scholarly journals Effects of Capping Layers with Different Metals on Electrical Performance and Stability of p-Channel SnO Thin-Film Transistors

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 917
Author(s):  
Min-Gyu Shin ◽  
Kang-Hwan Bae ◽  
Hwan-Seok Jeong ◽  
Dae-Hwan Kim ◽  
Hyun-Seok Cha ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Electrical Performance ◽  
Electrical Characteristics ◽  
Field Effect Mobility ◽  
Bias Stress ◽  
Significant Difference ◽  
Channel Potential ◽  
Work Functions ◽  
The Difference

In this study, the effects of capping layers with different metals on the electrical performance and stability of p-channel SnO thin-film transistors (TFTs) were examined. Ni- or Pt-capped SnO TFTs exhibit a higher field-effect mobility (μFE), a lower subthreshold swing (SS), a positively shifted threshold voltage (VTH), and an improved negative-gate-bias-stress (NGBS) stability, as compared to pristine TFTs. In contrast, Al-capped SnO TFTs exhibit a lower μFE, higher SS, negatively shifted VTH, and degraded NGBS stability, as compared to pristine TFTs. No significant difference was observed between the electrical performance of the Cr-capped SnO TFT and that of the pristine SnO TFT. The obtained results were primarily explained based on the change in the back-channel potential of the SnO TFT that was caused by the difference in work functions between the SnO and various metals. This study shows that capping layers with different metals can be practically employed to modulate the electrical characteristics of p-channel SnO TFTs.

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

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 346 ◽  
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.

scholarly journals Improving the electrical performance of solution processed oligothiophene thin-film transistors via structural similarity blending

2017 ◽  
Vol 5 (21) ◽  
pp. 5048-5054 ◽  
Author(s):  
Tim Leydecker ◽  
Laura Favaretto ◽  
Duc Trong Duong ◽  
Gabriella Zappalà ◽  
Karl Börjesson ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Field Effect ◽  
Structural Similarity ◽  
Single Component ◽  
Electrical Performance ◽  
Field Effect Mobility ◽  
Solution Processed

Here we show that the blending of structurally similar oligothiophene molecules is an effective approach to improve the field-effect mobility and Ion/Ioff as compared to single component based transistors.

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

2020 ◽  
Vol 20 (9) ◽  
pp. 5486-5490
Author(s):  
Jun-Ik Park ◽  
Hyun-Seok Jeong ◽  
Premkumar Vincent ◽  
Jihwan Park ◽  
Do-Kyung Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Surface Roughness ◽  
Conjugated Polymer ◽  
Thin Film Transistors ◽  
Field Effect ◽  
High Speed ◽  
Electrical Characteristics ◽  
Field Effect Mobility ◽  
Polymer Thin Film ◽  
Blade Coating

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.

Effect of interfacial InZnO conducting layer on electrical performance and bias stress stability of InAlZnO thin-film transistors

2019 ◽  
Vol 215 ◽  
pp. 111006 ◽  
Author(s):  
Kyoungwan Woo ◽  
Se Hyeong Lee ◽  
Sanghyun Lee ◽  
So-Young Bak ◽  
Yoo-Jong Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Electrical Performance ◽  
Conducting Layer ◽  
Bias Stress

scholarly journals Channel Defect Profiling and Passivation for ZnO Thin-Film Transistors

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1186
Author(s):  
Soo Cheol Kang ◽  
So Young Kim ◽  
Sang Kyung Lee ◽  
Kiyung Kim ◽  
Billal Allouche ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Oxygen Vacancies ◽  
Drain Current ◽  
Vacuum Treatment ◽  
Trap Level ◽  
Zno Thin Film ◽  
Electrical Characteristics ◽  
Bias Stress ◽  
Trap Assisted Tunneling

The electrical characteristics of Zinc oxide (ZnO) thin-film transistors are analyzed to apprehend the effects of oxygen vacancies after vacuum treatment. The energy level of the oxygen vacancies was found to be located near the conduction band of ZnO, which contributed to the increase in drain current (ID) via trap-assisted tunneling when the gate voltage (VG) is lower than the specific voltage associated with the trap level. The oxygen vacancies were successfully passivated after the annealing of ZnO in oxygen ambient. We determined that the trap-induced Schottky barrier lowering reduced a drain barrier when the drain was subjected to negative bias stress. Consequentially, the field effect mobility increased from 8.5 m2 V−1·s−1 to 8.9 m2 V−1·s−1 and on-current increased by ~13%.

