• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.609-613
• /
• 2005

Advanced mobile communication devices require a bright, high information content display in a small, light-weight, low power consumption package. In this paper we will outline our progress towards developing such a low power consumption active-matrix flexible OLED ($FOLED^{TM}$) display. Our work in this area is focused on three critical enabling technologies. The first is the development of a high efficiency long-lived phosphorescent OLED ($PHOLED{TM}$) device technology, which has now proven itself to be capable of meeting the low power consumption performance requirements for mobile display applications. Secondly, is the development of flexible active matrix backplanes, and for this our team are employing poly-Si TFTs formed on metal foil substrates as this approach represents an attractive alternative to fabricating poly-Si TFTs on plastic for the realization of first generation flexible active matrix OLED displays. Unlike most plastics, metal foil substrates can withstand a large thermal load and do not require a moisture and oxygen permeation barrier. Thirdly, the key to reliable operation is to ensure that the organic materials are fully encapsulated in a package designed for repetitive flexing. We also present progress in operational lifetime of encapsulated T-PHOLED pixels on planarized metal foil and discuss PHOLED encapsulation strategy.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.301.2-301.2
• /
• 2016

Metal-oxide thin-film transistors (TFTs) have gained a considerable interest in transparent electronics owing to their high optical transparency and outstanding electrical performance even in an amorphous state. Also, these metal-oxide materials can be solution-processed at a low temperature by using deep ultraviolet (DUV) induced photochemical activation allowing facile integration on flexible substrates [1]. In addition, high-dielectric constant (k) inorganic gate dielectrics are also of a great interest as a key element to lower the operating voltage and as well as the formation of coherent interface with the oxide semiconductors, which may lead to a considerable improvement in the TFT performance. In this study, we investigated the electrical properties of solution-processed high-k strontium-doped AlOx (Sr-AlOx) gate dielectrics. Using the Sr-AlOx as a gate dielectric, indium-gallium-zinc oxide (IGZO) TFTs were fabricated and their electrical properties are analyzed. We demonstrate IGZO TFTs with a 10-nm-thick Sr-AlOx gate dielectric which can be operated at a low voltage (~5 V).

• Electronic Materials Letters
• /
• v.14 no.6
• /
• pp.749-754
• /
• 2018

Previous studies have reported on the mechanical robustness and chemical stability of flexible amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) on plastic substrates both in flat and curved states. In this study, we investigate how the polyimide (PI) substrate affects hydrogen concentration in the a-IGZO layer, which subsequently influences the device performance and stability under bias-temperature-stress. Hydrogen increases the carrier concentration in the active layer, but it also electrically deactivates intrinsic defects depending on its concentration. The influence of hydrogen varies between the TFTs fabricated on a glass substrate to those on a PI substrate. Hydrogen concentration is 5% lower in devices on a PI substrate after annealing, which increases the hysteresis characteristics from 0.22 to 0.55 V and also the threshold voltage shift under positive bias temperature stress by 2 ${\times}$ compared to the devices on a glass substrate. Hence, the analysis and control of hydrogen flux is crucial to maintaining good device performance and stability of a-IGZO TFTs.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.1546-1549
• /
• 2006

We have developed $EPLaR^{TM}$, a new way of making flexible electrophoretic displays. The TFTs have the same good performance, reliability and mature manufacturing processes as TFTs used in LCD monitors and LCD-TVs. We are working with partners to show that plastic displays can be made in existing TFT-LCD factories alongside glass LCDS. In this talk we describe the EPLaR process and show results for TFT arrays on plastic made in a factory by standard ${\alpha}$-Si TFT processing.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.322-325
• /
• 2009

Amorphous oxide semiconductors (AOSs) are expected as new channel materials in TFTs for largearea and/or flexible FPDs, and several prototype displays have been demonstrated in these five years since the first report of AOS TFT. In this paper, we review fundamental materials science of AOSs that have been clarified to date in connection with operation characteristics of AOS TFTs.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.1297-1300
• /
• 2008

Electrical stress degradation of low temperature, amorphous silicon thin film transistors is reviewed, and the implications for various types of flexible circuitry including active matrix backplanes, integrated drivers and general purpose digital circuitry are examined. A circuit modeling tool that enables the prediction of complex circuit degradation is presented.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.297-300
• /
• 2005

The characteristics of polycrystalline silicon thin-film transistors (poly-Si TFTs) fabricated using sputter deposited amorphous silicon (a-Si) precursor films are investigated. The a-Si films were deposited on flexible polymer substrates using argon-helium mixture gases to minimize the argon incorporation into the film. The precursor films were then laser annealed by using a XeCl excimer laser and a four-mask-processed poly-Si TFT was fabricated with fully self-aligned top gate structure. The fabricated pMOS TFT showed field-effect mobility of $32.4cm^2/V{\cdot}s$ and on/off ratio of $10^6$.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.64-67
• /
• 2005

We fabricated an array consisting of organic TFTs(OTFT) and organic LEDs (OLED) in order to demonstrate the possible application of OTFTs to flexible active matrix OLED (AMOLED). The panel was composed of $64{\times}64$ pixels on 4 inch size polyethylene-terephehalate (PET) substrate in which each pixel had one OTFT integrated with one green OLED. The panel successfully displayed some letters and pictures by emitting green light with a luminance of $1.5\;cd/m^2$ at 6 V, which was controlled by the gate voltage of OTFT.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.258-261
• /
• 2009

In this work we present a process to fabricate lowtemperature polysilicon (LTPS) TFTs on polyimide (PI) layers, spin-coated on Si-wafer used as rigid carrier. This process has been then used to fabricate elementary circuits as well as circuits for sensor applications.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.749-751
• /
• 2007

A buffer layer consisting of $SiO_x/Ta/Ti$ has been developed in order to overcome the adhesion and stress problems between poly-Si film and mica. Polycrystalline silicon thin film transistor was successfully fabricated on the mica and transferred to a flexible plastic substrate.