Silicon-Based Suspended Microchannel Resonator Developed Using Au Thermal Diffusion Bonding for Mass Sensing of Biomaterials

Suspended microchannels are of great interest in applications such as physical and chemical sensor systems. In this study, we developed a suspended microchannel resonator (SMR) by bonding two separate Au-coated silicon–insulator–silicon substrates via thermal diffusion bonding. To obtain a secure bond between Au films, we investigated different bonding temperatures and Au film thicknesses. As a result, we successfully fabricated an SMR. We show that the developed resonator has a resonance frequency of 229.55 kHz and a quality factor of 171 for the empty channel. The response of the channel to absolute mass was 18.7 pg/Hz. The measurement results were in good agreement with the results of numerical simulations. In addition, we estimated the practical mass detectability of the developed SMR via statistical analysis. The developed SMR enabled mass detection with a resolution of 710.6 pg. Our SMR can be produced via typical semiconductor fabrication technology, which is advantageous in terms of mass production. [2023-0164]