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

Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 119 ◽  
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.

scholarly journals Electrical Characteristics and Stability Improvement of Top-Gate In-Ga-Zn-O Thin-Film Transistors with Al2O3/TEOS Oxide Gate Dielectrics

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1146
Author(s):  
Yih-Shing Lee ◽  
Yu-Hsin Wang ◽  
Tsung-Cheng Tien ◽  
Tsung-Eong Hsieh ◽  
Chun-Hung Lai
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Single Layer ◽  
Charge Trapping ◽  
Indium Gallium Zinc Oxide ◽  
Electrical Characteristics ◽  
Electrical Stability ◽  
Bias Stress

In this work, two stacked gate dielectrics of Al2O3/tetraethyl-orthosilicate (TEOS) oxide were deposited by using the equivalent capacitance with 100-nm thick TEOS oxide on the patterned InGaZnO layers to evaluate the electrical characteristics and stability improvement of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) devices, including positive bias stress (PBS) and negative bias stress (NBS) tests. Three different kinds of gate dielectrics (Al2O3, TEOS, Al2O3/TEOS) were used to fabricate four types of devices, differing by the gate dielectric, as well as its thickness. As the Al2O3 thickness of Al2O3/TEOS oxide dielectric stacks increased, both the on-current and off-current decreased, and the transfer curves shifted to larger voltages. The lowest ∆Vth of 0.68 V and ∆S.S. of −0.03 V/decade from hysteresis characteristics indicate that the increase of interface traps and charge trapping between the IGZO channel and gate dielectrics is effectively inhibited by using two stacked dielectrics with 10-nm thick Al2O3 and 96-nm thick TEOS oxide. The lowest ∆Vth and ∆S.S. values of a-IGZO TFTs with 10-nm thick Al2O3 and 96-nm thick TEOS oxide gate dielectrics according to the PBS and NBS tests were shown to have the best electrical stability in comparison to those with the Al2O3 or TEOS oxide single-layer dielectrics.

scholarly journals Electrical Performance and Bias-Stress Stability of Amorphous InGaZnO Thin-Film Transistors with Buried-Channel Layers

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 779
Author(s):  
Ying Zhang ◽  
Haiting Xie ◽  
Chengyuan Dong
Keyword(s):  
Thin Film Transistors ◽  
Field Effect ◽  
Nitrogen Doping ◽  
Electrical Performance ◽  
Field Effect Mobility ◽  
Nitrogen Doped ◽  
Bias Stress ◽  
Channel Layer ◽  
Buried Channel ◽  
Amorphous Ingazno

To improve the electrical performance and bias-stress stability of amorphous InGaZnO thin-film transistors (a-IGZO TFTs), we fabricated and characterized buried-channel devices with multiple-stacked channel layers, i.e., a nitrogen-doped a-IGZO film (front-channel layer), a conventional a-IGZO film (buried-channel layer), and a nitrogen-doped a-IGZO film (back-channel layer). The larger field-effect mobility (5.8 cm2V−1s−1), the smaller subthreshold swing value (0.8 V/dec, and the better stability (smaller threshold voltage shifts during bias-stress and light illumination tests) were obtained for the buried-channel device relative to the conventional a-IGZO TFT. The specially designed channel-layer structure resulted in multiple conduction channels and hence large field-effect mobility. The in situ nitrogen-doping caused reductions in both the front-channel interface trap density and the density of deep states in the bulk channel layers, leading to a small subthreshold swing value. The better stability properties may be related to both the reduced trap states by nitrogen-doping and the passivation effect of the nitrogen-doped a-IGZO films at the device back channels.

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