Characterization of Parylene-C using quartz thickness shear mode (TSM) resonators

Due to its high sensitivity, repeatability and easy connection with electrical measurement systems, Quartz thickness-shear-mode (TSM) resonator is adopted to extract the complex shear modulus of Parylene-C films, which play an important role as both an effective wave-guiding layer and biocompatible interfacial layer in Shear-Horizontal Surface Acoustic Wave Device (SH-SAW, Love Mode). Parylene-C films of different thicknesses were deposited on the surface of AT-cut quartz TSM resonators, and admittance spectrums of these uncoated and coated TSM were measured by an impedance analyzer. Results indicated that the ideal thickness range for extraction was from 2.04 μm to 3.55 μm, effectively avoiding inadequate acoustic deformation as well as excessive electrical-response attenuation. The storage modulus G' and loss modulus G" of Parylene-C were 0.155±0.011 GPa and 4.78±0.44 GPa, respectively.