Investigation on the collapse voltage using different structural parameters of micromachined ultrasonic transducer

Abstract The study is to determine how device collapse voltage is affected by different structural parameters of Micromachined Ultrasonic Transducer (MUT). Capacitance MUT (CMUT) have potential applications in non-contact, non-destructive examination of thin metal films, gas flow metering, high intensity ultrasonic therapy and non-invasive medical imaging. In this study, we have investigated using COMSOL Multiphysics for modeling and studying the physical behaviour of CMUT which is then compared with the analytical model along with experimental data. Different collapse voltages are obtained with the device structural parameters as well as with the materials used for the membrane and electrode. From the study, it is observed that using Si 3 N 4 rather than SiC and diamond as the membrane materials achieved the desired performance of the device. The device stress analysis results are also shown for three different membrane materials, where higher stress lowers the device resonance frequency. Furthermore, the analyses done for vented membrane showcases a significant impact on the device resonance frequency. The simulated collapse voltage of 108 V also demonstrates strong agreement with existing experimental and theoretical results. Reported collapse voltages for CMUT devices typically range from 71 to 135 V, depending on geometric parameters and operating modes, with comparable structures exhibiting values close to 134 V.