Displacement Profile of Micromachined Nano-Electro-Mechanical-Ultrasonic Pressure Sensor: A Comparative Analysis

The present study aims to unveil the efficacy of three different theoretical models namely both sides clamped circular plates model, clamped circular model with nonlocal plate theory (modified for nano scale) and membrane displacement model using silicon nitride (Si
3
N
4
) capacitive micromachined ultrasonic transducer (CMUT). To address the edge effects in calculation of capacitance of CMUT which should not be neglected in case of small dimension like micrometer or less, Landau & Lifschitz method of fringing has been incorporated in all these three models to precisely compute the displacement profiles. To validate these analytical models, the Finite Element Modelling (FEM) model has been built with COMSOL. The thorough investigation for various radius and thickness of the diaphragm of the CMUT has been done to reveal the superiority of a particular analytical model depending on the CMUT dimension.