Energy Dissipation in Folded-Beam MEMS Resonators Made from Single Crystal and Polycrystalline 3C-SiC Films

This paper examines energy dissipation in MEMS folded-beam resonators made from single crystal and polycrystalline 3C-SiC (poly-SiC) films. The single crystal films were grown at 1280degC by atmospheric pressure chemical vapor deposition (APCVD) while the polycrystalline films were deposited by low pressure chemical vapor deposition (LPCVD) at 900degC. Testing was conducted a pressure of 30 muTorr using a transimpedance amplifier-based circuit. Results show that the quality factor is five times higher for the single crystal SiC devices than the poly-SiC devices. Analysis of the principal components governing energy dissipation indicates that the difference is due to film micro structure and the associated internal losses.