3C-SiC films on insulated substrates for high-temperature electrostatic-based resonators

Here, we report on a comparison between two different insulated substrates, semi-insulated silicon (SIS) and silicon-on-insulator (SOI), used for the growth of 3C-SiC for electrostatic-based mechanical resonators able to operate at high temperatures. The epitaxial growth of monocrystalline 3C-SiC films in these starting materials is first described and the main encountered problems are discussed. Structural and morphological characterization of the SiC layers is then performed using an optical microscope, a scanning electron microscope, an atomic force microscope and x-ray diffraction. Raman spectroscopy is also used to study the residual stress. Then, innovative lateral electrostatic SiC resonators using these materials are fabricated and electrically tested. Globally, devices using a SOI substrate allowed electrical sensing without any associated circuitry. Temperature measurements of the electrical resonance up to 200 °C are also performed and demonstrate that SiC on SOI is a promising material for a new generation of a harsh-environment-resistant micro-electro-mechanical system.