Electrical and Optical Properties of In<sub>2</sub>O<sub>3</sub>–ZnO Films Deposited on Polyethylene Terephthalate Substrates by Radio Frequency Magnetron Sputtering

Kim, Hwa-Min; Jung, S. H.; Ahn, Jeung Sun; Kang, Young-Jin; Je, Koo–Chul

doi:10.1143/jjap.42.223

Cited by 49 publications

(18 citation statements)

References 5 publications

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“…20,21 These values are quite close to the ones observed on crystalline/polycrystalline films. That is, p O does not affect strongly the optical performances of the films.…”

Section: B Optical and Electrical Characteristicssupporting

confidence: 78%

Role of order and disorder on the electronic performances of oxide semiconductor thin film transistors

Martins

Barquinha

Ferreira

et al. 2007

Journal of Applied Physics

199

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The role of order and disorder on the electronic performances of n-type ionic oxides such as zinc oxide, gallium zinc oxide, and indium zinc oxide used as active (channel) or passive (drain/source) layers in thin film transistors (TFTs) processed at room temperature are discussed, taking as reference the known behavior observed in conventional covalent semiconductors such as silicon. The work performed shows that while in the oxide semiconductors the Fermi level can be pinned up within the conduction band, independent of the state of order, the same does not happen with silicon. Besides, in the oxide semiconductors the carrier mobility is not bandtail limited and so disorder does not affect so strongly the mobility as it happens in covalent semiconductors. The electrical properties of the oxide films (resistivity, carrier concentration, and mobility) are highly dependent on the oxygen vacancies (source of free carriers), which can be controlled by changing the oxygen partial pressure during the deposition process and/or by adding other metal ions to the matrix. In this case, we make the oxide matrix less sensitive to the presence of oxygen, widening the range of oxygen partial pressures that can be used and thus improving the process control of the film resistivity. The results obtained in fully transparent TFT using polycrystalline ZnO or amorphous indium zinc oxide (IZO) as channel layers and highly conductive poly/nanocrystalline ZGO films or amorphous IZO as drain/source layers show that both devices work in the enhancement mode, but the TFT with the highest electronic saturation mobility and on/off ratio 49.9cm2∕Vs and 4.3×108, respectively, are the ones in which the active and passive layers are amorphous. The ZnO TFT whose channel is based on polycrystalline ZnO, the mobility and on/off ratio are, respectively, 26cm2∕Vs and 3×106. This behavior is attributed to the fact that the electronic transport is governed by the s-like metal cation conduction bands, not significantly affected by any type of angular disorder promoted by the 2p O states related to the valence band, or small amounts of incorporated metal impurities that lead to a better control of vacancies and of the TFT off current.

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“…20,21 These values are quite close to the ones observed on crystalline/polycrystalline films. That is, p O does not affect strongly the optical performances of the films.…”

Section: B Optical and Electrical Characteristicssupporting

confidence: 78%

Role of order and disorder on the electronic performances of oxide semiconductor thin film transistors

Martins

Barquinha

Ferreira

et al. 2007

Journal of Applied Physics

199

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“…Amorphous films, which can be deposited at low temperature on flexible substrates, have good mechanical stabilities under stress [3][4][5][6] and smoother surface morphologies. 7 They can, therefore, be explored as an enabling technology for flexible electronics. 7,8 At the same time, a-TCOs have comparable electrical and optical properties to their crystalline counterparts.…”

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confidence: 99%

“…7 They can, therefore, be explored as an enabling technology for flexible electronics. 7,8 At the same time, a-TCOs have comparable electrical and optical properties to their crystalline counterparts. 5,9 Amorphous Zn-Sn-O (a-ZTO) films, besides being indium-free, have shown superior electrical properties than crystalline films along the ZnO-SnO 2 binary (ZnSnO 3 , 10-12 Zn 2 SnO 4 , 10,13,14 Zn-doped SnO 2 , 15 or Sn-doped ZnO [16][17][18].…”

mentioning

confidence: 99%

Structural and physical properties of transparent conducting, amorphous Zn-doped SnO₂ films

Zhu

Buchholz

et al. 2014

Journal of Applied Physics

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“…Finally, it is also known that the thickness of the film also influences the absorption edge. 51 Since there is only a small shift the absorption edge and small change in band gap in our ZTO films, the influence of the film thickness on the band gap is considered insignificant.…”

Section: -mentioning

confidence: 99%

Optimisation of amorphous zinc tin oxide thin film transistors by remote-plasma reactive sputtering

Niang

Cho

Heffernan

et al. 2016

Journal of Applied Physics

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The influence of the stoichiometry of amorphous zinc tin oxide (a-ZTO) thin films used as the semiconducting channel in thin film transistors (TFTs) is investigated. A-ZTO has been deposited using remote-plasma reactive sputtering from zinc:tin metal alloy targets with 10%, 33%, and 50% Sn at. %. Optimisations of thin films are performed by varying the oxygen flow, which is used as the reactive gas. The structural, optical, and electrical properties are investigated for the optimised films, which, after a post-deposition annealing at 500 °C in air, are also incorporated as the channel layer in TFTs. The optical band gap of a-ZTO films slightly increases from 3.5 to 3.8 eV with increasing tin content, with an average transmission ∼90% in the visible range. The surface roughness and crystallographic properties of the films are very similar before and after annealing. An a-ZTO TFT produced from the 10% Sn target shows a threshold voltage of 8 V, a switching ratio of 108, a sub-threshold slope of 0.55 V dec−1, and a field effect mobility of 15 cm2 V−1 s−1, which is a sharp increase from 0.8 cm2 V−1 s−1 obtained in a reference ZnO TFT. For TFTs produced from the 33% Sn target, the mobility is further increased to 21 cm2 V−1 s−1, but the sub-threshold slope is slightly deteriorated to 0.65 V dec−1. For TFTs produced from the 50% Sn target, the devices can no longer be switched off (i.e., there is no channel depletion). The effect of tin content on the TFT electrical performance is explained in the light of preferential sputtering encountered in reactive sputtering, which resulted in films sputtered from 10% and 33% Sn to be stoichiometrically close to the common Zn2SnO4 and ZnSnO3 phases.

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Electrical and Optical Properties of In₂O₃–ZnO Films Deposited on Polyethylene Terephthalate Substrates by Radio Frequency Magnetron Sputtering

Cited by 49 publications

References 5 publications

Role of order and disorder on the electronic performances of oxide semiconductor thin film transistors

Role of order and disorder on the electronic performances of oxide semiconductor thin film transistors

Structural and physical properties of transparent conducting, amorphous Zn-doped SnO₂ films

Optimisation of amorphous zinc tin oxide thin film transistors by remote-plasma reactive sputtering

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Electrical and Optical Properties of In2O3–ZnO Films Deposited on Polyethylene Terephthalate Substrates by Radio Frequency Magnetron Sputtering

Cited by 49 publications

References 5 publications

Role of order and disorder on the electronic performances of oxide semiconductor thin film transistors

Role of order and disorder on the electronic performances of oxide semiconductor thin film transistors

Structural and physical properties of transparent conducting, amorphous Zn-doped SnO2 films

Optimisation of amorphous zinc tin oxide thin film transistors by remote-plasma reactive sputtering

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Product

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Electrical and Optical Properties of In₂O₃–ZnO Films Deposited on Polyethylene Terephthalate Substrates by Radio Frequency Magnetron Sputtering

Structural and physical properties of transparent conducting, amorphous Zn-doped SnO₂ films