Effect of high-pressure oxygen annealing on negative bias illumination stress-induced instability of InGaZnO thin film transistors

Ji, Kwang Hwan; Kim, Ji In; Jung, Hong Yoon; Park, Se Yeob; Choi, Rino; Kim, Un Ki; Hwang, Cheol Seong; Lee, Daeseok; Hwang, Hyungsang; Jeong, Jae Kyeong

doi:10.1063/1.3564882

Cited by 266 publications

(142 citation statements)

References 18 publications

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“…45 The tail states or undercoordinated cations are intrinsic to the amorphous phase, and hence difficult to suppress unless the material composition is changed. One viable approach would be to increase the optical gap by increasing the atomic density of the amorphous film through compressive strain or dopants.…”

mentioning

confidence: 99%

Intrinsic nature of visible-light absorption in amorphous semiconducting oxides

Kang¹,

Song²,

Nahm³

et al. 2014

APL Materials

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To enlighten microscopic origin of visible-light absorption in transparent amorphous semiconducting oxides, the intrinsic optical property of amorphous InGaZnO4 is investigated by considering dipole transitions within the quasiparticle band structure. In comparison with the crystalline InGaZnO4 with the optical gap of 3.6 eV, the amorphous InGaZnO4 has two distinct features developed in the band structure that contribute to significant visible-light absorption. First, the conduction bands are down-shifted by 0.55 eV mainly due to the undercoordinated In atoms, reducing the optical gap between extended states to 2.8 eV. Second, tail states formed by localized oxygen p orbitals are distributed over ∼0.5 eV near the valence edge, which give rise to substantial subgap absorption. The fundamental understanding on the optical property of amorphous semiconducting oxides based on underlying electronic structure will pave the way for resolving instability issues in recent display devices incorporating the semiconducting oxides.

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mentioning

confidence: 99%

Intrinsic nature of visible-light absorption in amorphous semiconducting oxides

Kang¹,

Song²,

Nahm³

et al. 2014

APL Materials

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“…[1][2][3][4][5] However, there are still many issues related to the control of threshold voltage and bias-induced degradation. [6][7][8][9][10][11] Therefore, there have been many studies on improving AOS TFT stability such as high-pressure oxygen annealing, 12 annealing in hydrogen environment, 13 O 2 plasma treatment, 14 suitable passivation materials, 15 long channel TFT 16 and long-time annealing, etc. 17 Especially, the performance of a-IGZO TFT depends on channel length, and the TFTs with channel length less than 2 µm exhibit mostly depletion mode behavior.…”

mentioning

confidence: 99%

Control of O-H bonds at a-IGZO/SiO2 interface by long time thermal annealing for highly stable oxide TFT

Jeon

Lee

et al. 2017

AIP Advances

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We report two-step annealing, high temperature and sequent low temperature, for amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) to improve its stability and device performance. The annealing is carried out at 300 oC in N2 ambient for 1 h (1st step annealing) and then at 250 oC in vacuum for 10 h (2nd step annealing). It is found that the threshold voltage (VTH) changes from 0.4 V to -2.0 V by the 1st step annealing and to +0.6 V by 2nd step annealing. The mobility changes from 18 cm2V-1s-1 to 25 cm2V-1s-1 by 1st step and decreases to 20 cm2V-1s-1 by 2nd step annealing. The VTH shift by positive bias temperature stress (PBTS) is 3.7 V for the as-prepared TFT, and 1.7 V for the 1st step annealed TFT, and 1.3 V for the 2nd step annealed TFT. The XPS (X-ray photoelectron spectroscopy) depth analysis indicates that the reduction in O-H bonds at the top interface (SiO2/a-IGZO) by 2nd step annealing appears, which is related to the positive VTH shift and smaller VTH shift by PBTS.

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“…In addition, low-permeable passivation layers (such as Al 2 O 3 and SiON x ) resulted in better device stability, even under stress conditions [159]. Furthermore, it was revealed that robust oxide semiconductors normally contain higher oxygen content during the deposition process and post treatment [160,161]. In summary, in terms of materials and structures, stable and reliable oxide TFTs have less hydrogen and higher oxygen composition to suppress V th shifts when exposed to the four practical stress conditions.…”

Section: Stable and Reliable Oxide Tftsmentioning

confidence: 99%

“…In order to improve the stability of oxide TFTs, researchers have suggested various methods including optimized structures [82], suitable gate insulator materials [158], impermeable passivation layers [159], robust semiconductors [160] 3)BZN(0.7) (a) (b) (c) Fig. 18 (a) and post-annealing treatments [161]. For instance, by comparing bottom-gate TFTs with a back-channel-etch (BCE) or an etch-stop (ES) structure, researchers found that the stability of an ES-type device was superior to that of a BCE type device, which may be attributable to the formation of defective interfacial layers [82].…”

Section: Stable and Reliable Oxide Tftsmentioning

confidence: 99%

Overview of electroceramic materials for oxide semiconductor thin film transistors

2013

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The flat panel display (FPD) market has been experiencing a rapid transition from liquid crystal (LC) to organic light emitting diode (OLED) displays, leading, in turn, to the accelerated commercialization of OLED televisions already in 2013. The major driving force for this rapid change was the adaptation of novel oxide semiconductor materials as the active channel layer in thin film transistors (TFTs). Since the report of amorphous-InGaZnO (a-IGZO) semiconductor materials in 2004, the FPD industry has accelerated the development of oxide TFTs for mass-production. In this review, we focus on recent progress in applying electro-ceramic materials for oxidesemiconductor thin-film-transistors. First, oxide-based semiconductor materials, distinguished by vacuum or solution processing, are discussed, with efforts to develop high-performance, cost-effective devices reviewed in chronological order. The introduction and role of high dielectric constant -reduced leakage gate insulators, in optimizing oxide-semiconductor device performance, are next covered. We conclude by discussing current issues impacting oxide-semiconductor TFTs, such as field effect mobility and device stability and the proposed directions being taken to address them.

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Effect of high-pressure oxygen annealing on negative bias illumination stress-induced instability of InGaZnO thin film transistors

Cited by 266 publications

References 18 publications

Intrinsic nature of visible-light absorption in amorphous semiconducting oxides

Intrinsic nature of visible-light absorption in amorphous semiconducting oxides

Control of O-H bonds at a-IGZO/SiO2 interface by long time thermal annealing for highly stable oxide TFT

Overview of electroceramic materials for oxide semiconductor thin film transistors

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