Chan Woo Park

Stretchable Organic Thin-Film Transistors Fabricated on Wavy-Dimensional Elastomer Substrates Using Stiff-Island Structures

Stretchable organic thin-film transistors (OTFTs) were fabricated on the polydimethysiloxane (PDMS) elastomer substrates by employing the wavy-dimensional and polyimide stiff-island structures. A low-temperature solution process was also designed to obtain high strain profiles. The endurable maximum strains were estimated to be 2.28, 9.70, and 9.32% for the OTFTs formed on the flat, 1D-, and 2D-wavy PDMS elastomers, respectively. The field-effect mobilities were obtained to be 5 ~ 7 × 10-4 cm2 V-1 s-1 for all devices and they did not exhibit any degradation under the stretchable conditions before the fracture. The results suggest that the proposed methodologies were quite suitable for high-performance stretchable OTFTs.

A 5.8 GHz mixer using SiGe HBT process

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz down-conversion mixer for DSRC communication system is designed and fabricated using 0.8 ¿m SiGe HBT process technology and RF/LO matching circuits, RF/LO input balun circuits and IF output balun circuit are all integrated on chip. The measured performance is 7.5 dB conversion gain, ¿2.5 dBm input IP3, 46 dB LO to RF isolation, 56 dB LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage and the chip size of fabricated mixer is 1.9 mm × 1.3 mm.

Non-volatile organic ferroelectric memory transistors fabricated using rigid polyimide islands on an elastomer substrate

The authors fabricated stretchable organic ferroelectric memory transistors (OFMTs) on a polydimethylsiloxane substrate using rigid polyimide island structures. The OFMTs exhibited a field-effect mobility of 4 × 10−2 cm2 V−1 s−1 and a current on/off ratio of 105 with a notably low threshold voltage. Furthermore, our memory TFTs exhibit excellent mechanical stability, showing no noticeable change in electrical performance up to a large strain of 50%. These results indicated the feasibility of a promising device for stretchable electronic systems.

Spontaneously Formed Wrinkled Substrates for Stretchable Electronics Using Intrinsically Rigid Materials

The preparation of a stretchable substrate was carried out by blending poly (ethylene glycol)-block-poly (propylene glycol)-block-poly(ethylene glycol) and polydimethylsiloxane (PDMS) to enhance the stretchability and the surface energy of the elastic film. The deposition of a thin parylene film on this modified PDMS led to the formation of a spontaneously wrinkled surface, resulting in a highly stretchable substrate. Rigid Au conductors were deposited on the resultant wrinkles substrates, and could be stretched up to 20% strain. In addition, stretchable pentacene thin-film transistors were successfully fabricated on the wrinkled substrate without the formation of stiff islands.

Freely Deformable Liquid Metal Grids as Stretchable and Transparent Electrodes

A new structure of stretchable and transparent metal-grid electrodes is described, where a liquid metal alloy, eutectic gallium–indium (EGaIn) is employed as a stretchable conducting material. By a “roll-painting and lift-off” technique based on photolithography, stretchable EGaIn-grids with the linewidth of 20 <inline-formula> <tex-math notation=LaTeX>

Locally-tailored structure of an elastomeric substrate for stretchable circuits

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Ti-Si-Ge formation on the extrinsic base of SiGe heterojunction bipolar transistors

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RF performance tradeoffs of SiGe HBT fabricated by reduced pressure chemical vapor deposition

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STRETCHABLE ELECTRIC DEVICE AND MANUFACTURING METHOD THEREOF

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Stretchable electronic device and method of manufacturing same

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