scholarly journals Effect of the Degree of the Gate‐Dielectric Surface Roughness on the Performance of Bottom‐Gate Organic Thin‐Film Transistors

2020 ◽  
Vol 7 (10) ◽  
pp. 1902145 ◽  
Author(s):  
Michael Geiger ◽  
Rachana Acharya ◽  
Eric Reutter ◽  
Thomas Ferschke ◽  
Ute Zschieschang ◽  
...  
2007 ◽  
Vol 124-126 ◽  
pp. 383-386
Author(s):  
Jae Bon Koo ◽  
Jung Wook Lim ◽  
Chan Hoe Ku ◽  
Sang Chul Lim ◽  
Jung Hun Lee ◽  
...  

We report on the fabrication of dual-gate pentacene organic thin-film transistors (OTFTs) using a plasma-enhanced atomic layer deposited (PEALD) 150 nm thick Al2O3 as a bottom gate dielectric and a 300 nm thick parylene or a PEALD 200 nm thick Al2O3 as both a top gate dielectric and a passivation layer. The threshold voltage (Vth) of OTFT with a 300 nm thick parylene as a top gate dielectric is changed from 4.7 V to 1.3 V and that with a PEALD 200 nm thick Al2O3 as a top gate dielectric is changed from 1.95 V to -9.8 V when the voltage bias of top gate electrode is changed from -10 V to 10 V. The change of Vth of OTFT with the dual-gate structure has been successfully understood by an analysis of electrostatic potential.


1999 ◽  
Vol 558 ◽  
Author(s):  
C.D. Sheraw ◽  
D.J. Gundlach ◽  
T.N. Jackson

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.


2005 ◽  
Vol 15 (3) ◽  
pp. 202-208
Author(s):  
Sang Chul Lim ◽  
Seong Hyun Kim ◽  
Jung Hun Lee ◽  
Chan Hoe Ku ◽  
Dojin Kim ◽  
...  

2021 ◽  
Vol 16 (2) ◽  
pp. 1-11
Author(s):  
José Enrique Eirez Izquierdo ◽  
José Diogo da Silva Oliveira ◽  
Vinicius Augusto Machado Nogueira ◽  
Dennis Cabrera García ◽  
Marco Roberto Cavallari ◽  
...  

This work is focused on the bias stress (BS) effects in Organic Thin-Film Transistors (OTFTs) from poly(2,5-bis(3-alkylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT-C14) on both highly-doped Si and glass substrates. While the former had a thermally-grown SiO2 dielectric, the latter demanded an alternative dielectric that should be capable to withstand bottom contact lithography, as well as semiconducting thin-film deposition. In addition, it should represent one more step towards flexible electronics. In order to do that, poly(4-vinylphenol) (PVP) was blended to poly(melamine-co-formaldehyde) methylated (PMF). OTFTs on glass with a cross-linked polymer dielectric had a charge carrier mobility (μ) of 4.0x10-4 cm2/Vs, threshold voltage (VT) of 18 V, current modulation (ION/OFF) higher than 1x102, and subthreshold slope (SS) of -7.7 V/dec. A negative BS shifted VT towards negative values and produced an increase in ION/OFF. A positive BS, on the other hand, produced the opposite effect only for OTFTs on Si. This is believed to be due to a higher trapping at the PVP:PMF interface with PBTTT-C14. Modeling the device current along time by a stretched exponential provided shorter time constants of ca. 105 s and higher exponents of 0.7–0.9 for devices on glass. Due to the presence of increased BS effects, the application of organic TFTs based on PVP:PMF as flexible sensors will require compensating circuits, lower voltages or less measurements in time. Alternatively, BS effects could be reduced by a dielectric surface treatment.


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