Low Temperature CVD SiC Coated Si Microcomponents for Reduced Scale Engines

The unique operating conditions of micro-thermochemical systems introduce many materials compatibility issues that must be addressed, particularly where thin film coatings are concerned. These issues include oxidation, wear, friction, and thermal stability. This work aims to explore the effectiveness of polycrystalline 3C-SiC films deposited by low temperature chemical vapor deposition on silicon substrates as a means for the remediation of these effects. The chemical structure of the deposited films is examined by X-ray photoelectron spectroscopy and X-ray diffraction techniques. Surface physical characteristics are evaluated by atomic force microcopy as well as by scanning electron microscopy. The structural makeup of these films is characterized both optically and by the sample’s resistance to chemical etching. These barrier films are found to conformally deposit and can therefore be used to coat substrates or individual components, as well as to create highly environmentally resistant sensor elements. Samples are exposed to both a non-reactive flow high temperature source and reactive flow condition (H₂–air flame) to determine their survivability. The SiC films are shown to possess a relatively high oxidation resistance when compared to Si.