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To improve the performance of the central element of the Karlsruhe Micronose—a gas‐sensor microarray—the gas sensitive layer is modified toward a highly porous nanogranular layer. To synthesize those layers, the Karlsruhe Microwave Plasma Process which is in its native form a precursor‐based process to produce nanoparticles with diameters below 10 nm, was modified for in situ tin‐dioxide layer deposition. The produced layers have due to their structure a very large active surface area. The process parameters were optimized to generate thin layers with high surface homogeneity. This was mostly established by significantly reducing the precursor feed and therefore reducing the primary particle size to below 2 nm. The layers were analyzed for their mechanical stability, structural, and chemical properties. It is shown that the precursor residue can be completely removed by applying a default annealing step. The structure of the layers reminds of little clubs starting on top of the substrate growing wider toward the surface. Prototype sensors were fabricated and tested for their gas sensory properties in comparison to a standard gas‐sensor microarray with a sputtered tin‐dioxide layer. The gas‐sensor microarrays with nanogranular layer show an increased signal response of up to one order of magnitude to isopropanol. The time of response is equal in both sensor systems while the time of recovery is nearly doubled for the sensors with nanogranular layer due to increased surface area and gas absorption.

A series of commercially available nanosized barium titanates has been investigated with respect to their use as high-k-ceramic filler in polymer based composites with improved dielectric properties. The thermal treatment of the barium titanate powders at 1,000°C causes a significant increase of the composite's permittivity. X-ray diffraction experiments prior and after heat treatment revealed that the barium titanate with smallest particle size and the largest specific surface area possesses the thermodynamically unstable cubic phase. In case of the other investigated barium titanates the crystal lattice is distorted. Thermal treatment induces the phase change into the tetragonal one and crystal lattice relaxation enabling higher permittivity values. Composites with a solid load around 78 wt% with a bimodal particle size distribution show high permittivities around 50 and a low loss factor around 5% suitable for the realization of embedded capacitors via screen printing or tape casting.

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With respect to applications in microelectronics the frequency and temperature dependent dielectric properties of a series of polymer-based composites, consisting of a thermally curable unsaturated polyester-styrene resin and nanosized strontium titanate filler, have been characterized. Following earlier investigations targeting an improvement of dielectric properties the impact of a thermal treatment of the dielectric filler on the resulting composite properties was determined. In case of composites containing 55 wt% strontium titanate heat treatment at 1,000°C increases the permittivity by almost 25% and lowers the loss factor value by a factor of almost 10 due to grain growth and larger crystallite sizes.

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Polymer matrix composites (PMC) with barium titanate as high-k-active filler have high potential in embedded capacitors within a printing circuit board (PCB) enabling high permittivity values and low loss factors. These PMCs allows for the use of established polymer processing techniques like screen printing and curing, which are compatible to the established PCB-materials and shaping processes. In this work a process chain, starting with a material optimization of the nano-sized barium titanate, dispersed in an unsaturated polyester-styrene reactive resin, and a further specific process development, will be presented. With respect to the optimization of the individual process steps the flow behaviour of the uncured composite, the polymerization process and the dielectric properties were characterized comprehensively. Using a composite with a barium titanate filler load of 74 wt% allows for a dielectric layer formation by a modified screen printing technique. After capacitor mounting and composite curing an initial capacity density of 13.3 pF/mm 2 could be achieved.