Effect of High-Speed Blade Coating on Electrical Characteristics in Polymer Based Transistors

We explore the effect of high-speed blade coating on electrical characteristics of conjugated polymer-based thin-film transistors (TFTs). As the blade-coating speed increased, the thickness of the polymer thin-film was naturally increased while the surface roughness was found to be unchanged. Polymer TFTs show two remarkable tendencies on the magnitude of field-effect mobility with increasing blade-coating speed. As the blade-coating speed increased up to 2 mm/s, the fieldeffect mobility increased to 4.72 cm2V−1s−1. However, when the coating speed reached 6 mm/s beyond 2 mm/s, the field-effect mobility rather decreased to 3.18 cm2V−1s−1. The threshold voltage was positively shifted from 2.09 to 8.29 V with respect to increase in blade-coating speed.

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Importance of Blade-Coating Temperature for Diketopyrrolopyrrole-based Thin-Film Transistors

Crystals ◽

10.3390/cryst9070346 ◽

2019 ◽

Vol 9 (7) ◽

pp. 346 ◽

Cited By ~ 2

Author(s):

Jun-Ik Park ◽

Hyeon-Seok Jeong ◽

Do-Kyung Kim ◽

Jaewon Jang ◽

In Man Kang ◽

...

Keyword(s):

Thin Film ◽

Thin Film Transistors ◽

Field Effect ◽

Room Temperature ◽

Electrical Performance ◽

Electrical Characteristics ◽

Field Effect Mobility ◽

Donor Acceptor ◽

Coating Temperature ◽

Blade Coating

In this work, the effect of blade-coating temperature on the electrical properties of a conjugated donor–acceptor copolymer containing diketopyrrolopyrrole (DPP)-based thin-film transistors (TFTs) was systematically analyzed. The organic semiconductor (OSC) layers were blade-coated at various blade-coating temperatures from room temperature (RT) to 80 °C. No remarkable changes were observed in the thickness, surface morphology, and roughness of the OSC films as the blade-coating temperature increased. DPP-based TFTs exhibited two noticeable tendencies in the magnitude of field-effect mobility with increasing blade-coating temperatures. As the temperature increased up to 40 °C, the field-effect mobility increased to 148% compared to the RT values. On the contrary, when the temperature was raised to 80 °C, the field-effect mobility significantly reduced to 20.9% of the mobility at 40 °C. These phenomena can be explained by changes in the crystallinity of DPP-based films. Therefore, the appropriate setting of the blade-coating temperature is essential in obtaining superior electrical characteristics for TFTs. A blade-coating temperature of 40 °C was found to be the optimum condition in terms of electrical performance for DPP-based TFTs.

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Numerical Analysis on Effective Mass and Traps Density Dependence of Electrical Characteristics of a-IGZO Thin-Film Transistors

Electronics ◽

10.3390/electronics9010119 ◽

2020 ◽

Vol 9 (1) ◽

pp. 119 ◽

Cited By ~ 3

Author(s):

Jihwan Park ◽

Do-Kyung Kim ◽

Jun-Ik Park ◽

In Man Kang ◽

Jaewon Jang ◽

...

Keyword(s):

Thin Film ◽

Effective Mass ◽

Thin Film Transistors ◽

Field Effect ◽

Electron Mass ◽

Simulation Methods ◽

Electrical Characteristics ◽

Field Effect Mobility ◽

Electron Effective Mass ◽

Amorphous Ingazno

We have investigated the effect of electron effective mass (me*) and tail acceptor-like edge traps density (NTA) on the electrical characteristics of amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs) through numerical simulation. To examine the credibility of our simulation, we found that by adjusting me* to 0.34 of the free electron mass (mo), we can preferentially derive the experimentally obtained electrical properties of conventional a-IGZO TFTs through our simulation. Our initial simulation considered the effect of me* on the electrical characteristics independent of NTA. We varied the me* value while not changing the other variables related to traps density not dependent on it. As me* was incremented to 0.44 mo, the field-effect mobility (µfe) and the on-state current (Ion) decreased due to the higher sub-gap scattering based on electron capture behavior. However, the threshold voltage (Vth) was not significantly changed due to fixed effective acceptor-like traps (NTA). In reality, since the magnitude of NTA was affected by the magnitude of me*, we controlled me* together with NTA value as a secondary simulation. As the magnitude of both me* and NTA increased, µfe and Ion deceased showing the same phenomena as the first simulation. The magnitude of Vth was higher when compared to the first simulation due to the lower conductivity in the channel. In this regard, our simulation methods showed that controlling me* and NTA simultaneously would be expected to predict and optimize the electrical characteristics of a-IGZO TFTs more precisely.

