Analysis of <i>amorphous</i> indium-gallium-zinc-oxide thin-film transistor contact metal using Pilling-Bedworth theory and a variable capacitance diode model

Kiani, Ahmed; Hasko, D. G.; Milne, W. I.; Flewitt, Andrew J.

doi:10.1063/1.4801991

Cited by 22 publications

(14 citation statements)

References 26 publications

(30 reference statements)

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“…Next, as shown in Figure b,c, I D increases very little, only 0.15×, when L is increased 25×. These are consistent with the properties of SGTs that the device is controlled by the source region ( S ) and is less sensitive to L . This is an advantage over conventional TFTs where the drain current is affected by the shorter channel and thus is susceptible to device‐to‐device fluctuations due to fabrication variability .…”

Section: Structural and Electrical Characteristics Of Source‐gated Trsupporting

confidence: 78%

“…The depletion‐mode, normally‐on operation of the device indicates a channel conductivity much higher than the ideal. The deposited IGZO films have a carrier concentration ≈10 19 cm −3 with Hall mobility ≈10 cm 2 V −1 s −1 and they have been previously incorporated as the active layer in bottom gate TFTs . However, as shown in this work, these films become too conductive when used in top gate transistors.…”

Section: Structural and Electrical Characteristics Of Source‐gated Trmentioning

confidence: 82%

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Novel Tunnel‐Contact‐Controlled IGZO Thin‐Film Transistors with High Tolerance to Geometrical Variability

et al. 2019

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Thin insulating layers are used to modulate a depletion region at the source of a thin‐film transistor. Bottom contact, staggered‐electrode indium gallium zinc oxide transistors with a 3 nm Al2O3 layer between the semiconductor and Ni source/drain contacts, show behaviors typical of source‐gated transistors (SGTs): low saturation voltage (VD_SAT ≈ 3 V), change in VD_SAT with a gate voltage of only 0.12 V V−1, and flat saturated output characteristics (small dependence of drain current on drain voltage). The transistors show high tolerance to geometry: the saturated current changes only 0.15× for 2–50 µm channels and 2× for 9‐45 µm source‐gate overlaps. A higher than expected (5×) increase in drain current for a 30 K change in temperature, similar to Schottky‐contact SGTs, underlines a more complex device operation than previously theorized. Optimization for increasing intrinsic gain and reducing temperature effects is discussed. These devices complete the portfolio of contact‐controlled transistors, comprising devices with Schottky contacts, bulk barrier, or heterojunctions, and now, tunneling insulating layers. The findings should also apply to nanowire transistors, leading to new low‐power, robust design approaches as large‐scale fabrication techniques with sub‐nanometer control mature.

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Section: Structural and Electrical Characteristics Of Source‐gated Trsupporting

confidence: 78%

Section: Structural and Electrical Characteristics Of Source‐gated Trmentioning

confidence: 82%

Novel Tunnel‐Contact‐Controlled IGZO Thin‐Film Transistors with High Tolerance to Geometrical Variability

et al. 2019

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“…Conducting metal oxides, such as antimony tin oxide (ATO) and indium tin oxide (ITO), are challenging to process at low temperatures from solution by conventional sol-gel techniques with adequate electrical conductivity. 16, [23][24][25] In contrast, silver is the most prevalent inkjet-printed conductor, with silver nanoparticle or molecular precursor inks widely used due to their resistance to oxidation, low temperature sintering compatibility, and high electrical conductivity. 26 Consequently, to develop printed source/drain electrodes for IGZO TFTs, in this contribution we first assess the suitability of a commercial silver nanoparticle ink.…”

Section: Introductionmentioning

confidence: 95%

High-Performance Inkjet-Printed Indium-Gallium-Zinc-Oxide Transistors Enabled by Embedded, Chemically Stable Graphene Electrodes

Secor¹,

Smith²,

Marks

et al. 2016

ACS Appl. Mater. Interfaces

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Recent developments in solution-processed amorphous oxide semiconductors have established indium-gallium-zinc-oxide (IGZO) as a promising candidate for printed electronics. A key challenge for this vision is the integration of IGZO thin-film transistor (TFT) channels with compatible source/drain electrodes using low-temperature, solution-phase patterning methods. Here we demonstrate the suitability of inkjet-printed graphene electrodes for this purpose. In contrast to common inkjet-printed silver-based conductive inks, graphene provides a chemically stable electrode-channel interface. Furthermore, by embedding the graphene electrode between two consecutive IGZO printing passes, high-performance IGZO TFTs are achieved with an electron mobility of ∼6 cm(2)/V·s and current on/off ratio of ∼10(5). The resulting printed devices exhibit robust stability to aging in ambient as well as excellent resilience to thermal stress, thereby offering a promising platform for future printed electronics applications.

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“…The IGZO deposition conditions were previously optimised to produce thin film transistors with a high mobility, low threshold voltage and large switching ratio. Examples of TFT characteristics have been reported previously in [15].…”

Section: Methodsmentioning

confidence: 99%

Mechanical properties of amorphous indium–gallium–zinc oxide thin films on compliant substrates for flexible optoelectronic devices

et al. 2015

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Amorphous indium-gallium-zinc-oxide (a-IGZO) thin films were deposited using RF magnetron sputtering on polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) flexible substrates and their mechanical flexibility investigated using uniaxial tensile and buckling tests coupled with in situ optical microscopy. The uniaxial fragmentation test demonstrated that the crack onset strain of the IGZO/PEN was ~2.9%, which is slightly higher than that of IGZO/PET. Also, uniaxial tensile crack density analysis suggests that the saturated crack spacing of the film is strongly dependent on the mechanical properties of the underlying polymer substrate. Buckling test results suggest that the crack onset strain (equal to ~ 1.2%, of the IGZO/polymer samples flexed in compression to ~ 5.7 mm concave radius of curvature) is higher than that of the samples flexed with the film being in tension (convex bending) regardless whether the substrate is PEN or PET. The saturated crack density of a-IGZO film under the compression buckling mode is smaller than that of the film under the tensile buckling mode. This could be attributed to the fact that the tensile stress encouraged this crack formation originating from surface defects in the coating. It could also be due to the buckling delamination of the thin coating from the substrate at a lower strain than that at which a crack initiates during flexing in compression. These results provide useful information on the mechanical reliability of a-IGZO films for the development of flexible electronics.

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Analysis of amorphous indium-gallium-zinc-oxide thin-film transistor contact metal using Pilling-Bedworth theory and a variable capacitance diode model

Cited by 22 publications

References 26 publications

Novel Tunnel‐Contact‐Controlled IGZO Thin‐Film Transistors with High Tolerance to Geometrical Variability

Novel Tunnel‐Contact‐Controlled IGZO Thin‐Film Transistors with High Tolerance to Geometrical Variability

High-Performance Inkjet-Printed Indium-Gallium-Zinc-Oxide Transistors Enabled by Embedded, Chemically Stable Graphene Electrodes

Mechanical properties of amorphous indium–gallium–zinc oxide thin films on compliant substrates for flexible optoelectronic devices

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