Anomalous Kink Effect Induced by Bottom-Shield-Metal in LTPS TFTs on Plastic Substrates

Kim, Ki Woo; Kang, Jongseuk; Ku, Hoewoo; Lee, Kyung-Ho; Kim, Hyun Jae

doi:10.1109/led.2018.2867942

Cited by 10 publications

(6 citation statements)

References 21 publications

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“…To prevent moisture penetration through the PI substrate, SiO 2 and SiN x layers were deposited in a multistack using plasma-enhanced chemical vapor deposition (PECVD). Mo was patterned by photolithography as the bottom gate of an a-IGZO TFT to exclude the influence of the charge polarity of the PI substrate. , A 300-nm-thick SiO 2 layer was deposited by PECVD as a buffer layer. Next, the a-IGZO active layer (In:Ga:Zn = 1:1:1 atomic ratio) was deposited as a 30-nm-thick layer using direct current (DC) sputtering and then patterned.…”

Section: Methodsmentioning

confidence: 99%

Performance Improvement of Self-Aligned Coplanar Amorphous Indium–Gallium–Zinc Oxide Thin-Film Transistors by Boron Implantation

Kang

Lee

Kwak

et al. 2022

ACS Appl. Electron. Mater.

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The electrical properties and device stability of a self-aligned (SA) coplanar amorphous indium−gallium−zinc oxide (a-IGZO) thin-film transistor (TFT) were investigated by implanting boron (B) into the source/drain (SD) n + region. To evaluate the effect according to the depth profile of B in the a-IGZO film, various implantation energies were applied. The electrical properties were optimized when the projection range of B was in the central vertical region of the a-IGZO film. B implantation decreased the resistivity of the a-IGZO film from 3.1 × 10 2 to 2.1 × 10 −3 Ω•cm compared to an untreated a-IGZO film, while the field-effect mobility (μ fe ) improved from 2.96 to 17.22 cm 2 /(V•s). Moreover, the fabricated SA coplanar a-IGZO TFTs with a B-doped n + region exhibited excellent stability, with a threshold voltage shift (ΔV th ) of <0.2 V during a 3000 s thermal stability test performed at 200 °C and a bias stress test under a gate voltage of ±20 V. During the implantation process, B ions with high kinetic energy collide with IGZO atoms, resulting in the formation of an oxygen vacancy (V O ) and an oxygen interstitial (O i ) simultaneously. The implanted B ions and O i are bonded such that the V O sites are maintained by the B−O reaction and can contribute to an increase in the carrier concentration in a-IGZO films, thereby increasing the conductivity of the n + region.

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Section: Methodsmentioning

confidence: 99%

Performance Improvement of Self-Aligned Coplanar Amorphous Indium–Gallium–Zinc Oxide Thin-Film Transistors by Boron Implantation

Kang

Lee

Kwak

et al. 2022

ACS Appl. Electron. Mater.

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“…Low temperature poly-silicon (LTPS) thin-film transistors (TFTs) have been widely used for AMOLED displays, due to their superior performance and much better device stability compared with conventional amorphous silicon and emerging oxide semiconductor TFTs. [1,2] However, due to stringent end-product requirements, thin film transistor (TFT) backplanes still have many challenges, such as hysteresis, negative bias temperature instability (NBTI), which plays a critical role on the performance of flexible AMOLED display, such as image sticking. Many groups have reported that short-term image sticking can be greatly improved by reducing hysteresis.…”

Section: Introductionmentioning

confidence: 99%

3‐2: Invited Paper: Instability Issues of LTPS TFT for High Performance of Flexible AMOLED Display

Zhao

Chen

Xing

et al. 2021

Symp Digest of Tech Papers

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We present here a combined theoretical and experimental investigation on hysteresis improvement of LTPS TFTs via optimizing hydrogen content in poly‐silicon and adjusting density of states at poly‐Si/oxide interface. It can be demonstrated that hysteresis seems to be more dependent on the difference in trap density between the bandedge and midgap energy levels. A new method named just noticeable current difference (JND_Current) is employed to evaluate TFT reliability and short‐term image sticking. Incorporating the optimized processes of a‐Si deposition, cleaning conditions before gate‐insulator (GI) deposition and contact hole annealing is helpful to improve instability of LTPS TFTs. The hysteresis level (ΔVth) can be reduced to 0.11V, and also an improvement in quantized level of short‐term image sticking by 35%.

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“…Organic light-emitting diode (OLED) displays have been widely used for various display applications due to wide viewing angle, high contrast ratio, and flexible display applicability [1]. In OLED displays, low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) having high field-effect mobility and high reliability are commonly used in pixel circuits for mobile applications [2]- [4]. However, there is an issue of recoverable residual image, where previous image remains faintly in the following image [5], [6].…”

Section: Introductionmentioning

confidence: 99%

9‐4: Late‐News Paper: Alleviation of Recoverable Residual Image Phenomenon of Flexible Organic Light‐emitting Diode Display

Hong

Hwang

Hwang³

et al. 2019

Symp Digest of Tech Papers

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These authors contributed equally to this work Abstract Electric field shielding (EFS) layer inserted low-temperature polycrystalline silicon thin-film transistor was suggested to alleviate recoverable residual image phenomenon in organic light-emitting diode display using polyimide substrate. It was found that the recoverable residual image was strongly attributed to charge distribution inside polyimide, and it can be inhibited by EFS.

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Anomalous Kink Effect Induced by Bottom-Shield-Metal in LTPS TFTs on Plastic Substrates

Cited by 10 publications

References 21 publications

Performance Improvement of Self-Aligned Coplanar Amorphous Indium–Gallium–Zinc Oxide Thin-Film Transistors by Boron Implantation

Performance Improvement of Self-Aligned Coplanar Amorphous Indium–Gallium–Zinc Oxide Thin-Film Transistors by Boron Implantation

3‐2: Invited Paper: Instability Issues of LTPS TFT for High Performance of Flexible AMOLED Display

9‐4: Late‐News Paper: Alleviation of Recoverable Residual Image Phenomenon of Flexible Organic Light‐emitting Diode Display

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