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2. 97‐2: Late‐News Paper: Development of High‐Mobility Indium‐rich IGZO TFT Device for IT OLED Display.

Author

Cho, Hyun-Min, Ryoo, Chang-Il, Yun, Pil-Sang, Bae, Jong-Uk, and Park, Yoo-Seok

Subjects
CARRIER density, THRESHOLD voltage, PRODUCT attributes, INDIUM gallium zinc oxide, INDIUM
Abstract

High‐end MNT, NBPC OLED displays require high resolution and high‐speed driving characteristics. In addition, as an OLED backplane, a high mobility and excellent reliability characteristics of TFT are required. We have developed high mobility devices by using Indium (In‐) rich a‐IGZO. In the In‐rich a‐IGZO TFT process, a relatively large amount of oxygen is used compared to conventional a‐IGZO (In:Ga:Zn 1:1:1) in order to control the variation of the threshold voltage (VTH) caused by high carrier concentration. However, the increase in excess oxygen leads to a decrease in reliability, making it even more difficult to satisfy both VTH dispersion and reliability at the same time. We have developed a‐IGZO TFTs that have excellent reliability characteristics while satisfying VTH dispersion and mobility by controlling the vertical and lateral distribution of oxygen and hydrogen. Furthermore, it has been confirmed that the 27‐inch QHD OLED monitor, which incorporates high‐mobility a‐IGZO TFTs, satisfies the product reliability characteristics. [ABSTRACT FROM AUTHOR]

Published
2024
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3. 97‐2: Late‐News Paper:Development of High‐Mobility Indium‐rich IGZO TFT Device for IT OLED Display

Author

Cho, Hyun-Min, Ryoo, Chang-Il, Yun, Pil-Sang, Bae, Jong-Uk, and Park, Yoo-Seok

Abstract

High‐end MNT, NBPC OLED displays require high resolution and high‐speed driving characteristics. In addition, as an OLED backplane, a high mobility and excellent reliability characteristics of TFT are required. We have developed high mobility devices by using Indium (In‐) rich a‐IGZO. In the In‐rich a‐IGZO TFT process, a relatively large amount of oxygen is used compared to conventional a‐IGZO (In:Ga:Zn 1:1:1) in order to control the variation of the threshold voltage (VTH) caused by high carrier concentration. However, the increase in excess oxygen leads to a decrease in reliability, making it even more difficult to satisfy both VTH dispersion and reliability at the same time. We have developed a‐IGZO TFTs that have excellent reliability characteristics while satisfying VTH dispersion and mobility by controlling the vertical and lateral distribution of oxygen and hydrogen. Furthermore, it has been confirmed that the 27‐inch QHD OLED monitor, which incorporates high‐mobility a‐IGZO TFTs, satisfies the product reliability characteristics.

Published
2024
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6. Thermal Process and Dopant Diffusion Model of a-InGaZnO TFTs for VT Prediction Using Lateral Carrier Density Profiling Technique

Author

Myoung, Seung Joo, Ryoo, Chang Il, Kim, Changwook, Choi, Sung-Jin, Kim, Dong Myong, Bae, Jong-Ho, and Kim, Dae Hwan

Abstract

To establish a thermal process and corresponding dopant diffusion model to predict the properties of a-InGaZnO (a-IGZO) TFTs, the dopant distribution along the a-IGZO channel after thermal process is analyzed and modeled in detail. Considering that the thermal process induces diffusion of the dopants and changes carrier density ( ${n}{(}{y}{)}{)}$ in the a-IGZO film along the channel length direction ( ${y}{)}$ , the lateral diffusion coefficient ( ${D}_{y}{)}$ according to the post-annealing temperature ( ${T}_{\text {post}}{)}$ is extracted. Consistency of the measured and simulated ${V}_{\text {T}}$ of a-IGZO TFTs is confirmed for ${T}_{\text {post}}$ from 353 K to 573 K, indicating that ${n}{(}{y}{)}$ and ${V}_{\text {T}}$ changes during annealing are predictable. The results can become a cornerstone of a-IGZO TFT process simulation and suggest the possibility of precise modulation of ${V}_{\text {T}}$ of a-IGZO TFTs by controlling the annealing conditions.

