Design And Simulation Of CMUT

Ultrasonic inspection and control technique is based on collecting information through ultrasonic. The technique works without damage and contact to the object. In the field of ultrasonic inspection, the traditional PZT device have the problem in match the acoustic impedance between the air and PZT. Moreover the traditional fabrication process set limitations to the fabrication of both low frequency and high frequency devices. Moreover, releasing these membranes is difficult due to large capillary force during the drying process. Wafer-bonding technique is used in fabricating the cMUT(Capacitive Micromachined Ultrasonic Transducer) in this project. In the wafer-bonding technique, the membrane and the cavity are defined on separate wafers that are bonded under vacuum conditions. Wafer-bonding could fabricate the low frequency ultrasonic transducer .The wafer-bonding technique could simplify the cMUT fabrication process and charged lower cost. And the device fabricated by this technique has a small volume , low noise and is easy to integrated to the system with little influence of the environment. The wafer-bonding technique is a promising way in fabricating cMUT.This research refers to the cMUT's working theory and fabrication process. Consult lots of papers of cMUT. Introduce the development of the cMUT in the field. This research analyses the mechanical electric coupling through ANSYS . The cMUT structure is simulated with mechanical electric coupling and the structure is optimized according to result of the simulation. The project did the statics structure analysis ,mode analysis and harmonic analysis using the TRANS 126 unit by GUI. The method is simple and effective in designing the cMUT structure and circuit system. In the fabrication process ,the Wafer-bonding Technique, Dual Surface Lithography, High Doped Boron Technique and Self-etch Stop Technique were used. Especially, the Wafer-bonding technique was used in the process, it is very significative and creative.