Chyi-Ming Leu

High-Performance Flexible a-IGZO TFTs Adopting Stacked Electrodes and Transparent Polyimide-Based Nanocomposite Substrates

We demonstrated flexible amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) on fully transparent and high-temperature polyimide-based nanocomposite substrates. The flexible nanocomposite substrates were coated on the carrier glass substrates and were debonded after the TFT microfabrication. The adoption of the Ti/IZO stacked electrodes as source/drain/ gain electrodes significantly improved the etching compatibility with other material layers, enabling successful implementation of flexible a-IGZO TFTs onto the transparent nanocomposite substrates by conventional lithographic and etching processes. The flexible a-IGZO TFTs exhibited decent mobility and mechanical bending capability. Field-effect mobility of up to 15.9 cm2/V · s, a subthreshold swing of 0.4 V/dec, a threshold voltage of 0.8 V, and an on/off ratio of >; 108 were extracted from the TFT characteristics. The devices could be bent down to a radius of curvature of 3 mm and yet remained normally functional. Such successful demonstration of flexible oxide TFTs on transparent flexible substrates using fully lithographic and etching processes that are compatible with existing TFT fabrication technologies shall broaden their uses in flexible displays and electronics.

Effects of Mechanical Strains on the Characteristics of Top-Gate Staggered a-IGZO Thin-Film Transistors Fabricated on Polyimide-Based Nanocomposite Substrates

In this paper, we had successfully implemented flexible top-gate staggered amorphous In-Ga-Zn-O (a-IGZO) thin- film transistors (TFTs) on colorless and transparent polyimide (PI)-based nanocomposite substrates using fully lithographic and etching processes that are compatible with existing TFT mass fabrication technologies. The use of the selectively coated release layer between the nanocomposite PI film and the glass carrier ensured smooth debonding of the plastic substrate after TFT fabrication. The TFTs showed decent performances (with mobility >; 10 cm2/V · s) either as fabricated or as debonded from the carrier glass. By bending the devices to different radii of curvature (from a flat state to an outward bending radius of 5 mm), influences of mechanical strains on the characteristics of flexible a-IGZO TFTs were also investigated. In general, the mobility of the flexible a-IGZO TFT increased with the tensile strain, whereas the threshold voltage decreased with the tensile strain. The variation of the mobility in a-IGZO TFTs versus the strain appeared smaller than those observed for amorphous silicon TFTs.

High-performance organic-inorganic hybrid plastic substrate for flexible displays and electronics

— An inorganic-dominated silica/polyimide (PI) hybrid film has been successfully developed for the fabrication of flexible AMOLEDs. The existence of networks between silica particles in the PI matrix have been confirmed by 3-D tomography, respectively. The inorganic—organic hybrid film was achieved by roll-type processing with a variety of attractive properties, such as low coefficient of thermal expansion (CTE, 20 ppm/°C), high transmittance (within the wavelength range of 400–700 nm), excellent flexibility, and high Youngs modulus. Additionally, a flexible color-filter, an AMEPD, and a flexible touch film were fabricated on hybrid film.

Novel near-infrared and multi-colored electrochromic polybenzoxazines with electroactive triarylamine moieties

Two triarylamine-containing flexible polybenzoxazine films with Tg up to 312 °C were prepared by the thermally induced curing reaction of the corresponding polybenzoxazine precursors, which were synthesized by the reaction of paraformaldehyde with bisphenol A and 4,4′-diamino-4′′-methoxytriphenylamine (1) or N,N′-bis(4-aminophenyl)-N,N′-di(4-methoxyphenyl)-1,4-phenylenediamine (2). By introduction of triarylamine units into the polybenzoxazine precursors, the resulting solution-processable polybenzoxazine precursor films not only exhibited interesting multi-colored electrochromic behavior with a high contrast ratio both in the visible range and near infrared region (NIR) but also could effectively increase the oxidation stages when compared with their corresponding polyamides.

61.2: Invited Paper: High Performance Organic-Inorganic Hybrid Plastic Substrate for Flexible Display and Electronics

An inorganic dominated silica/polyimide (PI) hybrid film has been successfully developed for the fabrication of flexible AM-OLED. The inorganic-organic hybrid film was achieved in roll type with a variety of attractive properties such as low coefficient of thermal expansion (CTE, 33 ppm/°C), high transmittance (within the wavelength range of 400 to 700 nm), excellent flexibility and high Yangs modulus.

P-11: Amorphous In2O3-Ga2O3-ZnO Thin Film Transistors and Integrated Circuits on Flexible and Colorless Polyimide Substrates

A process was developed for fine fabrication of amorphous IGZO TFTs and integrated circuits on flexible and colorless polyimide substrates. TFTs with field-effect mobilities of ∼10 cm2/Vs and ring oscillators with propagation delay of 0.35 μs per stage were achieved on the polyimide substrates.

58.1: A 4.1-Inch Flexible QVGA AMOLED Using a Microcrystalline-Si:H TFT on a Polyimide Substrate

A 4.1-inch flexible QVGA AMOLED display with microcrystalline silicon (μc-Si:H) TFTs backplane on colorless polyamide (PI) substrate is demonstrated. The PI substrate has the features of high Tg (∼350°C) and high light transmittance (∼90%). The bottom-gate μc-Si:H TFTs backplane is fabricated at 200°C by a conventional (13.56 MHz) plasma-enhanced chemical vapor deposition (PECVD) system. The flexible μc-Si:H TFTs backplane shows better electrical stability, flexibility, and uniformity.

22.3: Flexible Top‐gate Amorphous InGaZnO TFTs Array for AMOLED Applications

Flexible top-gate amorphous InGaZnO TFTs array on a colorless polyimide substrate for AMOLED applications was successfully fabricated at 200 °C for the first time. The light transmittance of polyimide substrate is 90%. The maximum field-effect mobility is 10.6 cm2/V-s, subthreshold swing is 0.3 V/decade, and the on/off current ratio is 108.

P‐37: Room Temperature Top‐Gate Self‐Aligned Amorphous InGaZnO TFTs Fabricated on Colorless Polyimide Substrate

Room temperature top-gate self-aligned amorphous InGaZnO TFTs were successfully fabricated on colorless polyimide plastic substrates for the first time. All these thin films were deposited by sputtering system at room temperature. The maximum field-effect mobility is 48.5 cm2/V-s, the subthreshold swing is 0.1 V/decade, and the threshold voltage is −1V.

43.3: A Novel Flexible AMOLED with Touch Based on Flexible Universal Plane for Display Technology

A flexible thin film transistor (TFT) backplane, OLED, and the flexible projective capacitive touch sensing film were successfully developed and integrated with colorless and transparent Polyimide (PI) substrate for the first flexible touch AMOLED display based on the flexible universal plane for display (FlexUPD) technology. This unique substrate handling technology is not only compatible with the current TFT manufacturing facilities but also allows us to use the same design rule of TFT backplane as that on the glass.