Acoustical properties characterization of a composite made of SU-8 and nanoparticules for BioMEMS application
Résumé
The photoresist SU‐8 (often used in microtechnology) has been acoustically characterized at the frequency of 1 GHz thanks to ZnO transducers. This material will be used to achieve acoustical matching between silicon and water at this frequency and a gain of about 5 dB has been obtained using the combination of this material with a silicon oxyde layer. The acoustical characterization of a composite material made of this photoresist SU‐8 doped with nanoparticules (TiO2 for example) is also presented. The aim is to achieve matching layers with specific mechanical impedance around 5 MRay and depending on the nanoparticules concentration. The targeted application concerns the integration of high frequency ultrasonic transducer in Lab‐on‐Chip for biological cell characterization, especially adhesion properties or biological cells mechanical behaviour. The mechanical impedance and the attenuation of this composite material are characterized around 1 GHz thanks to a standing wave ratio method measuring S11 parameter and extracting the targeted parameters thanks to signal processing.