Microstructure and mechanical properties of ceramic/self-assembled monolayer bilayer coatings

Thin ceramic coatings/films find their applications in various electronic devices, sensors, and microelectromechanical systems (MEMS) as a protection/barrier layer as well as functional films. Ceramics are, however, susceptible to catastrophic failure due to their inherent brittleness. We have developed a strain-tolerant, bilayer coating consisting of a ceramic layer and a self-assembled monolayer (SAM). The top ceramic coating offers an inert, protective layer, while the underlying SAM acts as a “template” for the subsequent growth of a hard ceramic coating. In this study, we explore the ZrO2/SAM coatings on Si substrates prepared in situ at 80°C in solution. The coatings exhibited good coverage on the silicon surface, but the hardness was rather low. Characterization tools including x-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and nanoindentation were employed to achieve a better understanding of the synthesis and processing of the coatings and their relation to the mechanical properties.