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Study of possibilities of thin layers depth profiling by combined use of SIMS and ToF-LEIS methods.

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Polymeric waveguide-on-flex has the potential to replace complex and costly light-turning devices in optoelectronic applications. As light signals are propagated and confined through the definition of core-cladding interface, the light guiding structure is required to adhere well and ensure long term interfacial stability. This thesis addresses the gap that has emerged in the fundamental material issues such as the polymeric optical waveguide materials deposited on the flexible substrates. In addition, this thesis investigates the feasibility of a new approach using electrostatic-induced lithography in micro-patterning of polymer, in optical waveguide fabrication. Plasma treatment is applied to enhance interfacial adhesion between flex substrates and optical cladding layers. The modified flex surfaces of polyimide KaptonHNTM and liquid crystal polymer VecstarTM materials are characterised. In addition, sonochemical surface treatment is evaluated on these flexible substrates. ToF-SIMS depth profiling has confirmed the interface reaction mechanisms where it has shown that plasma treatment increases the interfacial interpenetration. The larger interfacial width increases the possible entanglement mechanism between the polymer chains. These results, together with the double cantilever beam testing, indicate the strengthening of the polymeric interface upon plasma treatment, which is essential for long term optical and mechanical stability of waveguide-on-flex applications. A new method of micro-pattering of polymer material has been adopted for fabricating multimode waveguide-on-flex. The method, using an electrostatic-induced lithography, is developed to produce 50 μm x 50 μm arrays of polysiloxane LightlinkTM waveguide on flex. This thesis looks at various process recipes of the technique and reports the pattern formation of polymeric optical core. By adjusting the spin-coated liquid core thickness, pre-bake condition, UV exposure and applied voltage, the aspect ratio and profile of the optical core microstructure can be varied. As the electrostatic pressure overcoming the surface tension of spin-coated waveguide material induces the optical core formation, the core structure is smooth, making it ideal for low scattering loss waveguide. The propagation loss of fabricated waveguide is measured at 1.97 dB/cm at 850 nm wavelength. The result shows that the use of electrostatic-induced lithography in optical polymer is a promising approach for low cost and low temperature (<150 °C) processing at back end optical-electrical integrated circuitry assembly.

Předložená diplomová práce se zabývá implementací metody rentgenové emisne indukované částicemi do experimentálního uspořádání za účelem doplnění rodiny metod založených na iontových technikách, tj. Rutherfordovy zpětné rozptylové spektrometrie, spektrometrie elastického zpětného rozptylu a analýzy detekce doby letu/energie elastického odrazu. Výhoda více-metodického přístupu je demonstrována na vrstvách ze slitin přechodných kovů obsahujících lehké prvky, kde samo-konzistentní analýza poskytuje výrazně zlepšené a přesné informace o stechiometrii, hloubkovém rozložení a tloušťce slitiny. Hmotnostní spektrometrie sekundárních iontů je použita pro porovnání a doplnění získaných výsledků.

This thesis is devoted to the behavior of heavy metals in gettering multilayers made of polysilicon and silicon oxide.

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