Analysis of Membrane Yield in Insulated Air-Patched Capacitive Transducers for High-Frequency Applications

This study uses Finite Element Method (FEM) to simulate a microelectromechanical system (MEMS) based Capacitive Micromachined Ultrasonic Transducer (CMUT) cell, emphasizing the effect of air patches on the device's functionality. The analysis reveals total capacitance of approximately 0.46 pF, resonant frequency of 2.7 MHz and maximum membrane displacement of 16.5 nm. The presence of air patch reduces the capacitance due to air's low permittivity, which influences displacement while leaving the natural frequency unaffected. The model also demonstrates a higher collapse voltage of 108.9 V, indicating enhanced robustness. The optimal performance is achieved within a bias range of 40–60 V, capable of withstanding pressures up to 3 atm. These findings provide crucial insights for designing CMUTs with air patches for ultrasonic applications.