scholarly journals Enhancement of Electrical Characteristics and Stability of Amorphous Si-Sn-O Thin Film Transistors with SiOx Passivation Layer

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1440 ◽  
Author(s):  
Xianzhe Liu ◽  
Weijing Wu ◽  
Weifeng Chen ◽  
Honglong Ning ◽  
Xiaochen Zhang ◽  
...  
Keyword(s):  
Thin Film ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Charge Trapping ◽  
Passivation Layer ◽  
Device Performance ◽  
Electrical Characteristics ◽  
Initial State ◽  
Large Size ◽  
Amorphous Si

In this research, a passivated methodology was proposed for achieving good electrical characteristics for back-channel-etch (BCE) typed amorphous Si-Sn-O thin film transistors (a-STO TFTs). This methodology implied that the thermal annealing (i.e., pre-annealing) should be carried out before deposition of a SiOx passivation layer. The pre-annealing played an important role in affecting device performance, which did get rid of the contamination of the lithography process. Simultaneously, the acceptor-like sub-gap density of states (DOS) of devices was extracted for further understanding the reason for improving device performance. It found that the SiOx layer could reduce DOS of the device and successfully protect the device from surroundings. Finally, a-STO TFT applied with this passivated methodology could possess good electrical properties including a saturation mobility of 4.2 ± 0.2 cm2/V s, a low threshold voltage of 0.00 V, a large on/off current ratio of 6.94 × 108, and a steep subthreshold swing of 0.23 V/decade. The threshold voltage slightly shifted under bias stresses and recovered itself to its initial state without any annealing procedure, which was attributed to the charge trapping in the bulk dielectric layers or interface. The results of this study indicate that a-STO TFT could be a robust candidate for realizing a large-size and high-resolution display.

Electrical Instabilities and 1/f Noise in Organic Pentacene Thin Film Transistors

2000 ◽  
Vol 660 ◽  
Author(s):  
P. V. Necliudov ◽  
M. Shur ◽  
D. J. Gundlach ◽  
T. N. Jackson
Keyword(s):  
Thin Film ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Electrical Characteristics ◽  
Threshold Voltage Shift ◽  
Current Voltage ◽  
Noise Measurements ◽  
Current Voltage Characteristics ◽  
Amorphous Si ◽  
Bias Temperature Stress

ABSTRACTWe report on the influence of Bias-Temperature Stress (BTS) on the pentacene Thin Film Transistors (TFTs) electrical characteristics and on their 1/f noise level. The gate BTS primarily affects the TFT threshold voltage, leaving both mobility and sub-threshold slope values almost unchanged. The degree of the threshold voltage shift induced by the positive or negative BTS depends on the TFT design and the BTS parameters. The current-voltage characteristics time dependence of the organic TFTs, subjected to the BTS, resembles that for amorphous-Si TFTs. The results of the 1/f noise measurements in the organic TFTs allowed us to conclude that the gate BTS primarily affects the TFT contact regions, resulting in the increase of both the contact noise and the contact resistance.

Threshold Voltage Shifts in Amorphous Silicon Thin Film Transistors under Bias Stress

1990 ◽  
Vol 192 ◽  
Author(s):  
Tetsu Ogawa ◽  
Sadayoshi Hotta ◽  
Horoyoshi Takezawa
Keyword(s):  
Thin Film ◽  
Temperature Dependence ◽  
Amorphous Silicon ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Charge Trapping ◽  
The Other ◽  
Time Dependent ◽  
Silicon Thin Film ◽  
Bias Stress

ABSTRACTThrough the time and temperature dependence measurements on threshold voltage shifts (Δ VT) in amorphous silicon thin film transistors, it has been found that two separate instability mechanisms exist; within short stress time ranges Δ Vτ increases as log t and this behavior corresponds to charge trapping in SiN. On the other hand, in long stress time ranges Δ VT increases as t t/4 and can be explained by time-dependent creation of trap in a-Si.