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Spin-on Polymer Gate Dielectric for High Performance Organic Thin Film Transistors

MRS Proceedings ◽

10.1557/proc-558-403 ◽

1999 ◽

Vol 558 ◽

Cited By ~ 30

Author(s):

C.D. Sheraw ◽

D.J. Gundlach ◽

T.N. Jackson

Keyword(s):

Thin Film ◽

Surface Roughness ◽

Thin Film Transistors ◽

Field Effect ◽

Gate Dielectric ◽

Organic Thin Film Transistors ◽

Organic Thin Film ◽

Field Effect Mobility ◽

Parylene C ◽

Polymeric Dielectrics

ABSTRACTWe have investigated the polymeric insulators benzocyclobutene (BCB), parylene C and polyimide for use as gate dielectrics in pentacene organic thin film transistors (TFTs). Atomic force microscopy (AFM) was used to examine the surface roughness of the polymeric dielectrics and the morphology of pentacene films deposited onto them. X-ray diffraction was used to examine the molecular ordering of pentacene films deposited onto the polymeric dielectrics. We find a correlation between the surface roughness of the gate dielectric and the grain size in deposited pentacene films, with smooth surfaces yielding larger, more dendritic grains. Despite significant changes in film morphology, pentacene TFTs using BCB, parylene C, or polyimide as the gate dielectric have performance comparable to devices using SiO2 as the gate dielectric. These results suggest that there is not a strong correlation between pentacene film grain size and field-effect mobility for these devices. Pentacene TFTs using BCB as the gate dielectric had field-effect mobility as high as 0.7 cm2/V-s, on/off ratio > 107, subthreshold slope less than 2 V/decade, and negative threshold voltage, making them an attractive candidate for use in organic-based large-area electronic applications on flexible substrates.

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Effects of order and disorder on field‐effect mobilities measured in conjugated polymer thin‐film transistors

Journal of Applied Physics ◽

10.1063/1.356556 ◽

1994 ◽

Vol 75 (12) ◽

pp. 7954-7957 ◽

Cited By ~ 11

Author(s):

E. R. Holland ◽

D. Bloor ◽

A. P. Monkman ◽

A. Brown ◽

D. De Leeuw ◽

...

Keyword(s):

Thin Film ◽

Conjugated Polymer ◽

Thin Film Transistors ◽

Field Effect ◽

Polymer Thin Film ◽

Order And Disorder

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Improvement in the Positive Bias Temperature Stability of SnOx-Based Thin Film Transistors by Hf and Zn Doping

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2015.11155 ◽

2015 ◽

Vol 15 (10) ◽

pp. 7606-7610 ◽

Cited By ~ 1

Author(s):

Dongsuk Han ◽

Jaehyung Park ◽

Minsoo Kang ◽

Hyeongtag Jeon ◽

Jongwan Park

Keyword(s):

Thin Film ◽

Tin Oxide ◽

Thin Film Transistors ◽

Field Effect ◽

Defect Density ◽

Temperature Stability ◽

Oxidation Potential ◽

Oxide Thin Film ◽

Electrical Characteristics ◽

Field Effect Mobility

We investigated the performance of tin oxide thin film transistors (TFTs) using DC magnetron sputtering. A remarkable improvement in the transfer characteristics was obtained for the Hf-doped tin oxide (HTO) TFT. We also developed amorphous hafnium-zinc-tin oxide (HZTO) thin film transistors and investigated the effects of hafnium doping on the electrical characteristics of the HTO TFTs. Doping with hafnium resulted in a reduced defect density in the tin oxide channel layer related to oxygen vacancies, which may result from increased field effect mobility. Zinc atoms have relatively higher oxidation potential compared to tin atoms, so more oxygen molecules can be absorbed and more electrons are trapped in the HZTO films. The HZTO TFTs exhibited good electrical characteristics with a field effect mobility of 10.98 cm2/Vs, and a high ION/IOFF ratio over 108.

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Effects of Intense Pulsed Light (IPL) Rapid Annealing and Back-Channel Passivation on Solution-Processed In-Ga-Zn-O Thin Film Transistors Array

Micromachines ◽

10.3390/mi11050508 ◽

2020 ◽

Vol 11 (5) ◽

pp. 508 ◽

Cited By ~ 2

Author(s):

Hyun Jae Kim ◽

Chul Jong Han ◽

Byungwook Yoo ◽

Jeongno Lee ◽

Kimoon Lee ◽

...

Keyword(s):

Thin Film ◽

Thin Film Transistors ◽

Field Effect ◽

Annealing Process ◽

Intense Pulsed Light ◽

Electrical Characteristics ◽

Field Effect Mobility ◽

Pulsed Light ◽

Solution Processed ◽

Rapid Annealing

We report on the effects of the intense pulsed light (IPL) rapid annealing process and back-channel passivation on the solution-processed In-Ga-Zn-O (IGZO) thin film transistors (TFTs) array. To improve the electrical properties, stability and uniformity of IGZO TFTs, the oxide channel layers were treated by IPL at atmospheric ambient and passivated by photo-sensitive polyimide (PSPI). When we treated the IGZO channel layer by the IPL rapid annealing process, saturation field effect mobility and subthreshold swing (S.S.) were improved. And, to protect the back-channel of oxide channel layers from oxygen and water molecules, we passivated TFT devices with photo-sensitive polyimide. The IGZO TFTs on glass substrate treated by IPL rapid annealing without PSPI passivation showed the field effect mobility (μFE) of 1.54 cm2/Vs and subthreshold swing (S.S.) of 0.708 V/decade. The PSPI-passivated IGZO TFTs showed higher μFE of 2.17 cm2/Vs than that of device without passivation process and improved S.S. of 0.225 V/decade. By using a simple and fast intense pulsed light treatment with an appropriate back-channel passivation layer, we could improve the electrical characteristics and hysteresis of IGZO-TFTs. We also showed the improved uniformity of electrical characteristics for IGZO TFT devices in the area of 10 × 40 mm2. Since this IPL rapid annealing process could be performed at a low temperature, it can be applied to flexible electronics on plastic substrates in the near future.

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