Micro shell resonator with T-shape masses for improving out-of-plane electrostatic transduction efficiency

This paper presents a novel micro shell resonator (MSR) with eight circular-distributed T-shape masses based on fused silica (FS), which is fabricated by combining micro blowing-torch process with high precise mold. FS is been heated instantaneously above the softening point by micro blowing-torch and flow down into the mold. The resonator shell is shaped using a pressure difference and surface tension whose precision is determined by the precision of mold. The key process is that eight T-shape masses are defined along the rim of resonator shell. Electrostatic transduction is used to detect spatial deformation of resonators by out-of-plane electrodes, which has wineglass modes at 10.27 k and 10.70 k with quality factors of 12558 and 6964. A large capacitance enabled by T-shape masses for driving and sensing is measured as 1.31pF~1.6pF, which improves out-of-plane transduction efficiency. Besides, it is more convenient to trim the frequency by adding or removing mass on the T-shape masses.