Resonant transducer, manufacturing method therefor, and multi-layer structure for resonant transducer

A resonant transducer includes a silicon single crystal substrate, a silicon single crystal resonator disposed over the silicon single crystal substrate, a shell made of silicon, surrounding the resonator with a gap, and forming a chamber together with the silicon single crystal substrate, an exciting module configured to excite the resonator, a vibration detecting module configured to detect vibration of the resonator, a first layer disposed over the chamber, the first layer having a through-hole over the resonator, a second layer disposed over the first layer, the second layer covering a gap being positioned above the through-hole and being communicated with the through-hole, and a third layer covering the first layer and the second layer, and the third layer sealing the gap.