4.0-inch Active-Matrix Organic Light-Emitting Diode Display Integrated with Driver Circuits Using Amorphous In–Ga–Zn-Oxide Thin-Film Transistors with Suppressed Variation

Ohara, Hiroki; Sasaki, Toshinari; Noda, K.; Ito, Shunichi; Sasaki, Miyuki; Endo, Yuta; Yoshitomi, Shuhei; Sakata, Junichiro; Serikawa, Tadashi; Yamazaki, Shunpei

doi:10.1143/jjap.49.03cd02

Cited by 59 publications

(40 citation statements)

References 21 publications

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“…Silicon oxide (SiO x ), deposited by plasma-enhanced chemical vapor deposition (PE-CVD), is commonly used as an ES layer for a-IGZO TFTs, since the hydrogen content of SiO x is lower than that of hydrogenated silicon nitride (SiN x :H) deposited by PE-CVD [9]- [13]. However, even for the case of the SiO x ES layer deposited by PE-CVD, a certain amount of hydrogen also diffuses from the ES layer into the a-IGZO channel [14]. It has been reported that hydrogen strongly affects the electrical properties and stability of a-IGZO TFTs.…”

Section: Quantitative Analysis Of the Effect Of Hydrogenmentioning

confidence: 99%

Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In–Ga–Zn–O on Thin-Film Transistor

Toda

Wang²,

Jiang

et al. 2014

IEEE Trans. Electron Devices

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To investigate the effect of hydrogen diffusion from the silicon oxide etch-stopper (SiO x ES) layer into the amorphous In-Ga-Zn-O (a-IGZO) on thin-film transistor (TFT) properties and stabilities, we fabricated a-IGZO TFTs with a SiO x ES layer deposited by plasma-enhanced chemical vapor deposition at various silane (SiH 4 ) partial pressures (P[SiH 4 ]). Then, quantitative analysis was performed to investigate the relationship between the hydrogen content of the a-IGZO and electrical properties and stability of the TFTs. We found that a low resistance region was formed at the backchannel of the TFT, when the SiO x ES layer was deposited at higher P[SiH 4 ], leading to a drastic negative threshold voltage (V th ) shift. In addition, it was also found that at the frontchannel, the increase in the carrier concentration of a-IGZO was proportional to the increase in the amount of hydrogen in a-IGZO. On the other hand, when P[SiH 4 ] was increased, the subthreshold swing, hysteresis, and gate-bias stability of the TFT improved. The results indicate that hydrogen diffused from the SiO x ES layer passivates the electron traps at the a-IGZO and/or gate insulator/a-IGZO interface, and almost all of the hydrogen also acts as shallow-donor in a-IGZO.Index Terms-Amorphous In-Ga-Zn-O (a-IGZO), etchstopper (ES), hydrogen diffusion, silane (SiH 4 ) partial pressure, silicon oxide (SiO x ), thin-film transistor (TFT).

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Section: Quantitative Analysis Of the Effect Of Hydrogenmentioning

confidence: 99%

Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In–Ga–Zn–O on Thin-Film Transistor

Toda

Wang²,

Jiang

et al. 2014

IEEE Trans. Electron Devices

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“…[1][2][3] Oxide-based TFTs have superior advantages because of their high field-effect mobility, 4 excellent uniformity, lowprocessing temperature, 5 and transparency in the visible light. 6 Film properties of oxide materials are drastically influenced by deposition methods and conditions.…”

mentioning

confidence: 99%

Effects of chemical stoichiometry of channel region on bias instability in ZnO thin-film transistors

Kamada

Fujita

Kimura

et al. 2011

Applied Physics Letters

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Demonstration and characterization of an ambipolar high mobility transistor in an undoped GaAs/AlGaAs quantum well Appl. Phys. Lett. 102, 082105 (2013) Investigation of the charge transport mechanism and subgap density of states in p-type Cu2O thin-film transistors Appl. Phys. Lett. 102, 082103 (2013) Negative gate-bias temperature stability of N-doped InGaZnO active-layer thin-film transistors Appl. Phys. Lett. 102, 083505 (2013) A pH sensor with a double-gate silicon nanowire field-effect transistor Appl. Phys. Lett. 102, 083701 (2013) Extrinsic and intrinsic photoresponse in monodisperse carbon nanotube thin film transistors Appl. Phys. Lett. 102, 083104 (2013) Additional information on Appl. Phys. Lett.