Published
2023
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8. 9.3: Control of Threshold Voltage in Back Channel Etch Type Amorphous Indium Gallium Zinc Oxide Thin Film Transistors

Author

Lee, Seung Min, primary, Ryoo, Chang Il, additional, Park, Jae Wook, additional, Han, Joonsoo, additional, Kim, Dae-Won, additional, Kim, Yong-Yub, additional, Kang, Im-Kuk, additional, Seo, Kyung-Han, additional, Koh, Young Ju, additional, Han, Dong-Min, additional, Choi, Yong-Ho, additional, Seo, Hyun-Sik, additional, Kim, Bong Chul, additional, Cha, Soo Youle, additional, Bae, Jong-Uk, additional, Kim, Chang Dong, additional, Jun, Myungchul, additional, and Hwang, Yong Kee, additional

Published
2011
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10. P‐3: Scaling of a‐Si TFT Gate Drivers

Author

Jang, Yong Ho, primary, Kim, Hae Yeol, additional, Kim, Binn, additional, Choi, Seung Chan, additional, Cho, Hyung Nyuck, additional, Ryoo, Chang Il, additional, Choi, Wooseok, additional, Yoon, Soo Young, additional, Park, Kwon‐shik, additional, Moon, Taewoong, additional, Cho, Nam Wook, additional, and Kim, Chang‐Dong, additional

Published
2009
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11. Amorphous-silicon gate-driver circuits of shared-node dual pull-down structure with overlapped output signals

Author

Cho, Hyung Nyuck, primary, Kim, Hae Yeol, additional, Ryoo, Chang il, additional, Choi, Seung Chan, additional, Kim, Binn, additional, Jang, Yong Ho, additional, Yoon, Soo Young, additional, Chun, Min Doo, additional, Park, Kwon-shik, additional, Moon, Taewoong, additional, Cho, Nam Wook, additional, Jo, Sung Hak, additional, Kim, Sung Ki, additional, Kim, Chang-Dong, additional, and Kang, In Byeong, additional

Published
2008
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12. Amorphous-silicon gate-driver circuits of shared-node dual pull-down structure with overlapped output signals

Author

Binn Kim, Nam Wook Cho, Choi Seung Chan, Taewoong Moon, Kwon-Shik Park, Chun Min Doo, Hae Yeol Kim, Chang-Dong Kim, Ryoo Chang Il, Soo Young Yoon, In Byeong Kang, Sung Ki Kim, Yong Ho Jang, Cho Hyung Nyuck, and Sung Hak Jo

Subjects
Amorphous silicon, Materials science, business.industry, Controller (computing), Electrical engineering, Hardware_PERFORMANCEANDRELIABILITY, Atmospheric temperature range, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, chemistry, Hardware_INTEGRATEDCIRCUITS, Gate driver, RGB color model, Node (circuits), Electrical and Electronic Engineering, business, Electronic circuit, Shift register
Abstract

— A novel gate-driver circuit using amorphous-silicon (a-Si) TFTs has been developed. The circuit has a shared-node dual pull-down AC (SDAC) structure with a common-node controller for two neighboring stages, resulting in a reduced number of TFTs. The overlapped clock signals widen the temperature range for stable operation due to the extended charging time of the inner nodes of the circuit. The accelerated lifetime was found to be over 1000 hours at 60°C with good bias-temperature-stress (BTS) characteristics. Accordingly, the a-Si gate-driver circuit was successfully integrated into a 14.1-in. XGA (1024 × RGB × 768) TFT-LCD panel having a single bank form.

Published
2008

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