Ultrathin flexible thin film transistors with CYTOP encapsulation by debonding process

Kim, Jae Moon,Oh, Jongsu,Jung, Kyung-Mo,Park, KeeChan,Jeon, Jae-Hong,Kim, Yong-Sang Institute of Physics 2019 Semiconductor science and technology Vol.34 No.7

<P>We fabricated ultrathin flexible thin film transistors with hydrophobic encapsulation layer by debonding process. In the debonding process, to separate the transistors from the carrier glass in deionized (DI) water, a strong hydrophobic material such as CYTOP was used for encapsulation, thus increasing their resistance to moisture. PVA was used as a release layer and the debonding process was optimized to separate the carrier glass and the transistors. It was confirmed that water penetration into the device can be suppressed effectively when the CYTOP thickness is 800 nm. In addition, the electrical characteristics remained almost constant even in the presence of water for 50 min. The total thickness after debonding process was approximately 2 <I>μ</I>m. Waterproof experiments and debonding process were performed for a simple inverter circuit as well as a discrete device, and the operation and voltage gain of the inverter did not change when water was placed on the device or after debonding process. Finally, the flexibility was measured by transferring the device to a flexible PI substrate. Consequently, it was confirmed that degradation in the electrical properties was slightly up to a bending radius of 2.5 mm.</P>

Modelling localized charge-injection region of the p-channel low-temperature polycrystalline silicon thin-film transistor

Choi, KwangHyun,Sohn, YoungHa,Moon, GeumJu,Kim, YongSang,Jeon, Jae-Hong,Park, KeeChan The Korean Infomation Display Society 2018 Journal of information display Vol.19 No.1

The low-temperature polycrystalline silicon (LTPS) thin-film transistor (TFT) is the optimal device for the backplane of the organic light-emitting diode display. At the end the p-channel LTPS TFT fabrication, a charge-injection stress with a strong negative drain bias and a positive gate bias are applied to reduce the off-current by injecting electrons into the gate insulator near the drain. In this study, the charge density and the length of the charge-injection region in the gate insulator were estimated by comparing the measured TFT characteristics with the simulation models with various charge-injection lengths and charge densities. It was found that the effective length of the charge-injection region was $0.96{\mu}m$ and the charge density was $-3{\times}10^{12}/cm^2$ for the $2-{\mu}m$-channel-length device when $V_{GS}$ was +20 V and $V_{DS}$ was -10 V under the charge-injection stress condition. It was also found, based on the analysis of the electric field distribution under the bias stress condition, that the charge density and the length of the charge-injection region were invariant against the channel length variation. Therefore, the measured TFT characteristics also accorded closely with the simulation models for different channel lengths, such as 4 and $10{\mu}m$, when the same characteristic values of the charge-injection region were employed.

P181 Secondary cutaneous DLBCL has a higher IPI score and worse prognosis than DLBCL, leg type

( Hojeong Shin ),( Woojin Lee ),( Kwanghee Won ),( Chonghyun Won ),( Sungeun Chang ),( Jeeho Choi ),( Keechan Moon ),( Chansik Park ),( Jooryung Huh ),( Cheolwon Suh ),( Miwoo Lee ) 대한피부과학회 2016 대한피부과학회 학술발표대회집 Vol.68 No.2

<div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div><div style="display:none">fiogf49gjkf0d</div> Background: Differences in skin lesions and survival data for cutaneous diffuse large B-cell lymphoma (DLBCL) depending on primary tumor site are currently unknown. Objectives: we aimed to analyze the clinical features of skin lesions and survival outcomes of cutaneous DLBCL according to the primary tumor site. Methods: Forty-seven patients with cutaneous DLBCL were classified as primary cutaneous DLBCL or cutaneous DLBCL secondary to primary disease. Clinical features, survival outcomes, and prognostic factors were analyzed using patient medical records. Survival outcomes were analyzed using the Kaplan.Meier method and compared using the log-rank test. Results: Although skin lesion characteristics did not significantly differ between groups, secondary cutaneous DLBCL more commonly presented disseminated skin lesions that involved multiple anatomical sites. Primary cutaneous DLBCL demonstrated a less aggressive clinical course and better survival outcomes than secondary cutaneous DLBCL. Disseminated skin lesions and a location on the leg significantly affected the prognosis of primary cutaneous DLBCL. The multiplicity of skin lesions and time point of cutaneous involvement were associated with prognosis in secondary cutaneous DLBCL. Conclusion: Although the clinical features of skin lesions were similar regardless of subgroup, survival outcomes and prognostic factors differed depending on the primary tumor site of cutaneous DLBCL.

