Deposited Al₂O₃and SiO₂as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Nag

Bhoolokam

Chasin

et al. 2015

ECS J. Solid State Sci. Technol.

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In this work, we report on amorphous-Indium-Gallium-Zinc-Oxide (a-IGZO) thin-film transistor (TFT) with medium frequency physical vapor deposited (mf-PVD) etch-stop-layer (ESL). TFT with mf-PVD ESL show comparable characteristics such as fieldeffect mobility (μ FE ), sub-threshold slope (SS −1 ) and current ratio (I ON/OFF ) to the conventional plasma enhanced chemical vapor deposition (PECVD) ESL based TFT, however significant differences were observed in gate bias-stress stabilities. The TFTs with mf-PVD ESL showed lower threshold-voltage (V TH ) shifts compared to TFTs with PECVD ESL when stressed under a gate field of +/−1 MV/cm for duration of 10 4 seconds in dark and light conditions. We associate the better bias-stress stability of the mf-PVD ESL based TFT to better passivating properties and the low hydrogen content of the mf-PVD layer compared to PECVD layer. Amorphous oxide semiconductors (AOSs) are gaining traction to replace the a:SiH in TFTs applied in liquid crystal display (LCD) and organic light-emitting diode display (OLED) backplanes. These oxide semiconductor have high transparency and relatively high electron mobility in the amorphous state. An additional advantage lies in the low process temperature required for AOS integration on plastic film and so potentially enabling flexible transparent display and electronics. Among many AOSs, a-IGZO is the most promising due to its high mobility, excellent uniformity, and the compatibility with transparent and flexible substrate, as compared to conventional amorphous and polycrystalline silicon.1-8 For either LCD or OLED displays with IGZO backplane, bottom-gate top-contact (BGTC) ESL configuration is preferred. The ESL protects the a-IGZO back channel from damages caused during the source-drain metallization and patterning.9-11 The damage-free surface improves the bias stabilities especially at accelerated bias stress conditions under illumination. However commonly the ESL is deposited by plasma assisted CVD processes to which a-IGZO can be sensitive.12 Therefore there is a need to investigate the effect of the ESL on the characteristics of a-IGZO TFTs.PECVD based SiO 2 deposited at temperature higher than 350• C using SiH 4 /N 2 O chemistry is commonly used as an ESL in Flat-PanelDisplay (FPD) industry due to its fast deposition rate, high uniformity and good step coverage. For the integration on commercialized flexible substrates like PEN or polyimide, deposition and process temperature should be lower to prevent shrinkage of the plastic foil and allow easy de-lamination. It is known that PECVD layer deposited at lower temperature deteriorate layer quality leading to lower density, higher amount of dangling bonds and an increase in the amount of hydrogen incorporated into the SiO 2 layer. The poor density and increase of hydrogen is problematic for a-IGZO TFTs because it leads to uncontrolled doping density. [13][14] Few research groups have demonstrated the use of PVD based dielectrics (SiO 2 and Al 2 O 3 ) as passivation layer or ESL as an altern...

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Section: Resultsmentioning

confidence: 99%

Medium Frequency Physical Vapor Deposited Al₂O₃and SiO₂as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Nag

Bhoolokam

Chasin

et al. 2015

ECS J. Solid State Sci. Technol.

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“…However, l sat for In-Si-O can be improved by optimizing the O 2 partial pressure used during sputtering. Further improvement can be expected by modifying the contact electrode 17 and by using Ar plasma treatment 18 or excimer laser irradiation.…”

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confidence: 99%

Effects of dopants in InOx-based amorphous oxide semiconductors for thin-film transistor applications

Aikawa¹,

Nabatame²,

Tsukagoshi³

2013

Applied Physics Letters

113

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Amorphous metal oxide thin-film transistors (TFT) are fabricated using InO x -based semiconductors doped with TiO 2 , WO 3 or SiO 2 . Although density of dopant is low in the film, change in the electrical properties showed strong dependence on the dopant species. We found that the dependence could be reasonably explained by the bond-dissociation energy. By incorporating the dopant with higher bond-dissociation energy, the film becomes less sensitive to oxygen partial pressure used during sputtering deposition and remains electrically stable to thermal annealing treatment. The concept of bond-dissociation energy can contribute to the realization of more stable metal oxide TFTs for flat panel displays.