Effect of dielectric/organic interface properties on the performance of the organic thin film transistors

2013 ◽  
Vol 1501 ◽  
Author(s):  
Ronak Rahimi ◽  
D. Korakakis
Keyword(s):  
Molecular Structure ◽  
Thin Film ◽  
Thin Film Transistors ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Organic Thin Film Transistors ◽  
Device Performance ◽  
Electrical Characteristics ◽  
Organic Thin Film ◽  
Organic Layers

ABSTRACTIn order to manufacture organic electronic devices with high performance, more detailed studies of the structure and the morphology of the organic materials as well as the underlying physical charge transport mechanisms are warranted. For instance, high efficiency organic thin film transistors (OTFTs) require materials with high charge carrier mobility [1, 2]. The parameters that determine the charge carrier mobility of the device include the structure of the first organic layer at the organic-dielectric interface as well as the morphology and the structural order of the other organic layers. Therefore, fundamental questions about structural properties of organic materials should be answered in order to optimize device performance [2-4].In this work, several bilayer structures of LiF/PTCDI-C8 and LiF/pentacene were prepared and their morphology and molecular structure were characterized using X-ray reflectivity (XRR) technique. In order to study the effects of the films’ structures and dielectric/organic interfacial properties on the device performance, OTFTs based on these bilayers were fabricated and characterized. It has been observed that PTCDI-C8 thin films have higher molecular packing in the LiF/PTCDI-C8 bilayer structure, which results in superior electrical characteristics for OTFTs based on this organic material. Devices with LiF/PTCDI-C8 bilayer exhibit about one order of magnitude higher output current (Ids) at a constant drain-source voltage (Vds) compared to the devices with LiF/pentacene bilayer. The observed differences in the electrical characteristics of these devices can be attributed to the effects of the dielectric/organic interface and the molecular structure of the organic layers.

Effect of Oxygen Partial Pressure on Electrical Characteristics of Amorphous Zinc-Tin-Oxide Thin-Film Transistors

2014 ◽  
Vol 590 ◽  
pp. 229-233
Author(s):  
Sheng Po Chang
Keyword(s):  
Thin Film ◽  
Tin Oxide ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Oxide Thin Film ◽  
Electrical Characteristics ◽  
Subthreshold Slope ◽  
Partial Pressures ◽  
Zinc Tin Oxide ◽  
Effect Of Oxygen

We fabricated and studied the electrical characteristics of thin-film transistors with an amorphous zinc-tin–oxide (a-ZTO) channel, which was deposited by radio frequency magnetron co-sputtering under different oxygen partial pressures. The effect of varying the oxygen concentration on the electrical properties and device performance of the a-ZTO TFTs was investigated. A positive shift observed in the threshold voltage with increasing oxygen suggests that the number of oxygen vacancies in the a-ZTO film decreased. With an oxygen flow rate of 4 %, a threshold voltage of 2.25 V, an on-off current ratio of 2.1 × 103, and a subthreshold slope of 0.8 V·dec−1were obtained.

60Co Gamma–Ray Irradiation Effects on Pentacene-Based Organic Thin-Film Transistors

2011 ◽  
Vol 687 ◽  
pp. 576-579 ◽  
Author(s):  
Li Cai ◽  
Toshio Hirao ◽  
Hiroaki Yano ◽  
Zong Fan Duan ◽  
Hideharu Takayanagi ◽  
...  
Keyword(s):  
Thin Film ◽  
Total Dose ◽  
Threshold Voltage ◽  
Thin Film Transistors ◽  
Radiation Effects ◽  
Rebound Effect ◽  
Charge Trapping ◽  
Organic Thin Film Transistors ◽  
Gate Insulator ◽  
Organic Thin Film

Electrical characterization of 60Co γ-ray radiation effects on pentacene-based organic thin-film-transistors having two kinds of gate insulator have been carried out. For transistors with SiO2 gate insulator, the threshold voltage shifts are consistent with positive charge trapping in the oxide and a “rebound” effect is observed. This “rebound” effect is attributed to the negatively charged interface traps generated during irradiation. For polyimide gate insulator, the threshold voltage continually decreases with an increasing total-dose. At total-dose of 1200 Gy (Si), for the SiO2 gate insulator, the field-effect mobility decreased by almost 80%, and for polyimide gate insulator, it decreased by 40%.

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.

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