Silicon carbide membranes for microelectromechanical systems based cmut with influence factors

Abstract

Microelectromechanical Systems (MEMS) based capacitive micromachined ultrasonic transducer (CMUT) has many applications in medical imaging. Ultrasonic transducer technology has been long dominated by piezoelectric transducers, particularly in the medical ultrasound imaging. The best popular materials used for fabricating CMUT membranes are silicon nitride (Si 3 N 4 ), polysilicon, chromium and aluminum are characteristically used to shape electrodes on top of these membranes. But current technology of CMUT demands the silicon carbide (SiC) for membrane material where the electrode instead of being on top of the membrane is placed beneath the membrane. It offers greatest contiguity of the upper and subordinate electrodes. For this it decreases the transduction gap enlightening the electro-mechanical coupling and sensitivity of the device. Aside from this, it is reported that the CMUT has a resonance frequency of 1.7 MHz and a 3 dB-bandwidth of 0.15 MHz. Also, the higher Young’s modulus (260 GPa) of SiC with its little residual stress (± 30 MPa). Consequences in great strength and resilient CMUT membranes, which led to the studies presented in this paper. All the results are validated by FEM simulation.