Manufacturing method of multi-frequency CMUT device and multi-frequency CMUT device

The invention provides a manufacturing method of a multi-frequency CMUT device and the multi-frequency CMUT device. The method comprises the steps: selecting a high-concentration doped silicon wafer as a substrate to manufacture a silicon-based layer; arranging an insulating layer on the upper surface of the silicon-based layer; depositing amorphous silicon on the upper surface of the insulating layer to prepare a sacrificial layer and define a CMUT unit, wherein the sacrificial layer comprises a circular main body and a plurality of release channels connected with the circular main body; depositing a vibration film on the CMUT unit; forming a corrosion hole in the opening position of each release channel, and releasing the sacrificial layer to form a cavity; sealing the corrosion hole after the sacrificial layer is released; etching a supporting wall with a preset width around a cavity formed by the circular main body by using a photoetching process; performing a deep etching operation to the silicon-based l