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“…During the passivation SiO x layer deposition by PECVD, the plasma causes damage at the a-IGZO/insulator interface since the a-IGZO film is very thin ͑30 nm͒. 10 Therefore, these inferior electrical properties can be attributed to the extra interface states generated during the SiO x deposition process. Figures 2͑a͒ and 2͑b͒ show the illuminated transfer characteristics in a vacuum for the devices without and with SiO x passivation, respectively.…”

mentioning

confidence: 99%

Light-induced instability of an InGaZnO thin film transistor with and without SiOx passivation layer formed by plasma-enhanced-chemical-vapor-deposition

Chen

Chang

Hsieh

et al. 2010

Applied Physics Letters

103

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This paper investigates the illuminated behaviors of InGaZnO thin film transistors with and without a SiO x passivation. For the passivated device, more interface states were generated during SiO x passivation layer deposition by plasma-enhanced-chemical-vapor-deposition. The enhanced trap-assisted photoexcited hole generation induces source side barrier lowering and causes an apparent subthreshold stretch-out phenomenon. However, for the unpassivated device, the fact that the threshold voltage shift in ambient oxygen is lower than in vacuum under light illumination suggests oxygen desorption and readsorption occurs simultaneously, which is consistent with the accelerated recovery rate in oxygen ambiance.Transparent oxide-based thin-film transistors ͑TFTs͒, such as amorphous InGaZnO ͑a-IGZO͒ TFTs, have considerable potential for their possible applications in flat, flexible, and transparent display devices because they offer high mobility, excellent uniformity, good transparency in visible light, and applicability for low-temperature process. 1-4 Although oxide-based TFTs have shown high performance, they have also demonstrated limitations such as instability under light illumination and in different ambient gas. Since most of the proposed uses of the a-IGZO TFT will expose the TFT to a backlight or ambient light during operation, it is necessary to investigate the electrical properties under light illumination and prevent the gas adsorption/desorption onto the exposed back channel layer. 5,6 Recently, many studies have discussed the behavior of ZnO based TFTs under light illumination and illuminated gate bias stress; 7,8 in addition, a passivation layer such as SiO x has been reported to exhibit a good resistance to ambient gas. 9 However, the impact of the SiO x passivation layer for light illumination has not been thoroughly studied, and is worthy of further investigation. In this letter, we investigate the instability under light illumination and discuss the illuminated mechanism for devices with and without a SiO x passivation layer formed by plasmaenhanced-chemical-vapor-deposition ͑PECVD͒. The experiment results suggest different mechanisms occur during illumination for the passivated and unpassivated devices. Furthermore, the illumination behavior of the unpassivated device was examined in vacuum and in O 2 ambiance to analyze the illuminated mechanism.Inverted coplanar a-IGZO TFTs were produced on glass substrate in this work. Briefly, the shaped Ti/Al/Ti ͑50/ 200/50 nm͒ gate electrodes were capped with 300-nm-thick SiO x gate dielectric. The source/drain electrodes were formed with dc-sputtered Ti/Al/Ti ͑50/200/50 nm͒ and then patterned by wet-etching. An active layer of 30-nm-thick a-IGZO film was deposited by a DC magnetron sputtering system using a target of In: Ga: Zn=1:1:1 in atomic ratio. Finally, the passivated device was capped with 200 nm SiO x layer by PECVD. Both the devices were annealed in an oven at 330°C for 2 h. In this work, the threshold voltage ͑V t ͒ is defined as the gate voltage ͑V...

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4.0-inch Active-Matrix Organic Light-Emitting Diode Display Integrated with Driver Circuits Using Amorphous In–Ga–Zn-Oxide Thin-Film Transistors with Suppressed Variation

Cited by 59 publications

References 21 publications

Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In–Ga–Zn–O on Thin-Film Transistor

Quantitative Analysis of the Effect of Hydrogen Diffusion from Silicon Oxide Etch-Stopper Layer into Amorphous In–Ga–Zn–O on Thin-Film Transistor

Effects of chemical stoichiometry of channel region on bias instability in ZnO thin-film transistors

Light-induced instability of an InGaZnO thin film transistor with and without SiOx passivation layer formed by plasma-enhanced-chemical-vapor-deposition

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