Reliability improvement of InGaZnO thin film transistors encapsulated under nitrogen ambient

Wu, Chunyu; Cheng, Huang–Chung; Wang, Chao-Lung; Liao, Ta-Chuan; Chiu, Pao‐Hsiung; Tsai, Chih‐Hung; Fang, Chun‐Hsiung; Lee, Chung-Chun

doi:10.1063/1.3702794

Cited by 10 publications

(6 citation statements)

References 18 publications

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“…The use of N 2 annealing is due to the improvement of TFT properties as has been reported for IGZO. 72,73) In this case, the In 2 O 3 /WO 3 ratio in the IWO target was 99/1 wt%. The root mean square (RMS) roughness measured was 0.27 nm, indicating that the surface was almost as flat as the Si substrate (0.24 nm).…”

Section: W-doping Using Acid Insoluble Womentioning

confidence: 79%

“…In contrast, adsorbing oxygen from the ambient atmosphere reduces carrier concentration due to the charge transfer. 73,118,[131][132][133] The effect of oxygen adsorption is also reflected in the shift in E F from above to below E m , as shown in Fig. 12(b), and then, the I-V characteristics of the vacuum storage TFTs are recovered.…”

Section: Change In the Carrier Transport Mechanismmentioning

confidence: 94%

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Si-incorporated amorphous indium oxide thin-film transistors

Aikawa

Nabatame

Tsukagoshi

2019

Jpn. J. Appl. Phys.

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Amorphous oxide semiconductors, especially indium oxide-based (InOx) thin-films, have been major candidates for high mobility with easy-to-use device processability. As one of the dopants in InOx semiconductors, we proposed Si to design a thin-film transistor (TFT) channel. Because the suppression of unstable oxygen vacancies in InOx is crucial to maintaining the semiconducting behavior, Si was selected as a strong oxygen binder that is reasonably available for large production. In this review, we focus on the overall properties observed in Si-incorporated amorphous InOx TFTs in terms of bond-dissociation energy, Gibbs free energy, Si-concentration dependence of TFT properties, carrier transport mechanism, and bias stress instability. In comparing low and high doping densities, we found that the activation energy and density of states decreased at a high Si concentration in InOx TFTs, implying that the trap density was reduced. As a result, stable operation under bias stresses could be realized. Furthermore, the inverse Meyer-Neldel rule was observed in the highlySi-doped InOx TFT, indicating reasonable ohmic contact. Based on our fundamental knowledge of the Template for JJAP Regular Papers (Jan. 2014) 2Si-doped InOx film, we developed a high-mobility bilayer TFT with a homogeneous stacked channel that was different from a TFT with an etch stop layer structure. The TFT showed remarkably stable operation. With simple element components based on InOx, it is possible to systematically discuss vacancy engineering in terms of conduction properties.

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Section: W-doping Using Acid Insoluble Womentioning

confidence: 79%

Section: Change In the Carrier Transport Mechanismmentioning

confidence: 94%

Si-incorporated amorphous indium oxide thin-film transistors

Aikawa

Nabatame

Tsukagoshi

2019

Jpn. J. Appl. Phys.

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“…It can be seen that ΔV th increased with stress time. The V th shift by PGBS is mainly ascribed to the influence of absorbed oxygen molecules reacting on the surface, which can be expressed in the form of O 2 (gas) + e -→ 2O -(solid) [13]. When a positive gate bias was applied to the a-IGZO film, the conduction electrons (e -) were extracted by the surrounding oxygen molecules, resulting in increased negatively charged oxygen (O 2 -) adsorption on the surface.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, a negative shift of V th with increasing negative bias stressing time is attributed to the film defects, interface charge traps, and neutral oxygen vacancies serving as electron donors. (O II ) is typically associated with the presence of oxygendeficient regions or loosely bound oxygen on the surface, attributed to H 2 O and OH groups incorporated into the materials [13,14]. The ratio of the peak area O II /O I + O II , which indicates the relative quantity of the oxygenrelated defects, decreased from 32.1% (for conventional furnace annealing) to 27.6% (for microwave irradiation).…”

Section: Resultsmentioning

confidence: 99%

Improvement of Device Characteristic on Solution-Processed InGaZnO Thin-Film-Transistor (TFTs) using Microwave Irradiation

Moon¹,

Cho²

2015

JSTS:Journal of Semiconductor Technology and Science

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Abstract-Solution-derivedamorphous indiumgallium-zinc oxide (a-IGZO) thin-film-transistor (TFTs) were developed using a microwave irradiation treatment at low process temperature below 300°C. Compared to conventional furnace-annealing, the a-IGZO TFTs annealed by microwave irradiation exhibited better electrical characteristics in terms of field effect mobility, SS, and on/off current ratio, although the annealing temperature of microwave irradiation is much lower than that of furnace annealing. The microwave irradiated TFTs showed a smaller V th shift under the positive gate bias stress (PGBS) and negative gate bias stress (NGBS) tests owing to a lower ratio of oxygen vacancies, surface absorbed oxygen molecules, and reduced interface trapping in a-IGZO. Therefore, microwave irradiation is very promising to low-temperature process.

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“…In contrast, adsorbing oxygen from the ambient atmosphere reduces carrier concentration, as previously discussed. 28,[38][39][40][41] The effect of oxygen adsorption is also reflected that E F shifts from above to below E m , as shown in Fig. 3(b), then the I-V characteristics of the vacuum storage TFTs are recovered.…”

mentioning

confidence: 91%

Suppression of excess oxygen for environmentally stable amorphous In-Si-O thin-film transistors

Aikawa

Mitoma

Kizu

et al. 2015

Applied Physics Letters

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We discuss the environmental instability of amorphous indium oxide (InO x )-based thin-film transistors (TFTs) in terms of the excess oxygen in the semiconductor films. A comparison between amorphous InO x doped with low and high concentrations of oxygen binder (SiO 2 ) showed that out-diffusion of oxygen molecules causes drastic changes in the film conductivity and TFT turn-on voltages. Incorporation of sufficient SiO 2 could suppress fluctuations in excess oxygen because of the high oxygen bond-dissociation energy and low Gibbs free energy. Consequently, the TFT operation became rather stable. The results would be useful for the design of reliable oxide TFTs with stable electrical properties.

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Reliability improvement of InGaZnO thin film transistors encapsulated under nitrogen ambient

Cited by 10 publications

References 18 publications

Si-incorporated amorphous indium oxide thin-film transistors

Si-incorporated amorphous indium oxide thin-film transistors

Improvement of Device Characteristic on Solution-Processed InGaZnO Thin-Film-Transistor (TFTs) using Microwave Irradiation

Suppression of excess oxygen for environmentally stable amorphous In-Si-O thin-film transistors

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