MEMS sensors are increasingly used in modern combustion engine vehicles due to their precision, reliability, small size, and cost efficiency. However, harsh environments like combustion chambers and exhaust systems present new challenges for these sensors. To ensure performance in such conditions, new thermally, chemically, and mechanically stable thin films are essential. This requires determining the material properties of custom-developed thin layers to enable sensor design, optimization, and reliability over its intended lifespan. High-temperature material characterization and reliability testing methods have been developed for three material systems studied in this work, each with specific testing objectives. The thermal conductivity and capacity of SiO2 deposited via PECVD were measured using structures with a silicon oxide stripe sandwiched between platinum stripes. For LPCVD SiC, electrical and mechanical characterization involved test structures like Van der Pauw and Circular Transition Length methods, as well as electrostatically driven cantilevers. Notably, both thermal and mechanical test structures are driven and read out electrically, facilitating rapid characterization of numerous samples. Additionally, FIB cuts, SEM imaging, XPS, XRD analysis, and resistivity measurements were employed on platinum to investigate grain structure evolution and diffusion at elevated temperatures, along with a qualitative and quant
