Propose a new processing method based on cavity-in-SOI（ C-SOI） technology to fabricate capacitive micromachined ultrasonic transducer（ CMUT）. Key technical steps used in fabricating process are tested

it shows that the size of fabricated sensor is basically in accordance with the designed value

and cavities are uniform in height and the wafer bonding has obtained good effects

thus prove feasibility of process flow. Furthermore

it show that resonant frequency and static capacitance has good uniformity by testing on the designed array

which indicates that the CMUT devices based on C-SOI technology meet design requirements and are suitable for processing large arrays

and make it possible to process imaging array.