Abnormal Output Characteristics of p-Type Low Temperature Polycrystalline Silicon Thin Film Transistor Fabricated on Polyimide Substrate

Symp Digest of Tech Papers

Baek

et al. 2017

In this paper, one of goals is to elucidate Vt behaviors of a top gate LTPS-TFT fabricated on the PI substrate exposed to the negative bias temperature stress (NBTS), hot carrier injection (HCI) and breakdown voltage (BV). Physical and device characterization intend to comprehend the structural dependency of LTPS-TFT on Vt stability and reliability in comparison to the glass substrate. It is found that turn-over Vt behaviors of a top gate LTPS-TFT on the polyimide (PI) substrate depends on negative bias temperature stress (NBTS) conditions. Vt behaviors are attributed to LTPS-TFT structure dependent intrinsic negative charges at the interface between the barrier and PI substrate, causing the accumulation of positive charges at the poly-Si back channel. In fact, intrinsic process parameters, such as barrier thickness and PI cure conditions, play important roles to control interfacial charges at the interface. Finally, streamlined barrier process enables LTPS-TFT on PI substrate to expand advanced flexible applications without compromising luminescence and reliability. KeywordsVt turn over phenomenon; LTPS TFT; barrier process optimization; negative bias temperature stress; reliability P-137 / J. Kim SID 2017 DIGEST • 1775

Section: Resultssupporting

confidence: 69%

P‐137: Vt Behaviors of LTPS‐TFT Fabricated on PI substrate for Flexible Applications

Symp Digest of Tech Papers

Baek

et al. 2017

“…due to increased phonon scattering, reveal either a more pronounced saturation regime or even an N-shaped negative differential resistance (N-NDR) upon self-heating. Mostly, field-effect transistors show this kind of behavior in the saturation regime of the output characteristics 11 – 15 . On the other hand, bipolar transistors can show S-shaped negative differential resistance, typically seen in the Gummel plot 16 – 18 .…”

Section: Introductionmentioning

confidence: 94%

Non-Linear Self-Heating in Organic Transistors Reaching High Power Densities

Klinger

Fischer

Kleemann

et al. 2018

Sci Rep

The improvement of the performance of organic thin-film transistors is driven by novel materials and improved device engineering. Key developments are a continuous increase of the charge carrier mobility, a scale-down of transistor dimensions, and the reduction of contact resistance. Furthermore, new transistor designs such as vertical devices are introduced to benefit from drastically reduced channel length while keeping the effort for structuring moderate. Here, we show that a strong electrothermal feedback occurs in organic transistors, ultimately leading to output characteristics with regions of S-shaped negative differential resistance. For that purpose, we use an organic permeable-base transistor (OPBT) with outstanding current densities, where a strong and reproducible, non-linear electrothermal feedback is revealed. We derive an analytical description of the temperature dependent current-voltage behavior and offer a rapid investigation method for material systems, where a temperature-activated conductivity can be observed.

“…It allows the fabrication of a low‐temperature polycrystalline silicon (LTPS) transistor array, which serves as the driving device for AMOLEDs. The bending radius (≥2 mm) and stretchability of the LTPS array on a PI film are limited by the stiffness of PI itself and the use of a brittle gate insulator such as SiO 2 . PDMS is an alternative soft substance for substrates that offers stretchability to the large transistor arrays.…”

Section: Introductionmentioning

confidence: 99%

Network Structure Modification‐Enabled Hybrid Polymer Dielectric Film with Zirconia for the Stretchable Transistor Applications

Hur

et al. 2020

Adv Funct Materials

Stretchable electronic devices should be enabled by the smart design of materials and architectures because their commercialization is limited by the tradeoff between stretchability and electrical performance limits. In this study, thin‐film transistors are fabricated using strategies that combine the unit process of a novel hybrid gate insulator and low‐temperature indium gallium tin oxide (IGTO) channel layer and a stress‐relief substrate structure. Novel hybrid dielectric films are synthesized and their molecular structural configurations are analyzed. These films consist of a polymer [poly(4‐vinylphenol‐co‐methylmethacrylate)], cross‐linkers having different binding structures [1,6‐bis(trimethoxysilyl)hexane (BTMSH), dodecyltrimethoxysilane, and poly(melamine‐co‐formaldehyde)], and an inorganic zirconia component (ZrOx). The hybrid film with BTMSH cross‐linker and 0.2 M ZrOx exhibits excellent insulating properties as well as mechanical stretchability. IGTO transistors fabricated on polyimide‐coated glass substrates are transferred to the rubber substrate to offer stretchability of the transistor pixelated thin‐film transistors. IGTO transistors fabricated on stretchable substrates using these strategies show promising electrical performance and mechanical durability. After 200 stretchability test cycles under uniaxial elongation of approximately 300%, the IGTO transistor still retains a high carrier mobility of 21.7 cm2 V−1 s−1, a low sub‐threshold gate swing of 0.68 V decade−1 and a high ION/OFF ratio of 2.0 × 107.