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“…23,26,32,[49][50][51][52] According to the Hall effect measurement, carrier concentration of the pristine IGZO thin film is order of ∼10 19 cm −3 , but can be increased up to 10 20 ∼ 10 21 cm −3 by additional Argon treatment. 38,53 The doping concentration of the graphene under dark condition can be calculated by gating experiment and capacitance-voltage measurement. The dopant density arising from the gate voltage can be expressed as n = 1/π(E/ -hv F ) 2 , where E is the Fermi energy under gate bias and v F ∼ 10 8 cm/s is the Fermi velocity of the graphene.…”

Section: Resultsmentioning

confidence: 99%

Dual Mode Photocurrent Generation of Graphene-Oxide Semiconductor Junction

Jeong

Heo

Kyoung

et al. 2015

ECS J. Solid State Sci. Technol.

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The need for low-cost and highly versatile photosensing devices keeps increasing. In this work, we present a heterojunction device based on wafer-scale graphene grown by chemical vapor deposition (CVD) and sputtered InGaZnO (IGZO) semiconductor for dual mode photocurrent collection. The photocurrent can be collected either from the lateral gold/graphene/gold configuration or from the vertical graphene/IGZO/nickel heterojunction configuration with no external bias. Incident-energy-dependent photocurrent scanning microscopy shows that the dominant photocarriers are formed at the edge of the gold electrode through photo-thermoelectric hot hole generation in the lateral configuration. Vertical mode renders unidirectional current flow by photoexcited electrons in the IGZO and the subsequent relaxation and diffusion due to Fowler-Nordheim potential. © 2015 The Electrochemical Society. [DOI: 10.1149/2.0071512jss] All rights reserved.Manuscript submitted July 7, 2015; revised manuscript received September 9, 2015. Published September 22, 2015 Graphene is a two dimensional carbon-chained material that has been extensively studied for promising photonic and optoelectronic applications.1-3 Zero bandgap and a fast carrier relaxation process in intrinsic graphene facilitate ultra-broadband and ultrafast light detectors. [4][5][6][7] Under light illumination, graphene with lateral contact electrodes generates photocurrent through a photovoltaic, bolometric, or photo-thermoelectric mechanisms depending on bias and gating conditions. [8][9][10][11][12][13][14][15] Recently, photodetectors based on graphene heterojunctions have been extensively highlighted. Currently, Schottky-barrier-type vertical heterojunctions composed of graphene/silicon, [16][17][18][19][20] reduced-graphene-oxide (RGO)/silicon, 21 and RGO/silicon nanowire 22 have been successfully demonstrated. Unlike lateral photocurrent collection, the vertical junctions take advantage of an asymmetric barrier potential to efficiently separate photoexcited electrons and holes, which might pave the way for light detection with large active areas without the need for external source-drain bias.Here, we demonstrate a heterojunction device capable of dual mode photocurrent collection under zero source-drain bias based on a graphene grown by chemical vapor deposition (CVD) and amorphousphase indium gallium zinc oxide (IGZO). Here, dual mode means that the photocurrent can flow either from a lateral pair of the electrodes or from a vertical pair of electrodes. Versatile photodetection schemes allow to broaden the range of selection for applications such as photoenergy harvesting, phototransistor, and photoconductive detector. 1,2,14 Unlike silicon, IGZO semiconductors can be grown on glass substrates at low temperatures, typically below 200• C so that large area device fabrication is possible. IGZO has been widely used for image sensors, flat-panel displays, and thin film transistors. [23][24][25] The typical mobility of the IGZO film is about 10-60 cm 2 /Vs. 23,25,26 Interes...

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Improvements in the device characteristics of amorphous indium gallium zinc oxide thin-film transistors by Ar plasma treatment

Cited by 338 publications

References 16 publications

Medium Frequency Physical Vapor Deposited Al₂O₃and SiO₂as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Medium Frequency Physical Vapor Deposited Al₂O₃and SiO₂as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Effects of dopants in InOx-based amorphous oxide semiconductors for thin-film transistor applications

Dual Mode Photocurrent Generation of Graphene-Oxide Semiconductor Junction

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Improvements in the device characteristics of amorphous indium gallium zinc oxide thin-film transistors by Ar plasma treatment

Cited by 338 publications

References 16 publications

Medium Frequency Physical Vapor Deposited Al2O3and SiO2as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Medium Frequency Physical Vapor Deposited Al2O3and SiO2as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Effects of dopants in InOx-based amorphous oxide semiconductors for thin-film transistor applications

Dual Mode Photocurrent Generation of Graphene-Oxide Semiconductor Junction

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Medium Frequency Physical Vapor Deposited Al₂O₃and SiO₂as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors

Medium Frequency Physical Vapor Deposited Al₂O₃and SiO₂as Etch-Stop-Layers for Amorphous Indium-Gallium-Zinc-Oxide Thin-Film-Transistors