In English

Photo-structuring of Organic Layers for Flexible Electronics

Göteborg : Chalmers tekniska högskola, 2013. 88 s. Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology, ISSN 1652-0769, 2013.
[Examensarbete på avancerad nivå]

Even though inorganic Thin Film Transistors are widely used in semiconductor industries at present, organic Thin Film Transistor (OTFT) is a fast developing technology that shows flexibility in production with ultra-low cost. In recent years, wide research are made with an aim to improve the performance of OTFTs. This master thesis project was carried-out to process and characterize a high-k organic polymer dielectric of dielectric constant >3, without any pin-holes or cracks thus realizing high breakdown voltage and to build circuitry structures on it. The lithography step for patterning the dielectric was done by photo-illumination at I-line (365nm). Achieved sharp and clear patterns, but the polymer dielectric suffered relatively high layer loss during developing due to poor cross-linking and adhesion. IR and UV/vis analysis were made and it was found that the polymer dielectric was absorbing at shorter wavelength; thus device structures were fabricated at a UV wavelength of 254 nm. This project also involved laser patterning of active p-type polymer organic semiconductor (OSC) around the TFTs contact pads to avoid cross-talk between the transistors via the active material. Nd:YAG, high-intensity multiple short pulsed UV laser of wavelength 355 nm with ~15 ns pulse duration at 10 kHz was used to pattern the devices. SAM (Self-assembled monolayer) treatments were also done on the SiO2 dielectric surface to modify the morphology of dielectric-OSC interface and laser writing of the active material was performed and compared for different SAMs. Minimized off-state current and reduced gate leakage was realized with laser patterning.

Nyckelord: thin film transistor, polymer dielectric, organic semiconductor, photolithography, laser patterning, spin coating, laser ablation, self-assembled monolayer, surface treatments

Publikationen registrerades 2014-01-18.

CPL ID: 192852

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