60‐4: Mechanically Robust High‐Performance Flexible Oxide TFTs with Imbedded Buried CNT Electrode for Bendable Displays

Abstract

We demonstrate highly robust flexible a-IGZO thin-film transistors (TFTs) with imbedded carbon nano-tube (CNT) buried electrode (BE) in between polyimide (PI) substrate. The excellent mechanical durability of flexible TFTs on thin wrinkle-free and the self-standing PI substrate with imbedded CNT BE has been demonstrated. The strain on the TFT can be reduced by the imbedded CNT electrode which is calculated from the 3D-TCAD simulation. KeywordsAmorphous-indium-gallium-zinc-oxide (a-IGZO), thin-film transistor (TFT), buried electrode (BE), Technology computeraided design (TCAD).

Fatigue Effect of Stretchable a-InGaZnO TFT on PI/PDMS Substrate under Repetitive Uni/Biaxial Elongation Stress

“…The stability test was conducted under a gate bias of ±20 V for 3600 s at room temperature. Contact resistance analysis was conducted using the TLM method. , The density of states (DOS) model of ATLAS TCAD was used to simulate the change of the electrical characteristics after elongation stress. , The mechanical-stress-dependent chemical binding states of the IGZO thin films were evaluated by X-ray photoelectron spectroscopy (XPS, theta-probe, installed at the Hanyang Center for Research Facilities (Seoul)). Static stress evaluation is performed by measuring TFTs while stretching the biaxis jig as shown in Figure (c).…”

Research Progress on Flexible Oxide-Based Thin Film Transistors

“…Despite all of the differences in bending behaviors, TFTs suffer no more than the tensile or compressive strain from along with the channel length or the channel width as the mechanical process is applied. Figure 11 shows the four common types of bending test platforms: (A) the substrate between two moving metal splints can be bent to various radius [173], (B) the substrate is wrapped around a rigid cylindrical rods, which makes it easy to contact the electrodes with probes [158], (C) custom-built bending testers for flexible TFTs and displays [162], which includes a programmed counter, a dc motor and a jig. With this kind of testers, the number of bends on devices or displays can be counted conveniently.…”

“…Furthermore, when the radius of curvature and the mechanical stress increase beyond tolerance, cracks in the substrate emerge and TFTs will fail. Hence, it is necessary for researchers to comprehend the impact of mechanical stress on flexible device performance [173][174][175][176][177][178][179][180][181][182][183]. In fact, with the widely extending use of flexible applications, bending behaviors of the TFTs will become more and more complex.…”

“…2019, 9, x FOR PEER REVIEW 14 of 27 Figure 11. Bending test platforms (a) Substrate between two moving metal splints [173]. (b) Substrate wrapped around the rigid cylindrical rods [158].…”

Recent review on improving mechanical durability for flexible oxide thin film transistors

“…Thus, much research has been done to find suitable flexible substrates [63-66]. Among them, PI and polyethylene naphthalate (PEN) are the most widely used for flexible TFT substrates [55, [67][68][69][70][71][72][73][74][75][76][77]. PI has a high glass transition temperature (>350 °C) and a low rate of thermal expansion (5-10 ppm °C−1 ) compared to other plastic substrates.…”