The flexible display is emerging as it provides another degree of freedom for system design. Papers related to TFTs and their circuits either built directly on a plastic substrate or transferred from a glass substrate are solicited.

TFTs ON FLEXIBLE SUBSTRATES

Thursday, May 26

9:00–10:20am

Room 133

Several sensor and circuit solutions for organic flexible electronic devices will be described. Organic field-effect transistors (OFETs) enable light weight, low cost, high flexibility, and large area for smart sensors. However, the design of organic flexible circuits pose great challenges because of the intrinsic properties of organic materials requiring new circuit techniques to overcome these challenges for correct and robust operation.

A. K. M. Mahfuzul Islam,
T. Yokota, M. Takamiya,
T. Someya,
T. Sakurai
University of Tokyo, Tokyo, Japan and JST/ERATO, Tokyo, Japan

H. Fuketa
University of Tokyo, Tokyo, Japan and National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan

K. Ishida
University of Tokyo, Tokyo, Japan and Dresden University of Technology, Dresden, Germany

T. Sekitani
University of Tokyo, Tokyo, Japan and JST/ERATO, Tokyo, Japan and Osaka University, Osaka, Japan

OLED display technologies are bringing a new viewing experience into a wide range of applications. For large-area and high-resolution flexible OLED displays, high-performance and reliable TFT backplanes on plastic substrates are essential. Recent work on the development of oxide and organic-based TFTs on flexible substrates, in addition to solution-based materials, will be reviewed.

Y. Fujisaki,
M. Nakata,
Y. Nakajima,
H. Tsuji,
M. Miyakawa,
G. Motomura,
H. Fukagawa,
T. Shimizu,
T. Tsuzuki,
T. Takei,
T. Yamamoto
NHK Science & Technology Research Laboratories, Tokyo,Japan

Sputter-deposited a-IGZO films usually require an annealing process over 300°C for activation. This annealing process limits the use of various flexible substrates. To overcome this drawback, low-temperature activated a-IGZO TFTs by simultaneous UV and thermal (SUT), electrical-assisted thermal (EAT),and high-pressure-annealing (HPA) methods are proposed.

H. J. Kim
Yonsei University, Seoul, South Korea

A flexible AMOLED display driven by oxide TFTs with a triple-stacked active layer on a polyimide substrate is reported. The fabricated TFT parameters include a mobility 38.8 cm2/V-sec, subthreshold swing of 0.15 V/dec, and an Ion/Ioff ratio of 109. An ALD Al2O3 encapsulation achieves an estimated WVTR of 5.43 x 10-5 g/m2/day at 40°C/100%.

H. Xu,
M. Li,
L. Wang,
M. Xu
South China University of Technology, Guangzhou, P. R. China and Guangzhou New Vision Opto-Electronic Technology Co., Ltd., Guangzhou, P. R. China

H. Ning,
J. Peng
South China University of Technology, Guangzhou, P. R. China

FLEXIBLE/PRINTED TFTs

Thursday, May 26

3:10pm –4:30pm

Room 130

The development of organic semiconductors and passive material formulations optimized for photolithographic integration using existing photoresist materials and technology have been demonstrated. These materials can be coated and patterned to produce organic TFTs suitable for integration into mass-production processes with a charge-carrier mobility of greater than 2 cm2/V-sec.

S. Bain,
P. Miskiewicz,
I. Afonina,
T. Backlund
Merck Chemicals, Ltd. (a subsidiary of Merck KGaA,Darmstadt, Germany), Southampton, UK

Targeting flexible-display backplanes and circuitry, high-performance materials for organic field-effect transistors are being developed. Recent developments focusing on directly photo-patternable semiconductors and dielectrics, as well as new semiconductors for solution-processed transistors with mobilities of up to 4 cm2/V-sec will be discussed.

D. Kaelblein,
T. Musiol,
D. Bahl,
F. G. Brunetti,
J. Brill
BASF SE, Ludwigshafen, Germany

R. Pretot,
P. Hayoz
BASF Schweiz AG, Basel, Switzerland

Z. Mi
BASF Company, Ltd., Seoul, South Korea

O. Ossó,
K. Exner
BASF New Business GmbH, Ludwigshafen, Germany

A 4-in. flexible AMOLED display with a high-yield integrated gate driver based on the bulk-accumulation (BA) oxide TFTs has been demonstrated. Highperformance BA-oxide TFTs with a 320-stage shift resistor was applied to flexible mobile AMOLED displays.

J. G. Um,
D. Geng,
M. Mativenga,
J. Jang
Kyung Hee University, Seoul, South Korea

Compared to conventional amorphous-silicon (a-Si) TFTs, amorphous metaloxide TFTs have superior device performance such as higher mobility, better sub-threshold swing, and lower off-state current. The development of printedmetal-oxide TFTs will be discussed, including the ink formulations, the types and characteristics of the applied printers, and TFT characteristics.

C-H. Chang,
S-Y. Han,
J. Y. Gorecki,
C-H. Chang
Oregon State University, Corvallis, OR, USA

L-Y. Lin,
C-C. Cheng
AU Optronics Corp., Hsinchu, Taiwan, ROC