Oxygen Partial Pressure Impact on Characteristics of Indium Titanium Zinc Oxide Thin Film Transistor Fabricated via RF Sputtering

Hsu, Min‐Huei; Chang, Shoou Jinn; Wu, Wei; Li, Jyun Yi

doi:10.3390/nano7070156

Cited by 15 publications

(6 citation statements)

References 30 publications

(27 reference statements)

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“…The smallest subthreshold swing was achieved in TFT-100, thus suggesting that V GS can readily modulate the I DS in the TFTs with 100% oxygen. The maximum trap-state density (N t ) of the channel layer can be deduced from the subthreshold swing and expressed as follows [43,44]:…”

Section: Resultsmentioning

confidence: 99%

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations

Hwang,

Hsu

2023

Nanotechnology

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Zinc oxide (ZnO)-based thin-film transistors (TFTs) have attracted increasing attention towards flat-panel displays as alternatives to silicon-based TFTs due to their transparency to visible light. Magnesium oxide (MgO) has a wide bandgap (7.8 eV) and high dielectric constant (k). This leads to the development of TFTs using MgO as a gate oxide layer, which can significantly reduce the operating voltage. However, the electrical properties and dielectric constant of MgO are determined from the percentage of oxygen in MgO. In this study, a MgO gate-oxide was deposited on ZnO by magnetron sputtering at various oxygen concentrations (0, 66, and 100%) to fabricate TFTs. With an increase in the oxygen concentration, the oxygen vacancies of MgO were compensated, thereby improving the crystallinity and enhancing the dielectric constant from 6.53 to 12.9 for the oxygen concentrations of 0 and 100%. No pinch-off (saturation) behavior was observed in the TFTs with 0% oxygen; however, the pinch-off voltages were significantly reduced to 17 and 2 V in the TFTs with 66 and 100% oxygen, respectively; hence, the TFT-100 could be operated at a low operating voltage (2V). With an increase in oxygen from 0 to 100%, the threshold voltage and trap-state density significantly decreased from -159 V and 1.6 × 1018 cm−3 to -31.4 V and 6.5 × 1016 cm−3, respectively. The TFTs with 0% oxygen exhibited a higher field-effect mobility of 12 cm2/V-s due to the uncompensated oxygen vacancy in ZnO, which had a higher electron concentration. After introducing oxygen atoms, the field-effect mobility decreased to 0.16 cm2/V-s in the TFTs with 66% oxygen, which can be attributed to the compensated oxygen vacancy and lower electron concentration. In contrast, the field-effect mobility increased to 1.88 cm2/V-s for the TFTs with 100% oxygen due to the enhanced dielectric constant and crystallinity of MgO.

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Section: Resultsmentioning

confidence: 99%

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations

Hwang,

Hsu

2023

Nanotechnology

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“…The electrical characteristics of the OFETs were carried out with a Keithley 4200 sourcemeter (Keithley, Cleveland, OH, USA) in nitrogen at room temperature. Charge carrier mobility ( µ ) and threshold voltage ( V T ) were extracted in the saturation regime from the highest slope of | I DS | 1/2 vs. V GS plots using the following Equation [ 29 ]: I DS = ( W /2 L ) µC ( V GS − V T ) 2 , where L (100 µm) is the channel length, W (1 cm) is the channel width, C is the capacitance (per unit area) of the dielectric, V GS is the gate voltage, and I DS is the drain-source current.…”

Section: Methodsmentioning

confidence: 99%

Effect of Vertical Annealing on the Nitrogen Dioxide Response of Organic Thin Film Transistors

et al. 2018

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Nitrogen dioxide (NO2) sensors based on organic thin-film transistors (OTFTs) were fabricated by conventional annealing (horizontal) and vertical annealing processes of organic semiconductor (OSC) films. The NO2 responsivity of OTFTs to 15 ppm of NO2 is 1408% under conditions of vertical annealing and only 72% when conventional annealing is applied. Moreover, gas sensors obtained by vertical annealing achieve a high sensing performance of 589% already at 1 ppm of NO2, while showing a preferential response to NO2 compared with SO2, NH3, CO, and H2S. To analyze the mechanism of performance improvement of OTFT gas sensors, the morphologies of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene) films were characterized by atomic force microscopy (AFM) in tapping mode. The results show that, in well-aligned TIPS-pentacene films, a large number of effective grain boundaries inside the conducting channel contribute to the enhancement of NO2 gas sensing performance.

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“…13) Various metal cations with small radius and high bond-dissociation energy (BDE) with oxygen, such as Al, Ti, W, etc, or suitable atoms such as Si and N, or metal oxides such as Al 2 O 3 , TiO 2 , SnO 2 , etc, in the α-IGZO channel to reduce oxygen vacancy density, suppress the variation in the density of V o , and improve the quality of the interface between the channel layer and the gate dielectric were also reported. [13][14][15][16][17][18][19][20] TFTs with enhanced carrier mobility and reliability were successfully demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Enhanced electrical performance and reliability of Ti-IGZO thin-film transistors with Hf_1-xAl_xO gate dielectrics

You¹,

Wang²,

Ko³

et al. 2020

Jpn. J. Appl. Phys.

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A thin-film transistor (TFT) with a Ti-IGZO channel layer and Hf1-xAlxO gate dielectric is proposed to improve the performance and reliability of the device. The experimental results show that in three types of TFTs based on HfO2/IGZO, Hf1-xAlxO/IGZO and Hf1-xAlxO/Ti-IGZO gate dielectric/channel structures, the Hf0.88Al0.12O/Ti (2.0%)-IGZO TFT exhibits the best device performance with the subthreshold swing of 86 mV dec−1, field-effect mobility of 28.63 cm2∙V−1∙s−1 and on/off current ratio of 3.26 × 108. In particular, it shows a hysteresis voltage as low as 0.02 V and a threshold voltage shift after 1000 s positive/negative gate bias stress/white light illumination of 0.134 V/−0.089 V/−0.195 V, compared with 0.45 V and 0.612 V/−0.507 V/−0.657 V of the HfO2/IGZO TFT. These improvements are due to the incorporation of Ti into the IGZO channel, which reduces defect density, while adding Al to HfO2 improves surface roughness to inhibit surface scattering and charge capture during stress testing.

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Oxygen Partial Pressure Impact on Characteristics of Indium Titanium Zinc Oxide Thin Film Transistor Fabricated via RF Sputtering

Cited by 15 publications

References 30 publications

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations

Effect of Vertical Annealing on the Nitrogen Dioxide Response of Organic Thin Film Transistors

Enhanced electrical performance and reliability of Ti-IGZO thin-film transistors with Hf_1-xAl_xO gate dielectrics

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Oxygen Partial Pressure Impact on Characteristics of Indium Titanium Zinc Oxide Thin Film Transistor Fabricated via RF Sputtering

Cited by 15 publications

References 30 publications

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations

Improving the electrical properties of transparent ZnO-based thin- film transistors using MgO gate dielectric with various oxygen concentrations

Effect of Vertical Annealing on the Nitrogen Dioxide Response of Organic Thin Film Transistors

Enhanced electrical performance and reliability of Ti-IGZO thin-film transistors with Hf1-xAlxO gate dielectrics

Contact Info

Product

Resources

About

Enhanced electrical performance and reliability of Ti-IGZO thin-film transistors with Hf_1-xAl_xO gate dielectrics