Micro-electro-mechanical-system based capacitive ultrasonic transducer as an efficient immersion sensor

Abstract

In this paper we have analyzed the influence of the membrane inherent residual stress along with its Young’s modulus for evaluating the characteristics of a capacitive micromachined ultrasonic transducer (CMUT) for medical imaging and sensor applications. The membrane displacement profile, the frequency response characteristic and the coupling coefficient are evaluated and a close conformity with the PZFlex Finite Element method (FEM) simulations has been confirmed. The variation of the coupling coefficient with the different structural parameters indicates the use of thinner membranes with lower transduction gap as efficient transducers. Moreover, coupling factor increases as bias increases and an investigation of the collapse voltage is essential. Various coupling mediums are analyzed to find the transducer equivalent resistance and quality factor to predict its utility as a sensor for gaseous and liquid coupling mediums.