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

Aikawa, Satoru; Mitoma, Nobuhiko; Kizu, Takio; Nabatame, Toshihide; Tsukagoshi, Kazuhito

doi:10.1063/1.4921054

Cited by 26 publications

(14 citation statements)

References 57 publications

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“…Doping with metal cations (X = Ga 3+ , Zn 2+ , Si 4+ , Hf 4+ ) to yield ternary or quaternary oxides of formula IXO or IXZO (Z = Zn) is a conventional strategy for In 2 O 3 amorphization, − Such transition and post-transition metal ions with large spherically symmetrical n s-orbitals ( n ≥ 4) provide a dispersive conduction band for electron transport, even in the amorphous state. From Shanmugam’s theory, Lewis acid strength ( L = z / r 2 , where z = the atomic core charge number and r = the ionic radius) and dopant metal-oxide bond dissociation energy ( E M–O ) are key parameters that stabilize MOs against O vacancy formation.…”

Section: Inroductionmentioning

confidence: 99%

Synergistic Boron Doping of Semiconductor and Dielectric Layers for High-Performance Metal Oxide Transistors: Interplay of Experiment and Theory

et al. 2018

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We report the results of a study to enhance metal oxide (MO) thin-film transistor (TFT) performance by doping both the semiconductor (InO) and gate dielectric (AlO) layers with boron (yielding IBO and ABO, respectively) and provide the first quantitative analysis of how B doping affects charge transport in these MO dielectric and semiconducting matrices. The impact of 1-9 atom % B doping on MO microstructure, morphology, oxygen defects, charge transport, and dielectric properties is analyzed together, in detail, by complementary experimental (microstructural, electrical) and theoretical (ab initio MD, DFT) methods. The results indicate that B doping frustrates InO crystallization while suppressing defects responsible for electron trapping and carrier generation. In the adjacent AlO dielectric, B doping increases the dielectric constant and refractive index while reducing leakage currents. Furthermore, optimized solution-processed TFTs combining IBO channels with 6 atom % B and ABO dielectrics with 10 atom % B exhibit field effect mobilities as high as 11 cm V s, current on/off ratios >10, threshold voltages = 0.6 V, and superior bias stress durability.

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Section: Inroductionmentioning

confidence: 99%

Synergistic Boron Doping of Semiconductor and Dielectric Layers for High-Performance Metal Oxide Transistors: Interplay of Experiment and Theory

et al. 2018

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“…Cation doping of gate dielectrics (e.g., La in AlO x ) has been used to mitigate the substantial capacitance–frequency dependence at low frequencies (∼10 Hz) and yields hysteresis-free transistor performance and reliable mobilities . Other than MO cation doping, − anion doping has also been explored to modulate MO properties, especially for MO semiconductors. − Moreover, this laboratory recently found that incorporating fluoride (F) in both the solution-processed semiconductor (InO x ) and dielectric (AlO x ) films promotes metal coordination and impurity removal, leading to high-performance amorphous oxide TFTs . However, we did not explore the details of how anion doping enhances the dielectric stability at low frequencies or study the doping mechanism.…”

Section: Introductionmentioning

confidence: 99%

Frequency-Agile Low-Temperature Solution-Processed Alumina Dielectrics for Inorganic and Organic Electronics Enhanced by Fluoride Doping

et al. 2020

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The frequency-dependent capacitance of low-temperature solution-processed metal oxide (MO) dielectrics typically yields unreliable and unstable thin-film transistor (TFT) performance metrics, which hinders the development of next-generation roll-to-roll MO electronics and obscures intercomparisons between processing methodologies. Here, capacitance values stable over a wide frequency range are achieved in low-temperature combustion-synthesized aluminum oxide (AlO x ) dielectric films by fluoride doping. For an optimal F incorporation of ∼3.7 atomic % F, the F:AlO x film capacitance of 166 ± 11 nF/cm2 is stable over a 10–1–104 Hz frequency range, far more stable than that of neat AlO x films (capacitance = 336 ± 201 nF/cm2) which falls from 781 ± 85 nF/cm2 to 104 ± 4 nF/cm2 over this frequency range. Importantly, both n-type/inorganic and p-type/organic TFTs exhibit reliable electrical characteristics with minimum hysteresis when employing the F:AlO x dielectric with ∼3.7 atomic % F. Systematic characterization of film microstructural/compositional and electronic/dielectric properties by X-ray photoelectron spectroscopy, time-of-fight secondary ion mass spectrometry, cross-section transmission electron microscopy, solid-state nuclear magnetic resonance, and UV–vis absorption spectroscopy reveal that fluoride doping generates AlOF, which strongly reduces the mobile hydrogen content, suppressing polarization mechanisms at low frequencies. Thus, this work provides a broadly applicable anion doping strategy for the realization of high-performance solution-processed metal oxide dielectrics for both organic and inorganic electronics applications.

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“…11(b)]. 119) These results indicate that the TFTs become environmentally stable when using ISO-10 films sputtered with low PO2. Compared with the ISO-3 TFTs, the reliability of the ISO-10 TFTs was significantly improved, although the μi was reduced.…”

Section: Change In the Carrier Transport Mechanismmentioning

confidence: 75%

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

Cited by 26 publications

References 57 publications

Synergistic Boron Doping of Semiconductor and Dielectric Layers for High-Performance Metal Oxide Transistors: Interplay of Experiment and Theory

Synergistic Boron Doping of Semiconductor and Dielectric Layers for High-Performance Metal Oxide Transistors: Interplay of Experiment and Theory

Frequency-Agile Low-Temperature Solution-Processed Alumina Dielectrics for Inorganic and Organic Electronics Enhanced by Fluoride Doping

Si-incorporated amorphous indium oxide thin-film transistors

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