Bending Performance of Flexible Organic Thin-Film Transistors With/Without Encapsulation Layer

Oh, Jongsu,Kim, Jin-Ho,Lee, So Young,Kim, Min Su,Kim, Jae Moon,Park, Keechan,Kim, Yong-Sang IEEE 2018 IEEE transactions on device and materials reliabil Vol.18 No.1

<P>Flexible pentacene-based organic thin-film transistors (TFTs) were fabricated and their performance was investigated as a function of the bending radius and the thickness of the polydimethylsiloxane (PDMS) encapsulation layer. The TFTs were fabricated on a flexible polyimide film (film thickness: 75 <TEX>$\mu \text{m}$</TEX>), and encapsulated by a PDMS layer. Degradation of the device performance during application of a tensile bending stress of 3 mm was minimized by utilizing an encapsulation layer thickness of 75 <TEX>$\mu \text{m}$</TEX>, because the mechanical strain on the pentacene layer was almost off-set (tensile strain was applied to the bottom layer of the pentacene, and compressive strain was applied to the top layer of pentacene). At the tensile bending stress of 3 mm, the performance of the non-encapsulated TFT was degraded, whereas the encapsulated device showed great stability. This flexibility and bending stability were enabled by the use of the 75- <TEX>$\mu \text{m}$</TEX> PDMS encapsulation layer, due to the location of the pentacene active layer in the neutral region position. A mechanical reliability test was performed for 120 min with a bending radius of 3 mm, demonstrating that only the device with the 75- <TEX>$\mu \text{m}$</TEX> thick encapsulation layer showed stable device performance over a stress time of 120 min.</P>

Solution-Processed Aluminum-Zirconium Oxide as a Gate Dielectric for InGaZnO Thin Film Transistors

Han Jeong Hun,Lee So Young,Kim Hyo Eun,Jeon Jae-Hong,Park KeeChan,Moon Kook Chul,Im Hwarim,Kim Yong-Sang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

This study presents a solution-processed aluminum-zirconium oxide (AlZrOx) dielectric for amorphous indium-gallium-zinc oxide (a-IGZO) thin-flm transistors (TFTs). Solution-processed AlZrOx thin flms exhibit overall improved dielectric properties, such as leakage current characteristics of 1.10× 10–8 A/cm2 at 0.5 MV/cm and high dielectric constants of approximately 9.1 by combining the advantages of aluminum oxide (AlOx) and zirconium oxide (ZrOx). Solution-processed IGZO TFTs using the AlZrOx flm as a gate insulator layer exhibited a threshold voltage of 0.64 V, feld-efect mobility of 3.06 cm2 /V s, and a subthreshold slope of 0.26 V/dec. In addition, the IGZO TFTs with the AlZrOx flms exhibited a higher on/of current ratio of 1.05× 106 than devices with the AlOx and ZrOx gate insulator layers. The improvement of device properties is mainly attributed to the interface properties. The IGZO TFTs with the AlZrOx gate insulator exhibited the lowest interface trap density of 2.07× 1012 cm−2 eV−1, compared to the devices with the AlOx and ZrOx gate insulators of 3.30× 1012 and 5.06× 1012 cm−2 eV−1, respectively, because of the smooth surface roughness and reduced residual hydroxyl groups in the flms. The IGZO TFTs with the AlZrOx gate insulator also improved hysteresis characteristics with the hysteresis window of 0.17 V. This study presents a signifcant step toward developing low-cost, low-power-consumption, and high-performance oxide electronic device.