69.2: Highly Reliable Oxide‐Semiconductor TFT for AM‐OLED Display

Arai, Toshiaki; Morosawa, Narihiro; Tokunaga, Kazuhiko; Terai, Yasuhiro; Fukumoto, Eri; Fujimori, Takahiro; Nakayama, Tetsuo; Yamaguchi, Takashi; Sasaoka, Tatsuya

doi:10.1889/1.3499825

Cited by 79 publications

(45 citation statements)

References 5 publications

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“…The estimated absolute uncertainties on the reported values are ∼ 0.5 at.%. From the graph [15][16] or as dopant blocking layer, 21 little explanation around the NBS and PBS is provided. In our previous work; we compared the mf-PVD SiO 2 ESL based TFT characteristics and their bias-stress stabilities (PBS and NBS) to high temperature (300…”

Section: Resultsmentioning

confidence: 99%

“…[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 alternative to PECVD layer which has the doping issue with a-IGZO. 15,16,22 Despite the fact that PVD dielectrics intrinsically contain less hydrogen, parameters such as deposition rates, uniformity, defect density and electrical properties like leakage current and breakdown voltage are often insufficient to meet the manufacturing requirements of the industry. Recently mf-PVD Al 2 O 3 layers have been demonstrated with high deposition rate and sufficient uniformity up to Gen-8 size.…”

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confidence: 99%

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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%

mentioning

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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“…On the other hand, the SIMS depth profile for the Cu/Ti/IGZOstacked film shows that Ga atoms diffused into the Cu film ( Figure 5), and that the homogeneity of the IGZO layer totally deteriorated. According to Arai et al [8], the Ti/IGZO interfacial redox reaction deteriorates the in-plane uniformity in the IGZO TFT transfer curves. These TEM and SIMS results indicate that the Ti/Si barrier layer suppresses any defect formation due to the interfacial reaction and the interdiffusion between the oxide semiconductor and the barrier layer.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, Ti often reacts with the oxide semiconductors at the interface, resulting in a reduction of the elements in the oxide semiconductors [8][9][10]. Thus, the barrier layer that meets the above-mentioned criteria is strongly desired.…”

Section: Introductionmentioning

confidence: 99%

Facilitation of the four-mask process by the double-layered Ti/Si barrier metal for oxide semiconductor TFTs

Hino

Maeda

Morita

et al. 2012

Journal of Information Display

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The double-layered Ti/Si barrier metal is demonstrated for the source/drain Cu interconnections in oxide semiconductor thin-film transistors (TFTs). The transmission electromicroscopy and ion mass spectroscopy analyses revealed that the doublelayered barrier structure suppresses the interfacial reaction and the interdiffusion at the interface after thermal annealing at 350 • C. The underlying Si layer was found to be very useful for the etch stopper during wet etching for the Cu/Ti layers. The oxide TFTs with a double-layered Ti/Si barrier metal possess excellent TFT characteristics. It is concluded that the present barrier structure facilitates the back-channel-etch-type TFT process in the mass production line, where the four-or five-mask process is used.

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“…Indium-Gallium-Zinc-Oxide (IGZO) is a common material used as active channel material by display manufacturers to serve this new market [1][2]. But as reported by Arai et al [3] and Morosawa et al [4] special protection of the active layer is needed to ensure longtime-stability under stressed conditions. An additional sputtered Al 2 O 3 barrier layer was shown to provide the required device stability.…”

Section: Introductionmentioning

confidence: 99%

46.5L: Late‐News Paper: Large Area Sputtered Al₂O₃ Films for High Mobility AM‐TFT Backplanes on PVD Array System PiVot 55kVi²

Kloeppel

Liu

Scheer

2013

Symp Digest of Tech Papers

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69.2: Highly Reliable Oxide‐Semiconductor TFT for AM‐OLED Display

Cited by 79 publications

References 5 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

Facilitation of the four-mask process by the double-layered Ti/Si barrier metal for oxide semiconductor TFTs

46.5L: Late‐News Paper: Large Area Sputtered Al₂O₃ Films for High Mobility AM‐TFT Backplanes on PVD Array System PiVot 55kVi²

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69.2: Highly Reliable Oxide‐Semiconductor TFT for AM‐OLED Display

Cited by 79 publications

References 5 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

Facilitation of the four-mask process by the double-layered Ti/Si barrier metal for oxide semiconductor TFTs

46.5L: Late‐News Paper: Large Area Sputtered Al2O3 Films for High Mobility AM‐TFT Backplanes on PVD Array System PiVot 55kVi2

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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

46.5L: Late‐News Paper: Large Area Sputtered Al₂O₃ Films for High Mobility AM‐TFT Backplanes on PVD Array System PiVot 55kVi²